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[Articles Home]  [Add Article]  

A Vertical Antenna Advantage

Vito Chiarappa (W6TH) on May 18, 2005
View comments about this article!

A vertical antenna advantage:

A 1/4 wave vertical ground mounted has lobes from 10 to 55 degrees and has gain of approximately 3 to 10 dBd. The lift off angle, which is not often mentioned, is 0.35 wavelength from the base of the antenna, where the current is maximum. This portion should be free and clear of any objects to absorb, reflect or distort the waveform.

At a take off angle of 10 degrees the isotropic gain is calculated to be 11.459 dBi. This gain is 11.459 over a isotropic source. In dB, the gain is 10.59 dBd.

At the 55 degrees the gain over an isotropic will be 2.118 dBi or 3.18dBd.

At the 45 degree angle the gain over an isotropic will be 2.546 or 4.116 dBd.

Reasons not often explained are because the ionosphere and the 'D', 'E' layers of high absorption for the low wave angle that a vertical produces.

The dBd is in decibels; the dBi is isotropic gain over a isotrope/isotropic source.

In the evening when the F layer splits into the F1 and F2 layers, this is where the fun begins. The amount of 15 radials is plentiful for any ground mounted vertical antenna, no matter what anyone else will tell you. Although, you may ad as many as you want, it will do no harm.

The cost is very small for the benefit you will derive.

73, W6TH

Member Comments:
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A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
Vito,

I'm all for verticals and I have three of them. Two are home built. Great DX antennas for sure...

But... where did you get these gain figures? "A 1/4 wave vertical ground mounted has lobes from 10 to 55 degrees and has gain of approximately 3 to 10 dBd"

A ground mounted vertical over even good conductivity earth isnt going to have any gain over a dipole at 1/2 wavelength above ground, and in the best case it's gain will be equal to a dipole in free space. Most likely, the gain is going to be less than 2 dBi (around 0 dBd) for a typical vertical installation. With no or few ground radials gain can be significantly less.

The beauty of the vertical isnt in the gain, or lack of, but in the radiation pattern. Great for DX, especially if you don't have a tower and beam or a high dipole.

So, I'm curious where you arrive at those gain figures? You're not doing something sneaky like comparing it to a low dipole, are you?

Regards,

K5DVW

 
A Vertical Antenna Advantage  
by K5UJ on May 18, 2005 Mail this to a friend!
<<<The amount of 15 radials is plentiful for any ground mounted vertical antenna, no matter what anyone else will tell you. >>>

I can assure you that, from my direct personal experience, broadcast stations do not spend money on hardware unless they have a good reason for spending it. If 15 radials were truely enough, every broadcast station operating a base loaded tower would have 15 radials.

I expect a chorus of "HF and ham radio are different" and "studies have shown x radials of y length to be optimum on band z" etc. No, the bottom line is the more radials, the more return current, lower ground resistance relative to driven element resistance and more watts in the air period. There's no free lunch, no magic, or miracles.

Much has been made of the chore of putting down radials. It doesn't have to be hard. You simply have to work efficiently, using the right tools for the job, have a plan in mind ahead of time as to how you are going to lay them out (if you don't have room for all of them straight out from the base), and curb your desire to have 100 of them down in one day. Not gonna happen. 10 a day is more like it. Takes about 1 or 2 hours a day. 3 weeks or so and you're done. (The preceding applies only to radials on the ground.)

The reason hams have trouble with verticals is that they either A. skimp on or blow off the radials or B. buy into the snake oil verticals, for example, the teeny ones that supposedly cover all HF bands (with full-size performance!) or both.
 
A Vertical Antenna Advantage  
by W9PMZ on May 18, 2005 Mail this to a friend!
dBd and dBi are both in dB.

The gain of a dipole of an isotropic radiator is 2.15dB, hence the gain of a dipole is 2.15dBi. A dipole referenced to a dipole is 0dBd.

I'm not sure how you arrive at you figures for a vertical (or I don't have the figures of the top of my head of a vertical). Can you elaborate?

73, Carl - W9PMZ
 
A Vertical Antenna Advantage  
by K8FLY on May 18, 2005 Mail this to a friend!
Verticals are great antenna , much under rated by most of the ham population. signals may not be so big , but you heard it from most every direction . i have a pair of phased 80 mtr verticals here & the do the job nicely & work fine on other bands as well . im so glad i tried a vertical ............ no regrets here.
73s Bill
 
A Vertical Antenna Advantage  
by W3DCG on May 18, 2005 Mail this to a friend!
Oh techno smechno....
Whatever the derivations for gain figures, in the *real world*, with proper respect paid to the ground plane whether ground mounted or not, what is true is:

"In the evening when the F layer splits into the F1 and F2 layers, this is where the fun begins. The amount of 15 radials is plentiful for any ground mounted vertical antenna," and, "The cost is very small for the benefit you will derive."

15 radials is not such a daunting figure. So lead people on with 15 radials. After that they can add 1 every two or three days to the point of diminishing ROI. But at least 15 sounds good, it will do the job, and a person will have the thing up in the air.

If you go saying be sure to lay down those 32 radials, some might stop before they even start. I believe 15 radials would work well enough to take advantage of the reasons why verticals are super. That DUH thing is rather creative though, hee haw.
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
Just one more comment in support of the 15 radial suggestion. I don't see anything wrong with it, practically. Based on my own modeling (oooh, the M word) and that by www.cebik.com, as well as the info in "Low-band DXing", 15 radials is a decent ground system over average earth. Sure, you can gain a dB or maybe 2 if you add 100 more, especially in bad earth areas, but geezh, it's a good start for a minimalist approach!

Heck, elevate the whole antenna system >0.1 wavelength and just use two radials! Even better.

I was under the impression that broadcast stations were REQUIRED by the FCC to have 120 ground radials. I didn't think it was optional and they couldnt use less if they wanted to?
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
Let me explain the gain measurements again. It can be seen that there is an inverse relationship between gain and areas illuminated, for a certain fixed power, there is a simple method of computing the gain of a directional and a vertical antenna. The number of "square degrees" area in the surface of a sphere has been computed to be 41253.

We might be inquisitive, not to prove anything but to simply find the answer and compute the gain of a vertical antenna. We must decide on a reference, which by rights could be isotropic.

A antenna such as the 5/8 wl has a vertical beamwidth to be expected is about 15 degrees. Since the horizontal spread is a full 360 degrees, the approximate number of square degrees is 5400.

15*360=5400 41253/5400=7.63 or 8.84db above isotropic.
Take the log 7.63=0.88*10=8.8dB over a isotropic.

Now for the 1/4 wl:

35*360=12600 41253/12600=3.27 or 5.15dB over a isotropic.
Take the log 3.27=0.514*10=5.14dB over a isotropic.

Comparing the 5/8 and the 1/4 shows there is a difference in gain between the two. The 5/8 wl has 8.8dB and the 1/4 wl has 5.14dB. This indicates the 5/8 wl has a gain of 3.66dB over the 1/4 wl. All in isotropic.

.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
I was under the impression that broadcast stations were REQUIRED by the FCC to have 120 ground radials. I didn't think it was optional and they couldnt use less if they wanted to?


This is ham radio

.:
 
A Vertical Antenna Advantage  
by W4SK on May 18, 2005 Mail this to a friend!

'Round these parts, "an isotropic" is a kind of fruit popsicle sold from the back of an icecream truck.
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
Vito,

On your gain formula example, I think you're mixing apples and oranges. You're quoting beamwidths over perfect conductor ground, but calculating illuminated volume based on an isotropic sphere. You can't do that! The gain will look much larger than it really is. You're also ignoring ground effects, which are very real.

If you don't have a copy of "Low-band DXing" try and get one. There is extensive treatment in the book on real verticals, gain, ground, and all the other issues. Nowhere you'll see gain figures as high as you're quoting. If you trust NEC simulations, give that try too.

Ordinarily, I dont get worked up about quotes of 1 or 2 dB in performance, but 5 and 10 dB, now that's an issue!
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
Read my post again, I was trying to support your 15 radial idea.

AM stations are required to use 120 radials, we obviously arent.

Nevermind.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
K5DVW

I know you were on my side, but thought I would set it up as others to misunderstand and make further comments.

Thanks for your help, which I surely will need and appreciate.

Many read the bad points and never comment on the good points. Amazing how little we know. Hi Hi.

73 my friend and again many tnx.

W6TH.
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
Oh techno smechno....
I like the above comment; I think I am going to gleep it!

Personally I am of the belief, a somewhat well supported belief, that ¼ wavelength Ground Plane antennas have negative gain. Having said that, I am also the guy that took a small 70 centimeter ¼ wave Ground Plane atop a 5000 foot mountain, -- turned its mounting upside-down, and improved the coverage of a 440 MHz system to beautifully cover the INTENDED area.

Prior to that we used a GAIN antenna, of beautiful and costly design! It put a signal out on the horizon so that we could talk to Ventura County. We could not however talk to Orange County down there below the mountain, WHERE WE WANTED TO TALK!

The moral of the story kiddies is, what radiation angle are you seeking? If you want a high angle of radiation such that the signal goes straight up to hit the ‘combined’ F1&F2 layers, and then pretty much straight down again, get a dipole! If you want a somewhat lower angle of radiation to hit the ‘combined’ F1&F2 layers a bit further away (you know, less skips, less signal loss, maybe even designing the radiation patter to hit Europe or wherever on the 2nd or 3rd hop) get a Ground Plane!

Oh, and for a bit of thought on the F1 & F2 layers (as well as the G layer {is that like the G spot}), see below!

http://www.kn4lf.com/F3layer.pdf

73, and good DX’ing de John
PS
Vito, Ya wanna borrow my asbestos shorts? I won’t need them until my next article gets posted!
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 18, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by W6TH on May 18, 2005 Mail this to a friend!

On a vertical antenna the maximum current is at the base of the antenna. Ground losses of vertical radiation are absorbed and then reflected above the earth ground, the unattenuated field is then reflected towards the ionsphere, at 0.35 wl. This is a complex quantity and I would have to show proof by mathematics (trigonometry).<

"On a vertical antenna the maximum current is at the base of the antenna." Well, that's true if the antenna is 1/4WL or 3/4WL tall, but not for other electrical lengths.

I got confused by all the text mingling discussions of 1/4WL and 5/8WL verticals. A 5/8WL vertical doesn't have a current maxima at its base.

WB2WIK/6
 
A Vertical Antenna Advantage  
by K5PSO on May 18, 2005 Mail this to a friend!
So what about an elevated ground plane, with say, a minimum of 9 quarter-wave radials? How would this compare to ground mounted, better? 73 Dan K5PSO
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
K5DVW

This gain calculations is used extensivly and to compare one antenna towards another for both vertical and horizontal beams as well. It is not used for saying that a certain beam or antenna has so much positive forward gain, just for comparison as I have explained.

Let us take the 3 element yagi which is said to be a 7 dBd gain.

60 degree horizontal plane and a 30 degree vertical plane.

60*30=1800 41253/1800=22.9 Log of 22.9=1.36*10=13.60.

3 el yagi 13.60 5/8 vertical 8.84.

13.60-8.84=4.75. Indication of the 3 el yagi has a 4.75dB gain over the vertical.

Not considering the angle of radiation, although the vertical will be much lower, this will come later.

.:This should correct the confusion.
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
So what about an elevated ground plane, with say, a minimum of 9 quarter-wave radials? How would this compare to ground mounted, better? 73 Dan K5PSO


You will have a better match to the 50 ohm impedance with radials down at 45 degrees and a lower angle of radiation.

I believe it would be better for my use.

73 W6TH
.:
 
A Vertical Antenna Advantage  
by N4KZ on May 18, 2005 Mail this to a friend!
A ground-mounted Butternut vertical 120 feet behind my home and in the clear and having 50 60-foot-long radials worked gangbusters for me on 80-10 meters for years until two ice storms ravaged the antenna.

As for radials, I used small gauge, insulated surplus wire I bought for $10 at the Dayton flea market and installed them on top of the ground. Within months, they had sunken into the grass and were no longer visible. I installed all of them in two hours and anchored them in the ground with large nails. Radial installation need not be a big, labor-intensive task.

I worked more than 180 countries on 80m CW with this antenna, including my first-ever JA QSOs on 80, a particularly difficult path from here.

Those lacking sufficient ground space might install their vertical in the air as a ground plane. Equally impressive results can be had with far fewer radials when the antenna is mounted up in the air.

In three decades on the ham bands, I've heard some incorrectly wise-crack about verticals working equally poorly in all directions. Those poor guys obviously never took the time to correctly install a vertical or else they wouldn't make that silly and inaccurate statement.

Verticals represent a tremendous DX value for the money and effort expended.

I love the crank-up tower and nice yagis I have now but sometimes wonder -- in hindsight -- if all the money and time spent on the tower and yagis was worth it compared to my old affordable but highly effective multi-band vertical.

73, Dave, N4KZ
Frankfort, KY
See you in the pile-ups!
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
WB2WIK

I got confused by all the text mingling discussions of 1/4WL and 5/8WL verticals. A 5/8WL vertical doesn't have a current maxima at its base.
-----------------------------------------------------


Fundamentally a Vertical antenna is nothing but a horizontal antenna turned up on end.

The radiation from a ground based vertical is 3 dB above that from a free space dipole.

A 0.626 (5/8) wl height vertical does have more concentrated energy in the forward gain direction. The 5/8 or the 0.625 radiation makes use of the .25 and the .5 elevation angles and is placed within the 5/8 or 0.626 radiator.

73 W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by K2TL on May 18, 2005 Mail this to a friend!
After 41 + years as a Ham, I know that verticals do indeed work well, regardless of all the technobabble either pro or con. However, there are some realities to consider that make verticals less atractive. First, noise. With a vertical ( and I have had many colors and flavors ) I will experience noise that I would never hear at all on a balanced antenna such as the common twinlead fed doublet or coax and balun fed dipole. The difference in noise floor is quite dramatic. The kind of noise I am talking aboput is not just line noise or other electrical junk. I hear computer type squakes all over the place that virtually disappear with the balanced antennas. I have used line isolators at both ends of the coax feed on my verticals and it did nothing for the noise pickup.
Next, close in propagation. I believe most of us will just turn on the rig and work whatever is on at the time. If that is 40 meters at 2pm, then the propagation is going to be close in, around a few hundred miles. A horizontal antenna is going to be better for this distance due to the high angle radiation. Now, if you want to work Pago Pago on 20 meters at dawn, then the vertical will get you there. But I am asleep then and don't care anyway, so my CFD Zepp still makes me happier.
I think that verticals offer a solution for the Ham with limited real estate or a lack of supports for a horizontal antenna. And they do work well. But you just can't beat a balanced horizontal antenna for daily run of the mill operating.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
WA6BFH
John, If I run into a problem, please by all means bail me out. I don't think there is anything that can protect me.

"An open mind is the mark of an intelligent man"

Many thanks for your offer.

73 Vito W6TH.
.:.
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
All the math aside, sorry to burst your bubble but there is no way that the average ground mounted vertical antenna installation is going to give you 3 to 10 dBd... ever!

Don't take my word for it. Model it yourself with NEC, or visit http://www.cebik.com/gp/58.html for an exhaustive essay on this very topic. Be sure to check out the link for topic 1, table 3 and 4. Your exact claim is modeled there in great detail.

See ya,

K5DVW
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
>So what about an elevated ground plane, with say, a minimum of 9 quarter-wave radials?


Actually, if you elevate the feed point, you may only need 2 radials to get the same performance as 100 ground mounted radials. Sloping the radials symmetrically has nothing to do with take off angle and only serves to change feed point impedance.
 
A Vertical Antenna Advantage  
by AA4LR on May 18, 2005 Mail this to a friend!

This is why vertical antennas get such a bad rap -- there's so much mis-information about them.

Since everyone else has picked apart the bad math, I'll leave that alone. The key thing is to understand that a properly installed 1/4 wave vertical and 1/2 wave dipole will both put out about the same maximum gain -- but they put it in different places.

A properly installed vertical will have gain at low radiation angles, and virtually nothing straight up. Depending on the height above ground, a dipole will have gain at higher angles, and perhaps significant gain straight up.

As to radials -- yes, AM radio stations are required to place 120 1/2 wave ground-mounted radials. There's no doubt that such a radial field works very well.

Most hams don't have the real estate to put down this many radials. We usually opt for 1/4 wave radials. 60 1/4 wave ground-mounted radials are virtually indistinguishable from a solid sheet.

Ground conductivity plays an import role in the interplay of these radials. If the ground conductivity is poor -- you don't need as many radials. Counter-intuitive, but true.

As for only using two radials -- there's a lot of myths here, too. If you can elevate your vertical so it is 1/4 wave above ground -- then, yes, three or four 1/4 wave radials is indistinguisable from a solid sheet.

Somewhere the myth started that if you have a few radials elevated just above ground, they are as good as 100 radials on the ground. Modelling seems to confirm this -- but actual field strength measurements show that the 100 radials are better. This appears to be a deficiency in the models with conductors near the ground. That said, a few elevated radials are certainly better than the same number of ground-mounted radials.

Bottom line: if you ground-mount a 1/4 wave vertical, try to put down as many 1/4 wave or longer radials as you can. Strive for 30-50 radials. If you go to 1/2 wave long, try to get more.

I have a shunt-fed tower with 25 0.22 wavelength radials on 80m. It works quite well.

 
RE: A Vertical Antenna Advantage  
by W8JI on May 18, 2005 Mail this to a friend!
I measured verticals near ground with elevated radials and groundplanes, and if you think two radials elevated (or not) is going to be just as good as a larger system you better think again.

Two radials produces a very distorted pattern (3-4dB ripple), and even four radials will distort the pattern (but to a lesser extent). Neither is a perfect ground. Commercial GP antennas I designed and measured required feedline chokes when they had FOUR radials to prevent the feedline from being a significant contributor to radiation. The IEEE has published actual MEASUREMENTS, not models, showing eight 1/4 wl radials 1/4 wl in the air were just ever so slightly less FS than a regular 100 radial system on the ground produced at the same location. So at 1/4 wl height for the 1/4 wl long radials, we know that data of a real system shows the breakeven point is about eight radials.

BC stations use 120 radials because AFTER extensive real world measurements it was determined 50-60 radials put things on the flat part of the curve. The RCA study "Ground Systems as a Factor in Antenna Efficiency" was the defining test. Prior to that test small elevated counterpoises were the standard. The FCC, wanting to be safe, doubled the number and allowed stations using 120 radials to be exempt from some efficiency proofs or measurements.

You don't HAVE to use 120 radials, but if you don't you have to prove the system you have works through a series of measurements.

A 1/4 wl vertical does NOT have 5dBd (or whatever), except perhaps at very low angles where the dipole has a null. Verticals still compare favorably to a high dipole on lower bands, like 160 and 80 meters, for DX.
As an example even with a 318 foot tower that holds dipoles for 160, a 200 foot vertical with 100 200-foot radials ties or beats the dipole in the high 90 percent time area for any contact over a few hundred miles on 160. On 80 meters a 65 foot vertical with 50 radials would tie a 100 ft high dipole night after night into Europe, and of course be much better than the dipole off the ends of the dipole.

In my experience properly constructed verticals will generally beat a low dipole for DX on any band, but NOT a high dipole on the higher bands.

Unless over a perfect infinite groundplane, a 5/8th wave doesn't provide the 3dB gain estimated gain. Over real earth a 5/8th wave can and usually does have a slight loss compared to 1/4 or 1/2 wave vertical antennas.

When you elevate a 5/8th wave, the theoretical 3dB over a 1/4 wave gain goes away pretty fast. That's because a 5/8th wave depends on a very large flat highly conductive groundplane for gain. Same when the 5/8th wave is installed over a small counterpoise.

www.w8ji.com has some data on this.

Everyone is welcome to think what they want, but having measured actual antennas it sure makes me wonder where some of the stuff we read on Internet comes from!!! Some of it is really off the wall, and useless for anyone trying to learn anything useful!

73 Tom
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
K5DVW

Actually, if you elevate the feed point, you may only need 2 radials to get the same performance as 100 ground mounted radials. Sloping the radials symmetrically has nothing to do with take off angle and only serves to change feed point impedance.
-------------------------------------------------------
I do not agree with the EZNEC and the above.

By lowering the radials it becomes closer to becoming a halfwave vertical giving lobes of from 5 to 35 degrees which will give a lower angle of radiation.
Also approaches the impedance of a half wave.

I have found from my antenna range which is over 40 miles in all directions and no trees, homes or obstructions near or close in. (Mojave desert)

With two radials one east and one west this was the maximum radiated power, north and south were nulls, not great, but showed less emitted rf, more so as to a very broad figure 8. The nulls were less due to ground reflections. In free space just like a figure 8. To explain simulate.

EZNEC is not my way of computing and no use of rectangular patterns, but free space patterns. I still enjoy the teaching of Dr. John Kraus, RIP, my college mathematics and so many of our wonderful books of knowledge.

73, W6TH
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
K5DVW

Let me bring out a very important thought;

When some information is applied to a computer or to a device such as the EZNEC and it is in error, just how long will it take to find this error or miscalculation? It could go on forever, could it not? By the method of mathematics and such, the errors can be corrected in seconds, minutes, hours and even day and months, it can be corrected. There will be many who can find errors in written form on any matter.

This way I prefer a way whereby I can check and double check and triple check my work and calculations.

How about giving me some EZNEC on the Rhombic antenna terminated, some day in the near future as It was my favorite antenna while in the military. Imagine at 90 feet above the ground and running 40 KW output with the press wireless transmitters. Changing traffic with Washington, DC from New Delhi, India.

.:
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
>When some information is applied to a computer or to a device such as the EZNEC and it is in error, just how long will it take to find this error or miscalculation?

About as long as it takes me to build the antenna and take it to the calibrated range, which I've done.

My point in all this is that 2 elevated radials can be sufficient for an amateur installation and in most all cases better than a vertical with few to no radials mounted on the ground. That's a fact.

Either way, you're not going to get 10+ dBi out of a vertical, ever!

I'm in no way knocking verticals since I use them, but I am questioning your analysis. Perhaps EZNEC would have predicted the correct gains? :)
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
W4SK,
'Round these parts, "an isotropic" is a kind of fruit popsicle sold from the back of an icecream truck.

These are long gone John. I miss them at this time of the year.

73, W6TH
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
K5DVW

Either way, you're not going to get 10+ dBi out of a vertical, ever!
-------------------------------------------------

No-one has said that. I feel you do not understant this post. Try reading all over again. Start from the beginning, please. (slowly).

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
Your welcome Vito! Gain figures aside, I got your back!

I did enjoy the comment from the chap about “my first JA ever”! Come to California, no problem, even with one of those -- you know -- lousy Hustler mobile whips!

I understand that on the East Coast, the European’s roll in at 30/9! That’s with a Big’Ol’Beam don’t’cha know. The chap who told me that was a long time friend, who was vacationing at a family gathering in North Carolina. He was using a Mosely 2 element Tri-bander, strapped to the chimney of the family home.

Oh and 7 dBd from a 3 element Yagi? Now gall darn it that’s what I mean. It’s only two little dB’s more than the truth but, its just like fish’n -- I swear that ol’fish was THIS BIG! Its kinda like I tell my girlfriend about certain measurements, hey babe, ya want that in dBd or dBi?

Oh, and I think that it was “Inverted V’s” that work equally poorly in all directions. Lew McCoy said that!

I knew that if I waited long enough, W8JI would say something that I could agree with! His last paragraph was pretty good, and maybe even a couple of statements above it.

On a more serious note, I have no problem with calculations against isotropic radiators etc. But, don’t you think that for the greater expanse of the RF spectrum:

1) How radiation angles are going to be affected or seen by different portions of frequency spectrum is significant?

2) How ground, or even ground conductivity is going to affect certain portions of spectrum?

Probably all test data ought to be performed on 6 Meters, or maybe 10 Meters. The antennas can be put up at practical ‘free space’ consideration, and ground conditions will {probably} be mitigated. I will keep doing my tests at VHF and above, and ‘assume’ that mother nature and primarily the laws of physics work kinda close over the entire range. Kinda sorta!

 
A Vertical Antenna Advantage  
by VK5CC on May 18, 2005 Mail this to a friend!
Thanks to Tom W8JI and a few others for putting some sense and mathematical and real world knowledge into these gain claims. What hasn't been mentioned is even with 60 radials what do you think the efficiency as in actual radiated power is with a 1/4 wave vert compared to a dipole?(assuming feed point 36 ohms and ground loss 5 ohms).On 40m and up i have never been able to get a quarter wave vertical to outperform a dipole even with 40 radials and the dipole was up at 40' and when it comes to ears there's no comparison! Give me a dipole anyday!
 
RE: A Vertical Antenna Advantage  
by K2WH on May 18, 2005 Mail this to a friend!
Reply by K5DVW on May 18, 2005

All the math aside, sorry to burst your bubble but there is no way that the average ground mounted vertical antenna installation is going to give you 3 to 10 dBd... ever!

Don't take my word for it. Model it yourself with NEC, or visit http://www.cebik.com/gp/58.html for an exhaustive essay on this very topic. Be sure to check out the link for topic 1, table 3 and 4. Your exact claim is modeled there in great detail.

See ya,

K5DVW

I agree 100%. In the real world, a vertical with 50 radials will either have unity gain or slightly negative gain. Over real ground of course. The advantage of the vertical is the low angle of radiation. Maybe the author is comparing a dipole to a vertical and equating the low angle of radiation as gain over a dipole since the vertical will provide a stronger signal at a distant point.

K2WH
 
RE: A Vertical Antenna Advantage  
by K0BG on May 18, 2005 Mail this to a friend!
When I first read this article, there were no posts. I thought about adding one, but I said to myself, there are more educated folks out there who know considerably more about this subject than I do. Let them comment first, I thought.

Well, I'm remiss. Although I wouldn't have spelled it out as eloquently as Tom Rauch and some of the others, my feelings echo theirs. In my words, not Tom's, the data is trash! And anyone who takes it as gospel, needs to go back to school!

Alan, KØBG
www.k0bg.com
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 18, 2005 Mail this to a friend!
Vito,

As suggested I re-read your post... slowly, then fast, then slowly again, then fast and backwards. Seems to make more sense when I read it fast and backwards.

Either way, I read the same thing. You make some wild gain claims about verticals that just aren't fact. Maybe I am missing the point, but I don't think so.

Anyway, 6m is open to the Islands for the 3rd day in a row and I'm going to go play radio now, incidentally, on a 6m elevated vertical with 2 radials that I built :)

Ta ta,

DVW
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
Tom W8JI

Everyone is welcome to think what they want, but having measured actual antennas it sure makes me wonder where some of the stuff we read on Internet comes from!!! Some of it is really off the wall, and useless for anyone trying to learn anything useful!
---------------------------------------------------

Now please Tom show me some knowledge of how you determine the gain of a 5/8 wl vertical over a 1/4 wl vertical.

You may use 15 degrees for the vertical beamwidth of the 5/8 wl.

You may use 45 degrees for the vertical beamwidth of the 1/4 wl.

For both, the horizontal spread of 360 degrees.

Please do it mathematically in both dBi and dBd.

This should help many for the future to also gain your knowledge.

73, Vito W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by KG6WLS on May 18, 2005 Mail this to a friend!
Let me hear an AMEN.

For now I'm sticking with my dipole (or is it a G5RV?) ;-) Less noise and less money.

I live in a CC&R development, I can still string 66' of #12 stranded (without the radials that would otherwise get caught up in the lawn mower. Hi Hi). The only vertical I use is on the mobile and for the local repeaters. That's it.

.. -.-. .- -. .... . .-. . ..- ..-. .. -. . .-- .. - .... .. -.

Hope to work with all of you soon.
Until then, 73zzz

 
RE: A Vertical Antenna Advantage  
by KG6WLS on May 18, 2005 Mail this to a friend!
OOPS!!

I meant with .. - not with .. -.

Simple novice mistake :-)
 
RE: A Vertical Antenna Advantage  
by AF0H on May 18, 2005 Mail this to a friend!
Also to note, radials need not absolutely be resonant (1/4 or 1/2 wave) if mount on ir in the ground. If elevated, then sure - can't hurt. But in the ground, as most are mounted, the ground de-tunes them so quickly that they need not be measured exactly. I'm all for more radials. It's also been proven that many short radials are better than only a few long radials. Face it, the more metal underneath the ground-mount vertical, the better.

73 de
af0h - Rob
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
Well Vito, I guess they told you huh?

Ok, can anybody help me with my antenna problem? I have up this “long wire” that I was told was just about the best antenna in the world! It is at least 50 feet long, circles the eve’s of my house, and I want to use it on 160 Meters. How much gain will it have?

Oh, I heard also that a ground system was important, so I put an 8 foot ground rod in the middle of my back yard, and ran some heavy gauge #14 wire back to the house and my FT-817. Since that wire is about as long as the one under the eves, I figured that it would be best to build up sort of utility poles for it, and the run back to the house. Sound like a good DX setup?

I am thinking of getting a linear amplifier also. The one I am looking at has a single 3-1000 tube in it. I understand that I can also get one that uses a pair of 3-1000’s, and that seems better!


 
Clearing up the AM broadcast misinformation  
by N0TONE on May 18, 2005 Mail this to a friend!
As a few others have mentioned, the usage of 120 radials for an AM broadcast station is not, strictly speaking, for the purpose of optimizing performance.

I used to consult in broadcasting, and performed "proof of performance" measurements on new installations. When it came to the antenna, the FCC required an extensive, and very expensive set of field strength measurements to be made. These were to be made at ground level, at least five different distances and every five or ten degrees around the compass, and at several elevations, measured in degrees, from the ground. This requirement KILLED the financial feasiblility of most station installations.

That is, until someone (some engineering firm) made extensively detailed measurements (a helicopter was involved) and predictions of a 1/4 wave vertical with 120 ground-mounted radials, and then proposed to the FCC that this become the "reference" antenna. If a station uses 120 radials, then 95% of the requirement for field strength measurements is waived.

So, an AM station had two choices:

1) Use 120 radials - not more, and not less - and spend $5,000 on proof of performance measurements.

or

2) Use a different number of radials (for instance, 119 or 121) and be required to spend upwards of $100,000 on proof of performance field strength measurements.

Of late, I've noticed that some AM stations are now using elevated radial systems, so it's likely that some broadcast consultant has now either modeled or measured such an installation, and the FCC now accepts that also as a reference design.

For my ham usage, I've only once used 120 radials (actually 160). It's much easier to elevate the antenna and use fewer radials, and it does seem to work much better. I agree with the other poster who said that verticals get maligned because so many install them wrong. In rich, mineral-filled wet soil, you might get away without radials, but in most parts of the US you really need them.

And yes, verticals are noisier. Has nothing to do with whether they're balanced or not. It has to do with that great low-angle lobe that makes them good DX antennas. It also makes them great at picking up your neighborhood's appliances. If you elevate the vertical, you'll get rid of that noise from the nearest sources, as the narrow horizontal lobe will "fly over the top" of your neighbor's houses, as it does for the elevated Yagis that verticals are usually compared with.

AM
 
RE: A Vertical Antenna Advantage  
by W8JI on May 18, 2005 Mail this to a friend!
Now please Tom show me some knowledge of how you determine the gain of a 5/8 wl vertical over a 1/4 wl vertical.>>>

Vito, I don't use math. It can't possibly work to use math because the effects of earth are much too complex. Even modeling programs have difficulty with earth effects.

I measure it directly. That's part of what I'm paid to do.

You may use 15 degrees for the vertical beamwidth of the 5/8 wl.>>

I don't know what that means. Are you talking about the power contained in that area? We couldn't possibly calculate that without doing FS measurements.

You may use 45 degrees for the vertical beamwidth of the 1/4 wl.>>

? What does that mean??

If you are talking about power density, why would you do it over a 45 degree beamwidth with one antenna and do the other at 15 degrees? That makes no sense at all Vito.

FS comparisons are normally made at a specific angle, not an integration of a wide range of angles.

Or are you talking about the FS at a specific angle? If so, you'd have to pick the same point for both antennas. You wouldn't want to measure one at 45 and the other at 15.


I'm not sure I follow what you are saying.

By the way Vito, AM broadcast stations dropped 5/8th wave antennas like a hot rock after they started using them. The reason for that is they don't actually produce useful gain in fringe areas. They actually have more fading.

The only place we find 5/8th wave antennas in common use is amateur radio and CB radio. That's because the marketing hype keeps deluding people into thinking a 5/8th wave without a very large (several wavelengths) well-conducting groundplane has useful gain.

Of course they would do quite well over saltwater, having almost 3dB over a 1/4 wl tall vertical antenna.

73 Tom
 
RE: A Vertical Antenna Advantage  
by KG6WLS on May 18, 2005 Mail this to a friend!
He He He He!

John, could yall tell me what colur insulation I should use fer dat big nummer 14 wire on da ground? Maybe green becuz it blens in nicely wit da grass :-p
 
RE: A Vertical Antenna Advantage  
by N6AJR on May 18, 2005 Mail this to a friend!
so all this goes out the windo when I have 2 verts less than 30 feet apart, next to a stucco wall with chicken wire in it unde a 3 elle steppir and roof tower and a 4 ele tribander, and a 160 /80 / 40 slopper all in the same back yard.. now what happens..

folks most of us are in this boat, so put up what you can and enjoy the HOBBY.. any antenna is better than no antenna at all

if you put up a fan dipole vertically is ist a vert... yes but no radials are needed as it is a balanced antenna.... (look at the Gap Voyager.. its a 1/2 wave dipole with a gap in the middle, and the capicity hat on top makes it shorter, and the 3 radials on the bottom make it resonant on the top band....)

so how does the numbers add up in your back yard.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
Tom W8JI,
All of my calculations are by mathematics and the way I was brought up to use. I do not use EZNEC as with math I can solve my own problems and correct my errors.

The 15 degrees for the 5/8 wl vertical is the maximum lobe point of radiation from the antenna.

The 45 degrees for the 1/4 wl vertical is the maximum lobe point of radiation from the antenna.

No need to worry about the ground plane and can be considered perfect for this test. Then calculate later on as to earth losses.

I have had very much experience with pattern taking of many antennas during my years, rectangular recorders, etc; therefore I can also check field measurements by a receiving antenna using a bolometer in place of a non linear crystal diode and transmitting to copy a polar recorder pattern.
As a matter of fact on the f-101 fighter, I was in on the design of that antenna system used. I am not bragging, but want you to know that I am a antenna nut, or maybe just a nut.

We differ in the use of baluns and I do not use baluns, so at that point we have nothing in common, but great through ham radio we have a lot in common.

Thanks for youir post as many enjoy the reading as well as myself.

73 Vito W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by KE3HO on May 18, 2005 Mail this to a friend!
<<John, could yall tell me what colur insulation I should use fer dat big nummer 14 wire on da ground? Maybe green becuz it blens in nicely wit da grass :-p >>

I always use purple wire because it has lower losses (who would steal purple wire?) :-)

73 - Jim
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
Somebody told me that it should be green, why the heck I don't know!

Since I have it elevated in the air, from the ground rod to the eves of the house, I selected a nice shade of Robins Egg Blue.

Also, I recently discovered that that is the wire that I plugged into the SO-239 on my FT-517 -- the Robin's Egg one. The one that is tacked around the eve's of the house I connected to the chassis of the radio.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 18, 2005 Mail this to a friend!
.
WA6BFH

I am glad that we have one that knows all about antenna. That antenna is a winner and should tell us about it on Eham. Don't frighten anyone by telling the dB gain.

.:I had a good antenna at one time. I hooked s wire to my sewer pipe and got all kinds of crap. Don't work so good with our spanking brand new outhouse though.
.:
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
QSL Vito!

Well, I'm think'n that I have that sort of an antenna connection myself. I keep calling CQ {no answers yet} but, the more hours I put on the radio, the more it's power output seems to fade?

I think I'm gonna go for that pair of 3-1000 tubes. The guy told me that they are "push-pull", whatever that means, and he also said that their power supply was very healthy. Well gee, I hope so!
 
RE: A Vertical Antenna Advantage  
by KG5JJ on May 18, 2005 Mail this to a friend!
BFH:

I seem to remember years ago, that an engineer I worked with (think he was with KAAR electronics, and later some cable head-end company in CA) who did the same thing with a 1/4 wave VHF Hi-Band ground plane antenna, so the city at the base of the mountain could have access to the repeater. A simple solution to a problem, using an antenna that was already there.

Non-believers shut their yap...quickly! ;-}

73 KG5JJ (Mike)
 
A Vertical Antenna Advantage  
by W0IVJ on May 18, 2005 Mail this to a friend!
Wow! This thread is all over the place.

First of all, the sun is a good example of an isotropic radiator. It radiates equally well in all directions. If you blow up a perfectly round balloon, you could look at its surface as a pattern from an isotropic radiator. If you squeeze the balloon, it will bulge in some other direction. The same is true with a dipole and a monopole in free space. With the addition of a ground, all of the energy is squeezed out of one hemisphere, and since it has to go somewhere, it either is lost into the ground as heat or is radiated somewhere in the other hemisphere. Dbi is a good unit to use when you are comparing like antennas at comparable heights or radiation angles. Dbd can be used in the same sense as above if you don't want to keep track of the 2.14 db difference between isotropic and a dipole. Dbi in free space is a good way to compare different types of antennas.

Both horizontal and vertical dipoles and monopoles are affected by the ground. Generally the verticals are mounted nearer the ground and the horizontals are mounted away from the ground, but the ground affects both.

If you move a horizontal very close to a near perfect ground like salt water the radiation is straight up and lossy. It can be below 0 dbi if you get it low enough. As the ground gets poorer (less conductive), the losses are less. As you move the horizontal up, the gain increases and the radiation moves to lower elevation angles. In fact, as you get further away from the ground, a better ground gives higher gain and lower radiation angles but not by much. If you move the horizontal really high, it becomes multilobal.

The vertical radiator mounted on a a very good ground has good gain at a low angle (~4 dbi at ~8 degrees). If the ground is perfect the gain is about 5 dbi at 0 degrees. This assumes a good radial system so that the vertical is operating efficiently, ie, its feedpoint resitance is close to 36 ohms. If it is experiencing ground losses the feedpoint impedance will be higher. At this point I will have to disagree with Tom, W8JI, slightly, and I do this with some trepidation as he has a lot more experience with verticals than do I, and I have a lot of respect for his opinions. However, I think, that as the ground gets better the radials are less important for the vertical until you reach the limit in a salt water ground where all you need is a good ground plate or rod in the water.

Now, I like to seperate near field ground conductivity which affects the efficency of the vertical and the ground losses at the base of the antenna and consequently the feedpoint impedance from the far field ground which affects the radiation elevation angle. I have modeled (and I know this is a bad word to some of you) a vertical sitting over a saltwater lake surrounded by a poor ground. As you increase the size of the very conductive lake, you can watch the gain increase and the radiation angle decrease. For example, with a lake radius of 5 feet on a 160 meter 1/4 wl vertical, the feedpoint impedance is 36 ohms which indicates that the ground losses are low, but the gain is only 1.3 dbi at 23 degrees. A 50 foot lake radius yields 2.1 dbi at 20 degrees; 250 feet gives 3.9 dbi at 20 degrees; 500 feet gives 4.6 dbi at 13 degrees; and 1000 feet gives 4.7 dbi at 8 degrees. So you can see, it is the ground close to the antenna that affects the efficiency and feedpoint impedance, and the ground away from the antenna that affects the radiation gain and elevation angle.

Well, this has gone on too long. I hope it has been a help rather than a hindrance.

Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by KG6WLS on May 18, 2005 Mail this to a friend!
While you guys were experimenting with different antenna configurations, 6 meters opened up 03:00 UTC. Made contact with W7GJ (DN27ub), rst 579, 10 watts, on a single copper loop.
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 18, 2005 Mail this to a friend!
Yes, KG5JJ -- it was certainly not a unique idea on my part -- only common sense in the way that Ground Planes work; and as Vito has described!

WLS had the right idea though, we should have all been on 6 Meters!
 
A Vertical Antenna Advantage  
by AI2A on May 19, 2005 Mail this to a friend!
Hi Vito,

First, I agree that verticals are effective antennas. I also agree that fewer than 120 radials will radiate a signal. I agree that there are probably diminishing returns at some point when adding more radials. Yet, I will probably still install a planned forthcoming Hygain AV18HT with 120 radials.

Second, please allow me to respectfully disagree with your math and discussion on dbi / dbd. Dbd or dbi BOTH are decibel units. The dbd is used when a comparison is made against a dipole at or above 1/2 wavelength in height - whereas dbi is used when a comparison is made against an "isotropic" radiator - in the vacuum of free space.

My yagis (mounted at least 1/2 wavelength in height) yield better results than my 1/4 wave full sized verticals with their 16 radials (ground mounted). These results seem to hold true regardless of DX or more local signals - about 90% of the time. I also compare against dipoles and various other antennas at my QTH.

My observations seem to be in direct conflict with the explanations contained in your statement. I too use and appreciate verticals - we can definitely agree on that.

Until I save up a bunch to install a 75 meter yagi - I will continue to use verticals! Email me for the address to send funds if you want to do a side by side comparison - vertical vrs yagi (on 75M)

Good Luck, 73 and Best Regards,

David Clark, Ai2A
Greenwood, IN 46143
ai2a@yahoo.com

 
RE: A Vertical Antenna Advantage  
by WA2JJH on May 19, 2005 Mail this to a friend!
I get plenty of DX with verticals. I think the reason
why verticals have a bad reputation is because people either use a couple of radials for ground or elevated roof installations.

Some purchase used verticals. I saw a 12AVT that had so much dirt and oxide on it. I saw one case where the connector is so oxidised, it had diode like activity.
This will create IMOD before the transceiver.

People sometimes build the vertical wrong. They did not follow instructions.

Some people buy cheap 5/8th 11M verticals. One has
to cut the radiator down and remove the internal lightening protector. If you leave the lightening protector in....You have zero performance on 80 and 40M. One also cannot get below a 2:1 SWR on 20M.


Monoband verticals can be used to make a "phased array" with 2-4 verticals. Then you have some real gain over a dipole.
 
A Vertical Antenna Advantage  
by N0AH on May 19, 2005 Mail this to a friend!
Having the opportunity to operate at a couple of major contest stations using yagi antennas on 40 and 80 meters, the yagi's had the majority of times where they took advantage of various angles of receptions and transmissions to accomplish more QSO's versus vertical antennas, be it a 1/4 wave monoband, or a multiband system. They yagi's just heard signals earlier in the night or morning that were just not there on the verticals.

That said, it was not that uncommom for the monoband 1/4 wave verticals to outperform the yagi's maybe 5-10% of the time. You just never knew until you tried. As others have mentioned, there are just too many Earth variables to make this a black and white science on paper. 5-10% may not sound like a whole lot, but in a contest situation, it is.

For those of us without the resources for 40 or 80M yagi's, Vertical antennas are awesome and a lot of fun. Without radials, I was able to work a lot of the United States on 80 meters using the Hustler 5BTV from my father-in-law's back yard in northern France. Of course this was only at sunrise so using the grayline helped.

From Lord Howe, I brought a multiband Cushcraft AP8A vertical with 20 radials and worked well over a 1,000 stations in the United States at their grayline on 30, 40 and 80 meters with only 100 watts on my FT-900.

Living in the USA, your call sign is common place so that while it might be heard, you don't always get the response on your CQ. But trust me, go to a rare DX spot, and your vertical will get an added boost of 30 DB!

You never know what conditions will bring. My ideal station for a small lot is a 10-20 meter beam like a T-6 log periodic or Cushcraft MA5B, and a 10-80 multiband vertical like the Hustler 6BTV or without 80M, the Cushcraft R8. This combination will allow for changing conditions for signal angles on the high bands and let you have good luck for DX the low bands.

As for the issue of radials since they keep coming up....I keep getting caught with this issue over the years myself. What I've learned is to just add as many as you can in your backyard and be happy. My rule of thumb is to add at least 20 and after 60, you run into the law of diminishing returns.

But as one noted engineer and world class ham told me, Dave-AA0RS,if you want to build the ultimate antenna, why build it then leave the race car tires off? In other words, put the 120 radials down if you have the chance.

73

Paul
 
RE: A Vertical Antenna Advantage  
by K5UJ on May 19, 2005 Mail this to a friend!
<<<By the way Vito, AM broadcast stations dropped 5/8th wave antennas like a hot rock after they started using them. The reason for that is they don't actually produce useful gain in fringe areas. They actually have more fading.>>>

That's right--In the 1930s 5/8 w. towers were begun to be used by what were or became the 1-A clears in the U.S. (50 kw medium wave bc stations with unlimited day/night service nondirectional on unoccupied channels). It was discovered that while a 5/8 w. tower lays down a nice flat wide-ranging groundwave, it also has a high angle lobe that at night would come back down at about 200 mi. out and cancel the groundwave resulting in a ring of fadeout around the station. It was determined that about 194 degrees of height either eliminated the high angle lobe or lowered it enough to go beyond the groundwave and eliminate the cancellation (I can't remember which) but still offered some of the 5/8 w. type groundwave coverage (i.e. best compromise between 180 deg. and 5/8 w.). Most so-called 1/2 w. towers are around 190 to 200 degrees for this reason today. I am in awe of engineers of the 1930s for having figured this out without modelling software, computers, calculators etc. They only had slide rules, measurement equipment and graph paper.

 
RE: A Vertical Antenna Advantage  
by W9OY on May 19, 2005 Mail this to a friend!
>Everyone is welcome to think what they want, but having measured actual antennas it sure makes me wonder where some of the stuff we read on Internet comes from!!! Some of it is really off the wall, and useless for anyone trying to learn anything useful!

73 Tom<

True enough

So what are the vertical antenna advantages? So far in this thread I haven't been able to figure out what is off the wall and what is real.

I need 120 radials because the FCC charges broadcasters 100k for POP if you use 60. But 15 is enough cause after all we are just hams... Are those 120 1/4 wave radials or 1/2 wave radials or what? A 1/4 vertical with 2 radials at 27 ft works as good as a ground mounted with 3000 radials? Or is that 13ft? A dipole works better except when it works worse. 5/8 th wave verts loose their snot unless used over the Pacific ocean. Broadcasters dropped them 'cause their ground wave coverage stinks. What's that got to do with working someone in the Indian ocean? Verticals are more noisey except when they are quieter. The EZNEC vs Math debate, what the heck is that all about? Both are just figments of someones imagination. I remember I built a model of a 427 corvette stingray when I was a kid. It never went faster than zero MPH. I don't think anyone ever worked Iran using EZNEC. Square degrees? Is that like a PhD squared? .35 WL liftoff angles? Call NASA. Tuned 1/4 wave radials laying on the ground or are those tuned 1/2 wave radials? Where do you feed tuned 1/2 wave radials anyway? In the middle or at the end? If grounds that are elevated are so much better then why do you need about 50 ferrite beads to get RF off the coax? My dirt is only a 2 on the FCC map? Guess I need to seed about 30 square miles with sea salt.

>Everyone is welcome to think what they want, but having measured actual antennas it sure makes me wonder where some of the stuff we read on Internet comes from!!! Some of it is really off the wall, and useless for anyone trying to learn anything useful!<

I talk to the boys down on 80M who have 310 plus countries and they are all running vertical 4 squares. Some are full size 1/4 wave, but many are only about 40ft tall top loaded. Most are running about 16 radials under their antennas. Yet these guys have worked just about every thing that there is to work on 80M. Why are they running these antennas? Because in the horse race they are not competative unless they are running these antennas. The boys with the dipoles are also rans. Some have run high dipoles in the past and have abandoned them in favor of the vertical beams. To a man they are now running vertical 4 squares. There may be a lesson in there somewhere.

I don't know anybody who is serious about 160 that is running a dipole as their primary DX antenna. Almost every one I talk to is running some kind of Marconi or vertical. I listen to the pile ups on 40M and except for the guys with beams at 100ft, the guys running the verticals always seem to be right in there making the contact in one or two calls. My experience is my verticals are lower in noise pickup than my flat top. I live out in the boonies so I don't have a lot of industrial noise to deal with but non the less my verticals tend to be quieter.

So i'm not sure what this thread is really about. I'm not sure what the wives tales are and what the reality is. It's hard to imagine a little pipe sticking up out of the ground with anywhere from 0 to 5000 wires surrounding it could attract so much lightening.

73 W9OY

 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by KG6WLS on May 18, 2005 Mail this to a friend!
While you guys were experimenting with different antenna configurations, 6 meters opened up 03:00 UTC. Made contact with W7GJ (DN27ub), rst 579, 10 watts, on a single copper loop.<

That's real ham radio. And it opened a lot earlier than 0300 UTC. Here in Los Angeles, I got on six about 0030 UTC and immediately worked:

W5GAI EM10 TX
W2GFF/4 EM60 FL
K4QI FM06 NC
W4LK EM93 SC
KG4RXF EM64 AL
KG4PAC EM64 AL
KG4PSR EM65 TN
K5DNL EM15 OK
K4YMQ EM63 AL

...all in less than 30 mins, and mostly on 6m CW.

Interesting, the band was "packed" below 50.100, where only CW is allowed, and not nearly as packed above it. CW made for easier contacts. I called one CQ on 50.096 and ran six guys in a row there.

Oh, to get back to "verticals:" One observation last night on 6m...with every station I contacted via Es on six, I tried switching between my horizontal beam and my vertical omni, just for kicks. Couldn't really hear *any* of them clearly on the vertical, but most were "59" or thereabouts on the horizontal.

At least I could spin the thread back towards verticals, somehow... :)

WB2WIK/6
 
an example of a station using verticals  
by KZ1X on May 19, 2005 Mail this to a friend!
WWV uses elevated-radial verticals.

They work pretty good, too!!

I think it's great that an 82 year old guy is still playing with antennas (and using computers). I hope when I get to Vito's age (in 40 or so more years) that I will also be capable of staying at least somewhat currrent. Who knows what kind of newfangled widgets we'll have then?

That said: the Federally-funded Livermore Labs research that led to the NEC-2 model underlying EZNEC is nothing to sneeze at, nor is the EZNEC Windows program itself. I use it all the time! Vito would be doing himself a great service by downloading the demo version from W7EL and plotting out some of the verticals he is mentioning.
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
W9OY, so why don't you conduct a test?

I suggest, if you’re into HF, use 10 Meters. If your into VHF, probably best to use 6 Meters (pssst, because then you can scale your results either down or up)!

On 10 Meters a Quarter wavelength piece of copper pipe would be 98.87 inches long to be resonant at 28.400 MHz. You can build a base insulator out of white PVC pipe, or ABS pipe in about 5 minutes. Set this puppy up in a clear field with nothing near the antenna for a radius within at least 34.66 feet (pssst, that’s one wavelength {with no consideration for velocity factor}.

Make a number of radials of some convenient AWG wire size, they should be 103.87 inches long (or twice that for a half-wave, or 259.68 for 5/8ths, or 311.61 for 3/4 wavelength). I would start with two, measure the radiation resistance, and then keep doubling them -- taking measurements each time.

On 6 Meters the pipe would be 55.05 inches for 51.000 MHz. Quarter-wavelength radials would be 57.80 inches long.

On 6 Meters you can probably also assess launch angles by using various repeaters as signal sources. If you try to do that on HF, get your data from WWV for the height of the F-layers (and E-layer), get out your Slide-rule or calculator etc, find someone with a signal generator so that you can calibrate your S-meter in dBm (pssst, don’t forget to turn off the AGC), and there you go (Oh, do pray for good data from WWV)! If you use 6 Meters, you can corroborate your data on 2 Meters!

Go for it!
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 19, 2005 Mail this to a friend!
I like verticals, I've used them a lot over the years. Being a cw op, I've found that verticals were effective dx antennas in all cases. Of course they are capable of fair to excellent performance depending upon how much work you're prepared to invest. Sorry to say, the author of the article is wrong about gain. A 1/4 wave over an excellent ground plane is capable of about .5 dbi; a half wave about 2 or so dbi and a 5/8th wave about 3 or so dbi. Thats reality!

That said, I wouldn't let anyone discourage you from experimenting with half wave and 5/8th wave verticals no matter how much they insist that the inherent theoretical gain is unobtainable unless configured over a perfect ground plane. It not true!

I've experimented with different grounds over the years, everything from ground rods to elaborate radial systems, both well inland, in the desert and alongside the ocean and even on islands.

In 1980-81 I put up a 43 ft. high vertical to act as a 5/8th wave on 20 meters, .31 wavelength on 40 and .16 wavelength on 80. In its first configuration I had fifty 100 ft. radials under it. I later cut them in half and made them one hundred 50 ft. radials. I really couldn't tell much difference between the 2 radial systems, but to do so I'd have had to have been able to compare them side by side in an A-B test. I was able to determine that, time averaged, on 20 meters, on the Charlotte,NC to Calif. path, that my signal was about 1 S unit down from a trap tribander at 70 ft. high. Thats pretty consistent with the ground reflection gain of the tribander, a horizontal antenna. Although I read repeatedly that verticals don't have any ground reflection gain, I think that really is meant to be understood as below the pseudo-Brewster angle. This was by far the most impressive vertical I ever used and worked well even on 40 and 80. On 20 meters it really was evident that the lobe was narrow and squashed compared to a 1/4 wave vertical. The first skip zone was a very well defined 1000 miles and any signals heard inside of that were weak. This was the first antenna I ever had that I heard lots of Europeans well above S9 on 20 meters, even 10-20-30 db over. Prior to that I had never had a 20 meter horizontal wire over about 1/2 wave high. No comparison. My ground using the 5/8th wave was "below average conductivity", 2-4 or .002-.004 ms.

I would strongly recommend Capt. Paul Lee's vertical book, also W6SAI's. Half wave and 5/8th wave verticals can have gain and desirable lobe characteristics, even in amateur applications, with good ground screens/ground planes.

Modern research now reveals that verticals in the air at fairly modest heights with 3-6 radials can provide performance that is very respectable when compared to near ideal ground radial systems. This looks like its worth exploring. Verticals want to work and do!
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Hey, WIK -- be cool or your going to have Caity on my a** again!

Every serious 6 Meter Ham should have a vertical omni-directional antenna! It’s simple, cheap, and there is NO REASON not to have one!

It is good too to have a horizontal antenna, AND A COAX SWITCH or relay!

Steve, what is your noise level in your area (HF Fan’s ignore this question -- 6 Meter Noise Floor is a different consideration than the noise floor across the HF spectrum)?
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!

>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!

>find someone with a signal generator so that you can calibrate your S-meter in dBm (pssst, don’t forget to turn off the AGC), and there you go<


Receiver S-meters don't work without the AGC turned on. What they indicate is AGC voltage.




 
RE: an example of a station using verticals  
by WA1RNE on May 19, 2005 Mail this to a friend!
Bottom line: For some, there is a tendency to strive for absolute perfection - or else the project isn't worth completing.

Installing 120 radials for a ground mounted vertical is great if you can pull it off - but it isn't necessary to work DX.

For the majority of us, 4 to 8 radials with an elevated feedpoint will work just fine, be it a 4BTV, 5BTV or a full size homebrew 1/4 wave vertical.

BTW, considering that most AM broadcast verticals are ground mounted and the station owners are counting on an antenna with the highest attainable efficiency and coverage pattern to make money, wouldn't that explain the need for and desire for so many radials in a commercial application?

Not really an apples to apples comparison with Ham Radio is it??

73, Chris
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Steve, most radios these days take S-meter drive from a 'log driven' output on the I.F. chip.

Even your ancient FT-736 does this!
 
RE: an example of a station using verticals  
by WA6BFH on May 19, 2005 Mail this to a friend!
Chris, for me 160 Meters is a novelty band (give me a minute to change into my asbestos shorts)!

It can be fun to get on and check out but, any range of RF {energy} that conducts itself better through dirt than it does through the air, is just sorta strange!
 
RE: A Vertical Antenna Advantage  
by AL2I on May 19, 2005 Mail this to a friend!
Having run an elevated vertical (with 2 radials) in the middle of a city, I can testify that there is a LOT of noise that is vertically polarized. Even if I couldn't hear them so well, other stations could hear me. I was running 35 watts max.

This explains why so many vertical guys are all talk and no listen... I talk to a lot of vertical guys when I run a KW, but when I run barefoot, it seems like most QSOs have a dipole, beam, or horizontal loop at the other end.

For my money, on the low bands, large horizontal loops seem to be the best stations, and I am planning on putting up my own. Interesting discussion here. I am surprised at the tension however.

73,
Dave/al2i
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!
Steve, most radios these days take S-meter drive from a 'log driven' output on the I.F. chip.

Even your ancient FT-736 does this!<

FT-736 has no way to shut "off" the AGC, it's always active.

In my HF rigs (all four of them), if you turn the AGC "off," the S-meter goes dead.

WB2WIK/6
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
On your FT-736, YOU DON'T NEED TO TURN OFF AGC, the meter will read all signals on a true log basis (true Log S-meter), no matter what mode etc.

I used to use mine to take antenna data out on Cuddeback Dry lake. That was one of the advantages of that radio! My TS-680 would start to go into AGC compression at about the time signals hit S8, so further data was meaningless!
 
RE: A Vertical Antenna Advantage  
by W8AD on May 19, 2005 Mail this to a friend!
K5UJ,

You're right on about AM broadcasters using 5/8 wave towers. That performance actually verifies why 5/8 units are great for ham DX.

My friends in the high end AM broadcast business will tell you the BIGGEST reason for the demise of the 5/8 AM towers is the material and construction costs of such a tower. Can you imagine those costs of putting up a tower 5/8 wave high on AM frequencies, compared to a 1/4 wave design? Do the math. It's staggering!

Some years ago, I ran many comparisons on 20 meters with a commercial 3 element triband beam (I know, not very good) at 60 ft. at my QTH, compared to my neighbor's 5/8 wave 20 meter vertical. I'm embarrased to that his 100 watts often equalled or beat my kW. The DX station used to say, "OK Don, turn on your amp now" and I would have to say "it IS on".

Look at Cebik and you'll see it's not the gain, or lack thereof, that makes the 5/8 an important antenna. It's the low take off angle for DX. About 14 to 16 degrees for the 5/8 compared to about 22 degrees for the 1/4, according to his data at <www.cebik.com/gp/58-3.html>. I know ground conditions make everything variable at different QTHs but don't sell the 5/8 w design short.

Don, W8AD
 
RE: an example of a station using verticals  
by W6TH on May 19, 2005 Mail this to a friend!
.
WA6BFH John,

I went through all listings on this post and have not found two that agree with radials, the amount of.

This post was set for the determination and comparison of the isotropic gain of a 1/4 wl vertical versus the 5/8 wl vertical. Even those using EZNEC have diagreed with one another in a case or two. EZNEC is just software, but I enjoy computing for my own benefit as I am gifted and capable to do so.

I have cancel, abolished two posts as it will again turn out to be a animosity ham radio gathering.

I admire your knowledge, when you admit others are wrong, you do come back with a teaching method as to correct and educate. Whether, theory, math or practicable knowledge.

73 W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by K8DXX on May 19, 2005 Mail this to a friend!
Interested in your comments about the 40 ft, top loaded vertical. I currently use a GAP Voyager IV (half wave vertical dipole for 160-40) and like it very well (45 ft fall, capacity hat for loading on 80, quuieet listener, broadbanded, etc.). Maintenance has always been higher than acceptable and due to local valdalism to guy ropes, is becoming too much.

So... my question. Do you or anyone here have experience with the MFJ 1792 80 - 40 meter vertical? It is 1/4 wave on 40 and top loaded using a capacity hat on 80. I plan to ground mount it in place of the GAP. I'll install as many radials as possible; estimating 8+ 66 footers for 80 and 16+ 33 footers for 40. Any opinions?

As to radials, do you experts recommend insulated wire or bare copper? I intend to "staple" the radials to a close cut lawn and let the grass grow around them. This approach has worked well for me and avoids the effort of burying, slitting the turf or whatever.

73 & Great Thread,

Bill / K8DXX
 
RE: an example of a station using verticals  
by WA6BFH on May 19, 2005 Mail this to a friend!
Well lets see now, a 5/8ths wavelength vertical antenna for 10 Meters (28.400 Mc) would be 247.18 inches, or 20.6 feet.

I like to use copper pipe for two reasons:

1) You can pretty safely assume it is the best conductor you can get (that is practical).

2) You can easily solder to it, low resistance connections are paramount!

3) You can easily assess the high current points for various radiator designs (you do this by running power into the antenna, and seeing where it gets hot).

Copper that tall would be a little unstable mechanically but, I’m thinking, a 10 foot length of ¾ inch, and 10.6 feet of ½ inch diameter.

5/8th wavelength on 6 Meters would be 137.64 inches, or 11.47 feet -- much easier to build!

Of course the radial dimensions I used before would work here just fine!

Also Vito, thank you for the nice compliment! My idea is though that these are simply the things that Ham’s should do. The first gift my Elmer ever gave me was Bill Orr’s ,“VHF Handbook” the next was “Antennas” by John Kraus. At the time the math was kind of beyond me, it probably in cases still is. Yet I think, these books describe the very scientific heart of Ham radio. That’s my story, and I’m stick’n to it!
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
K8DXX, I think that I would recommend bare copper. The reason for this being that it will tarnish, and the tarnish oxidation is the best dielectric you can get!

I recall some data taken from microwave "G-line". G-line is a single conductor feed-line, with funnel shaped cones at either end (the cones flare out to ultimately match the impedance of air).

Anyway, it was recorded that as the newly installed fresh wire of the G-line oxidyzed, the G-line became less lossy!
 
RE: A Vertical Antenna Advantage  
by KG6WLS on May 19, 2005 Mail this to a friend!
WIK,

I agree with you on the vertical vs. the horizontal on the 6 meter opening last night. I use a Comet GP 15 tri-bander for the local nets here. After our net was over ( actually I kind of snuck out early) I switched back and forth with both configurations. More noise on the vertical and a little more tweaking with da knobs on da radio.

Should have turned on the radio sooner yesterday and pushed the power level up. Maybe I should get an amp, right? That way the amp will be the first thing I turn on when I get in the shack :-)



73

 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!

>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!
On your FT-736, YOU DON'T NEED TO TURN OFF AGC, the meter will read all signals on a true log basis (true Log S-meter), no matter what mode etc.<

That's not quite right. On FM, the S meter is driven by the limiter and provides meaningless information. The FT-736R S meter "pins" at about 50uV on FM, and connected to a Stationmaster (at my home) on 2m, half the repeaters in southern California pin it.

It's much better on SSB and CW, though. In fact, it's pretty darned good, and remains pretty good band-to-band on 50-144-222-432 MHz (I don't have the 1296 MHz module, but it might be good there, too).

I fixed the overload problem in the 432 MHz module, also -- an easy fix, increases BDR from about 70 dB to >100 dB.

WB2WIK/6
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!
Hey, WIK -- be cool or your going to have Caity on my a** again!

Every serious 6 Meter Ham should have a vertical omni-directional antenna! It’s simple, cheap, and there is NO REASON not to have one!

It is good too to have a horizontal antenna, AND A COAX SWITCH or relay!<

I do, and use it.

>Steve, what is your noise level in your area (HF Fan’s ignore this question -- 6 Meter Noise Floor is a different consideration than the noise floor across the HF spectrum)?<

Usually very, very low; although I can point towards thunderstorms and hear them, and if I aim towards the sun on the horizon (E at sunrise, W at sunset), I can hear that, too. But otherwise, the "average" noise level is pretty much nothing.

WB2WIK/6

 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
You can hear "Sun noise" ON 6 METERS with an FT-736? You must have the best frick'n FT-736 in the world man! Truly magical! That puppy defies the laws of physics!

Uh, ya might want to read Lou Anzios studies on atmospheric noise levels sometime. You know, relative to Frequency/Kelvin temperature!

I will have to dig up my old service manual for the FT-736. I'm certain I remember that the meter is driven essentially by its own receiver, that is part of the I.F. As far as the S-meter is concerned, the radio does not know what mode the radio is in.

I am glad, I guess, that you live in a repeater area that can 'hard limit' you’re FT-736! Since it only has about 20 dB's of limiting, that takes quite a bit of signal!
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by KG6WLS on May 19, 2005 Mail this to a friend!
WIK,

I agree with you on the vertical vs. the horizontal on the 6 meter opening last night.<

Yep. Despite rumors to the contrary, I almost always find horizontal polarization to be better for VHF, even for sporadic-E propagated signals. I do have a vertical I can instantly switch to, and the vertical always works better for FM-repeaters, no matter where they are. The beam works better 99+% of the time for SSB-CW signals, no matter where they're coming from.

Guess you've found the same thing.


 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!
You can hear "Sun noise" ON 6 METERS with an FT-736? You must have the best frick'n FT-736 in the world man! Truly magical! That puppy defies the laws of physics!<

No, it doesn't. I can hear sun noise on every band. The peak is more pronounced higher in the spectrum because antenna gain is higher and beamwidth narrower.

>Uh, ya might want to read Lou Anzios studies on atmospheric noise levels sometime. You know, relative to Frequency/Kelvin temperature!<

Who's Lou Anzio? I've never heard of him.

WB2WIK/6

 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 19, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!

Uh, ya might want to read Lou Anzios studies on atmospheric noise levels sometime. You know, relative to Frequency/Kelvin temperature!<

Do you mean Lou Anciaux, KG6UH (ex-WB6NMT)?

What would he know about this? I've met Louis many times when he used to live in San Diego and he isn't a scientist, but he is now a retired Navy captain and I'm jealous.


 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Interesting! Lou Anzio is a rather prominent voice in VHF DX'ing, sort of what Wayne is to VHF contesting. Lou is just a bit more left brained, not that I would deem to count that against him!

I'm not surprised that you might hear sun noise on 70 or 135 cm (although even that would be good for the FT-736) On 2 Meters, it would be difficult (very for the 736), and on 6 Meters virtually impossible!
 
RE: A Vertical Antenna Advantage  
by W8JJI on May 19, 2005 Mail this to a friend!
The 2 verticals that I have used , an HF9V and a 31ft aluminum pole with a remote mounted coupler at its base both mounted on the roof with 3 to 4 radials for the bands that I enjoy most 40, 20, 17, and 12.

It has been to my suprise that on 20 thru 12 meters my verticals produce about the same signal strength at the receiving station as other stations in my region that are using 2 element quads or 3 element yagis.

And on 40 meters it is always a suprise, the verticals have each produced BIG signals in the less than 400 mile range but can also work som very decent DX as well.

All done with about 125 watts ssb.

Maybe I'm just lucky ?

( I think getting the HF vertical OFF of the ground is key! )
 
RE: A Vertical Antenna Advantage  
by W6TH on May 19, 2005 Mail this to a friend!
.
Steve, what you really need is a 4 phased helix array.
With the material we have today in hardware stores, it can be easily built. You can if you want a big project go for the parabola or parabolic reflector, terrfic amount of gain. Why settle for the simple antennas as yagis, quads and verticals?

Become the top of the line ham. John has the book material for your construction I am sure. If not, I can design one for you at no cost.

73, Vito W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by W9OY on May 19, 2005 Mail this to a friend!
In response to WA6BFH

Actually I have done it. I've run the experiment on 20, 30 and 40M comparing 1/2 and 5/8 wave verticals using 1/4 wave verticals and a 138ft openwire fed flattop doublet at 60ft as reference. I also compared a full size 80M 1/4 wave vs a 1/8 wave loaded 80M/1/4 wave 40M antenna (a Butternut HF-2V). Each was tested over the same ground screen, and I was able to A/B either the 1/4 v the 1/2 v the flat top, or the 1/4, v the 5/8 v the flat top.

Across many comparisons at many distances my experience is 5/8 is better than 1/2 is better than 1/4 is better than 138 ft flat top on paths of about 4000-5000 miles or better. On all the verticals the noise is around S-0 to S-1 and on the flat top the noise was S-3 to S-5 typically. With higher noise levels on 80, and going down with increasing frequency. The differences in performance were small but definitely noticeable, typically around 1-S unit between the 1/4 wave and the longer verticals, and between 1 and 3 S units between the verticals and the flat top.

My final set up to date is 1/4 wave full size on 80M, 1/2 wave on 40M, 5/8 wave on 30 and 5/8 wave on 20. I also use a 160M inverted-L with the vertical section of 60ft. I took the Butternut down and put it back in the garage. Each of these antennas are fed separately from a remote coax switch and each has very little interaction with any of the others. The 160 uses a hairpin coil for matching and has about 120 khz bandwidth. The 80M antenna uses no matching network. Each of the high impedance end fed antennas has its own parallel or L network. The ground field is 32 50-60 ft radials with another 10 100ft radials, as my property allows. My property falls in the #2 area on the FCC ground conductivity map. Since last October 27th when I put up the Butternut HF-2V and put down the first 4 radials, I have worked DXCC on 20, 30, 40 and 80, and have 70 countries on 160, with just under 200 countries over all.

I have used up to 100 radials in the past and have not found much difference between 30 and 100. I have compared elevated verticals using 2 to 4 radials in the past, and have not found them to be superior to a ground mounted vertical with 12 radials. If you put up 12 or more elevated radials, I don't see that as easier to erect than just going with a ground mounted antenna.

The 80M full size is superior to the 1/8 wave loaded antenna on this band by about 2 to 3 S units. The full size 80M is about the same as a 55ft wire T style Marconi I put up as an interim experimental antenna in some trees before I bought the aluminum for the full size vertical. If you want a cheap well performing vertical for 80M and you have a couple of trees, make a T Marconi wire antenna, fed against 30 or so radials. You can also use this antenna through a tuner on 30M, and it works amazingly well. I matched this antenna with a hairpin coil. In one iteration of my experiments, I had up wire verticals for 80, 40, 30 and 20 with the Inv-L on 160. It was very low profile and worked very well. The supports were 2 60ft pine trees 85ft apart with a rope strung between the 2 tree canopies. The wires were supported by the rope. The ground screen was about 1/3 of the way between the 2 trees.

Now I am not saying any of this is gospel. Nor am I saying someone else will not have a different experience, but this is my experience over several decades of playing around with vertical antennas. They are real world experience, and have nothing to do with squared degrees, or wives tales or FCC proof of performances. Neither are they publishable in the proceedings of the IEEE. I have had a blast playing around with these antennas over the past 6 months. I don't have a 5/8 wave tower on 160 like Tom does, nor will I ever have such a tower. I will never have even a ¼ wave tower on 160. Even though I bought my piece of property out in the boonies so I could raise a few antennas, the county passed a county wide covenant limiting tower height to 100ft unless you apply for a variance, so I'm stuck at less than 100ft like a lot of my fellow hams. I think reporting this experience has some merit since there are many hams who can get up a 60 ft aluminum pipe, or have a few trees that will support T style Marconi wires, with a 50ft radius patch of ground for radials. I tried a few variations of using some kind of multiple feed system for these antennas and found that independent custom built feeds with a remote coax switch was the way to go. Putting up a 60ft aluminum pipe is less expensive than putting up a tower.

I happen to have 4, 65 or so foot trees separated by 70ft in a square on another part of the property (at least until the next set of hurricanes blow though). Any idea what my next project will be? I’m building the test equipment (N2PK-VNA), so I can then build the phaser as you read this. There is still a TON of fun to be had in ham radio.

73 W9OY
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!

Vito, helix or “Helical” antennas are seldom used below 2 GHz, maybe by some radio astronomers. Afterall, that is what our friend W8JK invented them for!

Steve probably has up a better VHF/UHF antenna system these days than do I. I’m keeping a low profile, in this real estate market! Besides, I can do much better ‘mountain top’ portable, with more modest antennas, than anything that I might do from Anaheim with a 60 foot tower etc.

Steve, I believe you are right. Sorry about the spelling. I first met him in 1969 when he gave a presentation at the ARRL Southwestern Division Convention. His talk was presented on his findings of the time, pursuant to the use of ‘low noise’ amplifiers for VHF/UHF. J-FET’s were becoming common then. The military was aware of GAsFET’s, nobody else was then thinking of NMOS or HEMPFET’s yet.
 
RE: A Vertical Antenna Advantage  
by K7PEH on May 19, 2005 Mail this to a friend!
W6TH says...

"Please do it mathematically in both dBi and dBd."


What? Isn't the difference between dBi and dBd a constant, something like 2.15 or whatever. Why not do the math in one and merely add or subtract the constant to get the other.
 
RE: an example of a station using verticals  
by W6TH on May 19, 2005 Mail this to a friend!
.
KZ1X Stephen,
.

Thanks for your kind remarks as to an 82 year old man.

I still have all of my marbles and keep up to date.

Reason that I am not interested in the EZNEC, I am a trouble maker and trouble shooter. I will look for errors in mathematics such as Algebra, Trigonometry and even calculus, such as I use in the John D. Kraus antenna books.

I am in enough hot water as it now stands with just simple calculations of antenna gain in dBI, using a globe called a isotrope. Keep smiling and happy trails Stephen.

73, Vito W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 19, 2005 Mail this to a friend!
.
K7PEH

What? Isn't the difference between dBi and dBd a constant, something like 2.15 or whatever. Why not do the math in one and merely add or subtract the constant to get the other.
-------------------------------------------------------

To find the dBi of a horizontal or vertical antenna, it is the normal thing to do is to use the E and H planes for calculating gain in Isotropic.

To change dBi to dBd over an isotropic you must use the base 10 of the log.

1.64 dBi is the gain of a dipole with the use of 70 and the 360 degrees. To become in dBd over a isotropic the log base 10 comes into view.

The log of 1.64 dBi is 0.214 times 10 = 2.14dBd over a isotropic. I will now compute a dipole for you:

70 times 360 = 25200 (41253 divided by 25200 = 1.63dBi.)

Log of 1.63dBi = 2.14dBd over an isotropic.

Does this make sense to you? The 70 is the E plane and the 360 is the H plane.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by K7PEH on May 19, 2005 Mail this to a friend!
W6TH...

I am not sure I followed your calculations or what you are saying. And, I have degrees in Physics with advanced degrees in Math. I know, there is still magic with ham radio, right?

In any event, it is common to compare antenna gain with either a dipole (dBd) or an isotropic (dBI) as a single fixed number. To choose a given direction via phi and theta (spherical coordinates) is not common and that seems to be what you are doing or maybe what you are trying to say but I just don't follow.

Oh, I have studied Kraus from cover to cover as well as Stutzman & Thiele and also Balanis. By the way, as for antenna theory, Balanis is my favorite (sorry, W8JK, RIP).

But, in spite of all that book learning, I am still a novice when it comes to down and dirty antenna theory so I will bow to most everyone else. However, I just don't understand what you are saying.

PEH
 
A Vertical Antenna Advantage  
by WA1RNE on May 19, 2005 Mail this to a friend!

One last comment for you, Vito; (like you need more)

Tell me this article and all the posts thereafter (most) would not have been more fun if they were discussed on the air instead of ARoI??

This "vertical" topic would attract a bunch of people on a Saturday afternoon on 75, 40 or 20.

Propogation on 40 has been decent lately. My Full Wave loop is down at the moment, sitting in a heap in the yard and I still heard 6's coming in 4-5 around 9 PM EST.....

No fan dipole discussions allowed.......(hi)

73, Chris






 
A Vertical Antenna Advantage  
by N8BEG on May 19, 2005 Mail this to a friend!
I appreciate anyone who likes to "think thru" thier amatuer hobby and especially when it applies to antenna's. I realized years ago that the antenna was the most important part of the station as far as recieving and transmitting "efficiency" was concerned.

So, I studied antenna design. Pretty deeply. I built a ton of em. Verticle, Horizontal. Loops. Beverage. Sterba ( yeah, believe it or not, Sterba ). Long wires..rhombics....you get the picture.

Long story short. For the HF bands I operate ( 80 to 10 meters using 100W max. ), and I have settled on this antenna. A 135 foot flat-top dipole fed with home made 550 ohm open wire line at 45 feet thru a tuner. It is strung up east to west at my Northern Michigan home. It works as well as the best of any other of the antenna's I have built and better than most. Simple, but true. I never found the "antenna advantage" in some secret design.

You can spout off all the technical properties of different designs, but in real life, surrounding properties ( ground, trees, buildings etc...) will change all of that "textbook" stuff.
Imperical properties are nice but the reality of performance is greatly different.

We talk about ground and we have a mental picture of the flat earth below the antenna. Not so. Ground is thick and runs ( electrically ) very deep and depends greatly on the composition, moisture content and geometry of the soil. Verticles are most "finicky" about this. They are really just a dipole
stood up verticly. The other half of the dipole
is the image under ground. The earth being lossy and variable is why we have to bury radials to bring that image conductor closer to the surface. Vericals are more susceptible to local man-made noise, in my experience.

Anyway, we talk of lobes and angles and gain all as if it is fixed by antenna design. Its not. Not on Earth, anyway. The terrain around the antenna is a major part of the design. Our projected lobes and gains are just "mental" images. In reality its all over the map. Propagation changes everything even more.

I won't even start on feedline losses. This is greatly ignored.

Building or finding the perfect DX antenna? Its pretty futile, indeed. If you have good results at your location with a vertical, that's fine. It may not play out as well at another QTH. And its performance will vary over time. With my dipole, I work the worlds DX, bust thru pile-ups. I work em all. Its simple, no radials, no lossy coax. Dipoles seem to like the "balance" of parallel earth below and are quieter, by nature.

In summary, that's my two cents. As far as non-directional antenna's go, the dipole fed with open wire line thru a tuner is the best all around performer. To get better performance you need a beam, IMO. 73

Rob N8BEG
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Chris, Great idea for the antenna theory 'discussion net'.

What about say 10:00 AM California time on 40 Meters, say, 7228 and up?

73! de John
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Oh sorry, I was thinking about the weekend -- Saturday?

You guys might want to slip the time a bit too, I was just trying to keep things earlier, before the skip gets long!
 
A Vertical Antenna Advantage  
by N0AH on May 19, 2005 Mail this to a friend!
Verticle? Ok, time to move on......................
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 19, 2005 Mail this to a friend!
Rob, I don’t know if you have some anathema repugnance to book learning but, even if you do, that is Ok with me -- I like learning from real experience and conceptual models!

Ground Planes are quite different however from a 2nd quarter wave “image element” in the ground. That can be one way to do it but, there is a scientific term that describes the physics -- it’s called p!ss poor!

Think in terms of VHF! You would never even want to run a VHF signal through your TransMatch, you would lose 20 or more dB’s of signal!

Engineer an antenna for:

1) Minimal loss

2) Best possible gain

Apply that to HF!
 
RE: A Vertical Antenna Advantage  
by N0TONE on May 19, 2005 Mail this to a friend!
Rob, I'll n8"beg" to differ with you (pun intended).

I've had the luxury of owning enough land to have the antennas under comparison so far apart that the coupling was negligible.

For a simple antenna, a vertical with any reasonably-considered ground plane is superior to a single-element horizontal antenna at any easily-achieved height. That is, for true DX. If you want to work stateside, 'tis true, the dipole at a quarter to a half wave above ground is hard to beat.

On the receive side, the vertical's transmit advantage (low take-off angle) becomes a deficit - its lobe is right there on the ground, happily collecting all the noise from city sources within 5-10 miles of you. Even a Yagi sitting atop a 100 foot tower doesn't cover the zero degree angle as well as a vertical. Therefore, I often use a dipole as an RX antenna, and a vertical as a TX antenna.

I've sometimes set up two beacons on the same band - one with a vert antenna, and one with horizontal, and then asked folks for sig reports. The vertical generally wins by about one S-unit on TX, although you'd never think that on receive.

By the way, good textbooks do a very good job of indicating the expected effects of real world ground, and do a good job of explaining what to do about it - and how to take advantage of it. You may need a different text book!

Feedline losses are another issue. If you're having trouble with them, then you simply haven't thought the problem through. You can use any feedline with any antenna. When I've had verticals a long distance from the TX, and I'm at high enough frequency to care, I've used open wire feeders, with a balun on each end. Baluns are pretty easy to fabricate with less than 0.1dB loss to VHF. If you don't like coax, don't use it, no matter what the antenna.

AM
 
RE: A Vertical Antenna Advantage  
by W8JI on May 20, 2005 Mail this to a friend!
RE: A Vertical Antenna Advantage Reply
by K7PEH on May 19, 2005 I am not sure I followed your calculations or what you are saying. And, I have degrees in Physics with advanced degrees in Math. I know, there is still magic with ham radio, right?>>

I think Vito is **trying** to use some beamwidth he picked to calculate gain (but I'm not positive).

It doesn't work that way, because the arbitrary value of beamwidth has to be based on more than what we "want" it to be.

Not only that, applied power is lost as heat as well as other useless things such as minor lobes.

73 Tom
 
RE: A Vertical Antenna Advantage  
by AA4LR on May 20, 2005 Mail this to a friend!
"Modern research now reveals that verticals in the air at fairly modest heights with 3-6 radials can provide performance that is very respectable when compared to near ideal ground radial systems. This looks like its worth exploring. Verticals want to work and do!"

Did you READ W8JI's posting? This is a myth. The research shows that you need EIGHT radials elevated 1/4 wave in the air to come close to a ground-mounted system.

Elevated radials are a good alternative if you can't put down a bunch of ground-mounted radials, but they shouldn't be the first choice.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
K7PEH

Let both you and I look at a sphere. In a sphere there are 41253 computed square degrees area in the surface of a sphere.

Let us now try and take the gain of a 3 element yagi.

The lobe that is leaving the antenna looks something like a Zeppelin, cigar or a bullet. The forward point is the maximum power. Lets assume it will be 100 watts. We now look for a section of this lobe that is at the half power, 50 watts which we will call the 3db point and this point will be the amount of degrees. We do this both vertically and horizontally for the half power points which is 3db down. We now call these points "E" plane for the vertical plane and the "H" plane for the horizontal plane.

The "E" plane is 30 degrees. The horizontal plane "H" is 60 degrees. Now that we have found two points of this "beam width", we can now calculate the gain of this 3 element yagi in "isotropic gain".

30*60 = 1800

41253/1800 = 22.9

Log 10 of 22.9 = 1.36dBi

Multiply by 10 = 13.60dBd gain above an isotropic.

I said gain above an isotropic

We now can take other antennas and find the half power points and compare the gain between each.

Let us say that I just calculated a 0.625 wl antenna (5/8 wl) and the calculated gain was 8.84dB above isotropic.

The difference in gain between both will be 4.76dB but in different main lobe directions, the lobe of the 5/8 wl vertical is lower than that from the yagi.

Gain is meaningful only when considered with reference to a particular communications path and set of propagation conditions.

W6TH
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.


---------------W8JI Tom----------------------


--------------Read My Lips-----------------

W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by K5DVW on May 20, 2005 Mail this to a friend!
On the elevated radial myth subject...

The point in elevating the radial system is to reduce ground loss, which it does. If the radials are elevated high enough, ground losses are greatly reduced, especially over the same number of radials on the ground. That's not a myth.

W8JI wrote 3 dB of "pattern distortion". I'll buy that. Maybe Tom can clarify, is that efficiency loss or deviation from perfect omni pattern? At what height was the measurement taken? Pattern distortion from omni we can live with, loss we want to reduce. Yes?

How many radials at what height vs ground mounted is another complex and fascinating topic. "Low band DXing" has a good chapter on it. NEC4 has trouble with simulating it. Measured data rules.

My personal thought is that; yes, two elevated radials wont fly for a professional broadcast station, or someone looking for that last dB, but for a ham station, it's a reasonable way to do it and it may be better than a ground mounted vert with a so-so radial field. The bonus is if you elevate the antenna, you get it away from ground level shadowing objects and maybe local RFI too. That could be worth a couple of practical dB right there! That's not a myth either.

Anyway, interesting thread we have here. Vito, I still don't follow your math and I'm starting to wonder if you're comparing H to V planes or something. Tnx fer nice topic OM.

 
RE: A Vertical Antenna Advantage  
by K1DA on May 20, 2005 Mail this to a friend!
Beware those who tell you how many degrees they have, especally of the "Piled Higher and Deeper" type.
The guys who make the two way radios work for the
local police and fire departments generally have a
better handle on what works ('cause it has to) then
Mr. Theory personified who can give you 100 and 1 reasons why something else is better and your stuff is junk. K. I. S. S. applies when the radio has to work.
Lots of 1/4 wave veticals on police, fire, and public works vehicles.
 
RE: A Vertical Antenna Advantage  
by AB5XZ on May 20, 2005 Mail this to a friend!
I agree with W5DVW:

"A ground mounted vertical over even good conductivity earth isnt going to have any gain over a dipole at 1/2 wavelength above ground, and in the best case it's gain will be equal to a dipole in free space. Most likely, the gain is going to be less than 2 dBi (around 0 dBd) for a typical vertical installation. With no or few ground radials gain can be significantly less."

It appears that W6TH is applying liberal amounts of "pixie dust" to his numbers.
 
RE: A Vertical Antenna Advantage  
by WB2WIK on May 20, 2005 Mail this to a friend!
>RE: A Vertical Antenna Advantage Reply
by WA6BFH on May 19, 2005 Mail this to a friend!

Steve, I believe you are right. Sorry about the spelling. I first met him in 1969 when he gave a presentation at the ARRL Southwestern Division Convention. His talk was presented on his findings of the time, pursuant to the use of ‘low noise’ amplifiers for VHF/UHF. J-FET’s were becoming common then. The military was aware of GAsFET’s, nobody else was then thinking of NMOS or HEMPFET’s yet.<

I've known Louis almost my whole life. He is now retired and living in Baja California or Panama and has U.S. and Panamanian tickets, and is still active on HF anyway. He's not a scientist, though. He owned Lunar Electronics way back when and had a shop turning out VHF SS amplifiers for a few years.

Low-noise preamps or front ends are more helpful at VHF-UHF than at HF because it is true that sun noise diminishes with increasing frequency; however, the "low noise" aspects of solar, galactic and other atmospheric noises at VHF-UHF is enjoyed mostly at night, in the absence of lightning storms, and when antennas aren't aimed at noisy objects like the sun. Although noise diminishes with increasing frequency, available antenna gain increases with increasing frequency as well, and pointing that gain at noise sources easily overrides background noise even if you have a relatively poor receiver -- provided you have sufficient antenna gain.

I've never had such little antenna gain on six meters (using even a simple 6-7 element yagi) that I can't hear sun noise, if I aim at the sun.

I think six meters is a band on the cusp of low-noise advantage; my old nuvistor front end converters (~3 db n.f.) can "hear" every single signal my modern ARR GaAsFET converters (~0.5 db n.f.) can on six meters, as long as what I'm receiving is an off-the-air signal, via an antenna. In a closed system (signal generator, screen room), the .5 dB n.f. receiver is more sensitive; with an antenna connected, it's not.

There's never a time that my noise level doesn't increase when I connect an antenna on six meters; but it increases notably if I'm aimed at the sun, and this becomes a lot worse with big antennas. When I ran four stacked 5L 18' boom yagis on six for many years back in N.J. (and I brought the whole H-frame out to CA to use at N6CA/6 at Mt. Pinos, when we had our last operation up there), I could peak the sun 6-10 dB, easily.

WB2WIK/6


 
A Vertical Antenna Advantage  
by N6TZ on May 20, 2005 Mail this to a friend!
Verticals are great transmitting antennas. I shunt feed my tower on 30, 40, 60, 75/80, and 160 with very outstanding results. You can see it at this site:
http://earthsignals.com/N6TZ
On the other hand, verticals are lousy receive antennas especially in neighborhoods with high tech plasma screens, computer stuff, and etc. That is why I use a folded dipole for receive only while transmitting on the vertical. Some bands have a 20 db signal to noise improvement by using the dipole.
Hal, N6TZ
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.

K5DVW
If you can work with geometry or calculus, it would be a snap of the fingers. Today with computers and calculators it becomes childs play.

If you should work with the above mentioned, you may have a problem adding and subtracting, be on your toes.

Tom, W8JI, uses the EZNEC and tells me he does not use math for calculating, I say that is a bad habit like smoking and can cause sudden death.

73 W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
K1DA

Thanks for the compliment as I worked 2 way radio also, both General Electric and Motorola. Progress line through the solid state.

Progress line, motrac, master pro ring a bell?

Back in those days, men were men and women loved them that way.

W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 20, 2005 Mail this to a friend!
Yes, I did read W8JI's post and all the others here too. You might like to read the 3 part series in NCJ published this year about elevated radials over poor, average and excellent ground. The pattern distortion referenced has been revealed as being on the order of 1/4 to 1/2 db with as little as 2 elevated radials, hardly what I'd call consequential. 3-6 radials located a modest height above ground, placing the gain of the antenna within 1-2 db of what it would be over an ideal ground is my idea of a very cost effective and worthwhile to pursue solution to avoid 120 radials, etc.
 
RE: A Vertical Antenna Advantage  
by K5UJ on May 20, 2005 Mail this to a friend!
<<<So... my question. Do you or anyone here have experience with the MFJ 1792 80 - 40 meter vertical? It is 1/4 wave on 40 and top loaded using a capacity hat on 80. I plan to ground mount it in place of the GAP. I'll install as many radials as possible; estimating 8+ 66 footers for 80 and 16+ 33 footers for 40. Any opinions?>>>

If I were going to put up a vertical radiator for 80 and 40 meters I would get a 50 foot galvanized steel push up mast, strap each section to the one below it for conductivity, push it up on top of an insulator and guy it with dacron. I'd attach a 10 foot whip on the top for a vertical of 60' or roughly 1/4 w. on 80. I'd put a matching network at the base and run it as 1/4 w. or 1/2 w. on 40. Another possibility would be a 40' mast top loaded with a capacitance hat.
I have a feeling these would work better and be more rugged than the MFJ antenna. For some reason, the masts higher than 30' are getting harder to find. Nello in Nappanee IN took over the Rohn manufacturing but at last word (with me) had not started mast production. They supposedly plan to eventually begin making the Rohn series of push up masts. Getting the masts is the problem but of course aluminum could be used. It's just that if you go up very high Al gets harder to guy and keep up, especially with a hat and in a high wind location.

<<<As to radials, do you experts recommend insulated wire or bare copper? I intend to "staple" the radials to a close cut lawn and let the grass grow around them. This approach has worked well for me and avoids the effort of burying, slitting the turf or whatever.>>>

It doesn't matter. Normally insulated is paradoxically cheaper (more of it is made) so that seems to be what gets used. Don't use expensive hard drawn #14 bare 7 strand copper antenna wire at 4 times the cost of insulated #14 solid which you can get for $15/500 feet. The solid stuff is much easier to work with also. buy about 4 rolls for starters. plan on putting down way more than 8 radials.
 
RE: A Vertical Antenna Advantage  
by K5UJ on May 20, 2005 Mail this to a friend!
<<<3-6 radials located a modest height above ground, placing the gain of the antenna within 1-2 db of what it would be over an ideal ground is my idea of a very cost effective and worthwhile to pursue solution to avoid 120 radials, etc. >>>

How about some details? What band are we talking about here? What exactly is a "modest height?"

Everything has to be scaled to wavelength (remember, no free lunch). I bet on 160 m. that modest height blows up to being more than most hams (or maybe xyls) want to deal with.
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 20, 2005 Mail this to a friend!
AA4LR, years ago it was commonly believed that on the ground 120 radials 1/4 to 1/2 wave long were necessary to simulate the ideal. As an antenna was raised above ground level, it was believed that fewer radials were needed until at a height of 1/2 wave high, it only required 3-4. As more research is done in this area and the great body of experience expands, it becomes evident that closer to the ground may not require as many as formerly thought.
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 20, 2005 Mail this to a friend!
Since I'm recalling the articles from memory, don't hold me to exact figures. 40,80 and 160 meters were the bands analyzed. Heights of radials on 40 were something like 5,7.5,10, & 12.5. On 160 it was 15,30,45 & 60 ft. Interpolate on 80. I'd call radials of 5-25 ft. high or thereabouts to be modest. YMMV.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
WA6BFH

John, you are a 6 meter bug, I want you to give me some information as to the Cushcraft model AR6 Vertical.
Cushcraft claims a gain of 3dBi, with a radiation angle of 16 degrees "E" plane. The horizontal is 360 radiation degrees, "H" plane.

This would be 4.77dBd over the isotropic.

These are Ringo verticals at 1/2 wl.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.

John, sorry, I mean this would be 4.77db over the isotropic. Drop the d for now as we are going to show a strange gain figure.

.:
 
A Vertical Antenna Advantage  
by K8FLY on May 20, 2005 Mail this to a friend!
Bulk grounding worked well for me , i happen to have a scrap metal yard located not to far away , oh yes ha! the owner is one of my neighbors , anyway i aquired a lot of old window screen material , i took nuts & bolts screwed it all together & layed it out under my vertical section & covered it with soil . for the toehr vertical ( pair phased for 80 mtrs) i layed sheet tin under the leaves in the woods & covered them up with more leaves . this antenna has done well for me & has been in use for quite some time . my other antenna is a tower mounted caged vertical , mounted on a 65 foot tower, it has old metal school door mat under it for a radial system . i could not tell you the specifics of radiation angle or pattern , but it worked well for me . i really dont have a lot of room here i live on a lot with good neighbors & no wife keeping an eye on me ha! so i never really fooled with laying wires out , i just by passed it & went right for the bulk grounding .
all the best Bill k8fly
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
WA6BFH

Here it is John, see for yourself. Cushcraft using the amount of 17500 square degrees and not the proper amount of 41253 square degrees. Numbers don't lie. Here is the proof.

The AR6 Cushcraft Vertical

16*360 = 5760

17500 / 5760 = 3.038 dBi


The 1/2 wave dipole

70*360 = 25200

17500 / 25200 = 0.694 dBi "this is wrong, wrong"

Should be using the 41253 square degrees of a sphere.

70*360 = 25200

41253 / 25200 = 1.637 dBi

Log 10 1.637 = 0.214

10 * 0.214 = 2.14 dB over an isotropic. This is correct.

Question: Why did Cushcraft use 17500 square degrees for the AR6 vertical and not the proper honest amount of 41253 square degrees? Because it made the gain in favor of what most hams enjoy reading and seeing.

Not the honest gain in isotropic gain as I post, which really is just a comparison for gain measurements and nothing more.


W6TH
.:
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 20, 2005 Mail this to a friend!
Vito, all other considerations aside for the moment, you have pointed to the fact that amateur antennas may not be honestly rated. The gain claims for many of the antennas in the amateur market are dishonest. Only those amateurs that make it a point to teach themselves antenna theory will learn to recognize this. The others have little chance to make good choices unless they just happen to trust someone elses judgement. And who might that person be? Personally, I'm quite content to do my own learning and make my own judgements.

Ham personalities being what they are, these forums often tend to become platforms for egos rather than for learning and idea exposure. This one has proven to be no exception.
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 20, 2005 Mail this to a friend!
I have used those antennas Vito, both on 10 Meters (up at 5000 feet on our 29.6 MHz FM Remote Base Station) and on 6 Meters at other Ham's homes. They are freak'n awful, with a very lossy impedance matching systems -- even on 10 Meters!

Give me a good'ol copper "J" any day!
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
WA4DOU

Very true Roy, we now know who they are. Find them on many other posts as well, not only this one.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 20, 2005 Mail this to a friend!
WA4DOU, these forums may indeed in cases become forums of ego but, if you think about that, what is wrong with ego? Without ego we would not strive to learn and achieve!

Would you work hard at a job all day long, five days a week, to then GIVE you salary to someone else? We who appreciate this hobby, in all that it has meant through history, would like others to appreciate it as well. Look at some of the questions on the “Elmer Forum”; you will recognize the ones that I am thinking of, these want simple ‘quick fix’ answers. They don’t want to learn anything!

Yes, you may well see ego displayed here on this forum but, if it truly is BS (Bad Science), that too will be disclosed! Like an old engineer friend of mine would say, you can’t beat Ohms law! Well, you can’t beat physics either!
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
John sez,

Would you work hard at a job all day long, five days a week, to then GIVE you salary to someone else?
---------------------------------------------

We all do it John for the high class welfare in our government, senators, house of reps, congress, judges, on and on.

As far as ego, can be taken many ways and I go along with Roy as self praise stinks, self centered individuals, etc. Not meaning you John as many gain knowledge from you. Others just play ego, repeat and no new knowledge.

W6TH
.:
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 20, 2005 Mail this to a friend!
I’m still interested in doing actual tests!

I have another thread running that has drawn in a number of interesting comments!

I suggested a ‘real time’ net, and it seems that the rats have fled the ship?

As I have said before, what are ya gonna do?
 
RE: A Vertical Antenna Advantage  
by W6TH on May 20, 2005 Mail this to a friend!
.
John, we will just grin and bear it. I had two good ones cancelled and don't think I will comtinue to put any more on. Let the others do it as it starts to change to a different subject which is really funny though.

EHAM is great and much can be learned so we will keep watching for some good ones from your.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by AL2I on May 20, 2005 Mail this to a friend!
Vito: Thanks for the info and effort.
 
RE: A Vertical Antenna Advantage  
by VE7ALQ on May 21, 2005 Mail this to a friend!
Radiation Resistance Rr for a base loaded whip is givin by the ARRL at

Rr=273*(l*f*12)*(l*f*12)*1.e-8

Where Rr is Radiation resistance in ohms
l is Length of Vertical in Feet
f is frequency in mHz

For a center loaded whip, the approximate Radiation
Resistance becomes

Rr=670*(l*f*12)*(l*f*12)*1.e-8

Thus you can see that a center-loaded whip will have
greater efficiency than the base loaded whip, even if
you consider that the Rc (or loading Coil resistance)
is also doubled. The reason you gain with a center
loaded Vertical is that the ground resistance is the
same as for the base loaded whip. Total resistance is

Rtotal = Rr + Rc +Rg

where Rc is the loading Coil resistance
Rg is the ground loss resistance

People are invited to ftp://ftp.yehudi.ca/ham-radio/r.f
to download a (short) Linux Fortran77 program which
will calculate the Radiation resistance Rr for short
(less than 60 electrical degrees) base loaded whips.

I did some calculations for the Bencher/ButterNut hf6v
vertical which is 23 feet long and base loaded, on
frequencies 3.5,7.0,10.1 mHz, and for an 8 foot base
loaded mobile whip on 3.5,7,14 and 21 mHz. To visit

surf ftp://ftp.yehudi.ca/ham-radio/hf6v.efficiency.txt
 
RE: A Vertical Antenna Advantage  
by WA1RNE on May 21, 2005 Mail this to a friend!

>I’m still interested in doing actual tests!

>I have another thread running that has drawn in a number of interesting comments!

>I suggested a ‘real time’ net, and it seems that the rats have fled the ship?

John;

This rat is still on board. Then everyone can get a chance to discuss and cuss LIVE and put their money where their mouth is. Surely, everyone will get a better understanding of all the theories live instead of waiting 12-24 hours for the next thread.


Isn't that the purpose for doing this thing we do??


As I said before, my antenna situation is in limbo and rains are forecasted for the next week starting today, but I'll get something going.


Are you still looking at 7.228 and up???


73, Chris



 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 21, 2005 Mail this to a friend!
Yup, listening to 7228 KHz right now at 16:32 UTC, or 09:32 local California time!

Good to have you on board!
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 21, 2005 Mail this to a friend!
Well, I just chatted with a guy in Apache Junction Arizona but, he is not a E-Hammer!

Where are all you guru's and RF experts?
 
RE: A Vertical Antenna Advantage  
by KG6WLV on May 21, 2005 Mail this to a friend!
My understanding is that the FCC specifies certain minimum antenna efficiencies (in mv/meter at 1 km) for the various classes of AM stations. The variable factors are always the "electrical height" of the antenna in degrees, and the ground conductivity; 120 radials is pretty much standard. Some radial systems are counterpoises, some undergrounded.
 
RE: A Vertical Antenna Advantage  
by K1DA on May 21, 2005 Mail this to a friend!
We have a former AT&T IMTS Motrac working as a 2 meter repeater. It must have put in 30 years in IMTS and we have about 10 more on it. Just goes and goes. Next stop for it was going to be a dumpster before we heard about it. One tube output and clean unlike a lot of the solid state amps. In the works is a two tube Micor repeater.

BTW with regard to folks who understand VHF verticals, I have known Dick Austin since he started Austin Antenna in a one room shop in Providence. He talks, I listen. Went to collage with W3LPL. I listen to him too.
 
RE: A Vertical Antenna Advantage  
by WA2JJH on May 21, 2005 Mail this to a friend!
K5UJ does bring up a point with elevated radials.
<<USING 3 OR4 RADIALS PER BAND>>>

Pythagorian theorem is my limit.The old right triangle.

Indeed on the lower bands, on must have plenty of elevation.

The hypotenous of the right triangle is each radial.
Many will find that the longer radials are not practical.

1)The end of the radial is to close to ground level.
2)The horizontal space needed for a low band radial
may end up on some persona non grata's property.


The point about center loading is well taken too.
Perhaps I should try center and end loading radials that are to long for a typical city roof.

This is a good thread. However battle of ego's, I get enough of that crap at the university!!!
 
RE: A Vertical Antenna Advantage  
by WA4DOU on May 21, 2005 Mail this to a friend!
K5UJ, well of course the elevated radials for 160 will turn out to be more than most hams want to deal with. But you have to remember that most hams don't want to deal with 160 meter antennas at all, in any form. Thats why most hams are not on 160.
 
RE: A Vertical Antenna Advantage  
by WA2JJH on May 21, 2005 Mail this to a friend!
160M elevated radials are absurd, I do agree. I know of plenty 160M ops that load up fences, rain gutters,
I am sure one could load up the Brooklyn Bridge on 160M.

Getting real, many hams do not have the space or 4
20M elevated radials. I only have roof rights for 2 20M
radials. I do have 4 10M radials. I use a 32 foot counter poise to provide a better than nothing system for 40m and 80M.

I am considered lucky by NYC standards. Some resort to a long wire out the window!

My first vertical as a high gain/avante M20 "window whip" It had a bracket that one could use wood screws to hold the 9 foot vertical. Of course the manual did not even mention the fact that a 9 foot wire counterpoise would improve performance greatly.

I added a 7 foot wire that was the longest length I could use, so not to dangle the counterpoise in front of the apt below.

I am toying with the idea of using center or end
loading for 40M and 80M radials. Should I bother to try?
 
RE: A Vertical Antenna Advantage  
by WA6BFH on May 21, 2005 Mail this to a friend!
Well Chris, this seemed somewhat useless!

Maybe you and I should try 17 Meters (18.128 MHz) at about the same time, or 7.228 MHz a bit later in the day?

73! de John
 
RE: A Vertical Antenna Advantage  
by W6TH on May 21, 2005 Mail this to a friend!
.

Hearing many sigs from Massachusets at 9:00 pm Saturday, May 21 John and worked 2 stations from Maryland at 9:10 with good sigs. I should be able to work Chris with just my Zepp at 23 feet.

As you know, my big arrays are down for moving. Band sounds greeeat, my first SSB contact in over 2 years.

Give me time, frequency and will look for you John.

73 W6TH.
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 22, 2005 Mail this to a friend!
.

WA6BFH John,

My server Earthlink will cut me off at midnight as they have some work to do. I am shutting down my electric here tonight as I want to disconnect all my 220 volt ac boxes.

I will return in 4 or 5 days to get a sked with you on 40.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by K5UJ on May 23, 2005 Mail this to a friend!
<<<K5UJ, well of course the elevated radials for 160 will turn out to be more than most hams want to deal with. But you have to remember that most hams don't want to deal with 160 meter antennas at all, in any form. Thats why most hams are not on 160. >>>

I think 160 has this image of being a band only accessable to hams with vast tracts of land so a lot of hams on city lots give up without trying. And I'm not about to pitch some mini-antenna that is 5% efficient. I put up an inverted L on my 50 x 100 foot lot and put down (to date) 91 radials on the ground. Yes, a number of them are only about 10 feet long, and while i have an antenna that's okay for ragchewing, it isn't a dx antenna, but that's why God invented 15 meters. But, it's still a full sized antenna, no coils, linear loading, or other tricks, and I kind of feel like if I can get on 160 from my postage stamp of property, a lot of other hams can too. Anyone who can go up around 50 feet can probably fit one of these on an even smaller lot than mine. The secret is to gently bend the horizontal part--it doesn't have to be straight, and there can even be a drop in the end of a few feet if necessary. Then, blanket the ground with copper, hi.
 
RE: A Vertical Antenna Advantage  
by WA6CDE on May 23, 2005 Mail this to a friend!
Ok... so you married a vertical... and now what....

I sure have to go back and take that new math course again... could be useful during tax time... ahhhh 2 + 2 - 1 = 10... great...

Can we get back to reality here... and leave alice and the cat behind...
 
RE: A Vertical Antenna Advantage  
by WA1RNE on May 23, 2005 Mail this to a friend!

"The secret is to gently bend the horizontal part--it doesn't have to be straight, and there can even be a drop in the end of a few feet if necessary."

>Then, blanket the ground with copper, hi."

Herein lies the problem, for me and I'm sure for many others. Copper doesn't mate up well with kids, lawnmowers and the wife. Can't say I blame her, as I wouldn't want her People magazines plastered all over my family room floor. I work too hard on the landscaping to start burying radials so that's out the window.

So to be reasonable, it means putting the antenna up in the clear, pretty much ruling out a vertical for 160-75 meters - at least for me, anyway.

WA1RNE

 
RE: A Vertical Antenna Advantage  
by WA1RNE on May 23, 2005 Mail this to a friend!

John, WA6BFH;
Vito, W6TH

Sorry, I've been unable to get anything going lately.

It's been raining around here to beat the band. I've worked in lousy weather but this QTH is very limited for antenna supports so I have to wait. I also ran out of wire and a few other odds and ends and need to go to HRO for supplies. A lot of the antennas I stored were not in as good a shape as I thought.

Hopefully I'll be able to get something going in the next week.

I have a somewhat unique idea for an HF multiband antenna which will hopefully be in use when we hook up.

Vito, glad to hear your back on the air....

73, Chris
 
RE: A Vertical Antenna Advantage  
by K4MPE on May 25, 2005 Mail this to a friend!
This article started off being of interest. Enjoyed reading many of the posts (pro & con). But it soon got out of hand becoming so far off subject (6 meter DX worked; using S meter/agc; etc) that I finally stopped reading the follow-ups. That kind of stuff should be in "chat rooms" and not posts that waste ones time in trying to filter out the junk from the subject matter.
 
RE: A Vertical Antenna Advantage  
by VE6CB on May 25, 2005 Mail this to a friend!
I agree, I also found the subject of interest. I was particularly intrigued by W6TH's math, which most people just ridiculed, and obviously did not think too much about what was being said. The fact is there is nothing wrong with his math; at least as a first approximation.

The mathematical procedure does, however, produce erroneous results when applied to omni-directional antennas. I was also curious as to the source of assumptions made about the radiation patterns of ground mounted monopoles. Ground conductivity is also a significant factor in antenna performance.

Frank

 
RE: A Vertical Antenna Advantage  
by W5DXP on May 26, 2005 Mail this to a friend!
W6TH's 5.14 dBi gain for a 1/4WL vertical seems to assume zero ground losses. For average ground, the maximum gain is very close to 0 dBi. Thus says EZNEC using VERT1.EZ. 73, Cecil, W5DXP
 
RE: A Vertical Antenna Advantage  
by WA6CDE on May 26, 2005 Mail this to a friend!
Look... were talking verticals here...

The major advantage to one is the space requirement... well... if you go putting out radials around it uniform how much area do you take up.... could a moderate dipole be put up with much less effort and expense???...

Ihave use verticals for years... quick to put up... and tune... (4/5/6 BTVs)... but, now that I have been experimenting with antennas for some time I find that they are not all they are made out to be...

Angle of take off.... field of radiation... to ground or not to ground... radials or not...

The angle of take off.. is what... a couple of degrees... so the chart says.... ahhh but, what is it now that were looking at antennas the military is using... INVS... go streight up and back down.. for the best coverage... after all not all hams are going to be talking around the world every day... they like the nets and friends within a couple hundred miles... so why worry about take off angle...

Field or radiation... here we have the ground plane field... yep the other half of the antenna... is what your standing on... vs if you had a dipole... that was elevated above you... by some distance...

De-coupling of the vertical is also a problem... that will follow you right back into the shack... and rase its ugly head as RFI...

Grounding... or up in the air... really makes no differance... so we have found... yes you put it on the roof and it ends up with drooping radials... which change the impeadance some... and open up the irradiation field for more exposure... so you could say it will work better.. but, ground mounted with at least 4 radials on each band for a multi band vertical... is to say the least the min of what one should have... Just going out and pounding a pipe into the ground.. ain't going to do it... unless you have some real good soil around which conducts well... but, as we have said before... if you put a pipe in the ground... to mount it and then put the radials out.. you in effect have made it the best its going to be... radials will overtake the soil conductance... and I still need someone to prove to me that the far field is in effect when one puts out a set of radials... ie in space would a ground plane antenna have a far field... didn't think so... so what makes you think that if it does exists on earth... it would have a benifical effect on the vertical...

Ground radials are the other half of the vertical system.. you need them... as they become the other side of the tuning equasion... i.e they tune the vertical element just the same as you go out and adjust it... make them too short and the vertical element will go high in frequency... make them long and it will go lower in freq without changing the vertical part...
Yes the radials are part of the antenna system... not the soil that its over per sey...

How well do they preform compaired to other antennas... well from my expericance they are noiser, more prone to fade and or course require more labor to install correctly.... as to signal... the more area you can capture in space... the greater the coupling to have a effective ERP equivliant... but, as far as recieving... which is the other half of the transmission on our end... it seems that you can have a choice of either horz or vert polarization... and their sometimes the vert is better if not too noisy with QRN but,... most of the time... verts are not the antenna that one thinks they are... and no matter how you look at it... if you use a trapped multiband vert... your going to have losses which you wouldn't have if you used a 1/4 wave or half wave dipole... that being said with respect to the transmission line loss... as we all know that you can have the best antenna in the world and if your using a feed line that is garbage... doesn't gain you a single DB kinda thing...

For restricted space... they work... for a primary antenna I would go with a wire one over the vertical.

WA6CDE

 
RE: A Vertical Antenna Advantage  
by VE6CB on May 26, 2005 Mail this to a friend!
Yes 5.14 dB gain is correct for a quarter wave monopole over a perfectly conducting ground. I was trying to point out that there is nothing wrong with the math, only its aplication, particularly with regard to monoples.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by VE6CB on May 27, 2005 Mail this to a friend!
For those interested in a rigorous analysis of ground mounted verticals, I suggest reading the following: "Short Low- and Medium-Frequency Antenna Performance" by Trainotti et al from 54th IEEE BTS Symposium, Washington, DC, Oct. 2004. The paper was reprinted in the May/June, 2005 issue of QEX.
 
RE: A Vertical Antenna Advantage  
by W5DXP on May 27, 2005 Mail this to a friend!
For people who want close to real world results without the heavy math, a free demo version of EZNEC is available from www.eznec.com. When the guidelines are adhered to, EZNEC results are very close to reality. In particular, a ground mounted 1/4WL vertical is about 6 dB *down* from the maximum gain available with a 1/2WL horizontal dipole over that same ground. My vertical and dipole are compared at http://www.qsl.net/w5dxp/dipvsver.htm 73, Cecil, W5DXP
 
RE: A Vertical Antenna Advantage  
by K7VO on May 27, 2005 Mail this to a friend!
WA6CDE pretty much hit several nails squarely on the head. I do use a small 9' tall vertical (a Mini-Multi HT-3 for 10/15/20m) and it works well for my situation. I live in half of a very nice, very modern, 1860s duplex on a truly tiny city lot way up on a high hill. The house is built entirely in the height and in the length of the lot. The width is all of 13' and the steepness of the slope and small backyard below my deck makes a dipole almost impossible at a decent height above ground. The tallest tree in my backyard isn't as high at the top as the window in the room where my shack lives.

With the tiny space a vertical off the deck on one mast (with three radials), with a single trap and a capacity hat at the top works about as well as anything I can get away with without alarming the neighbors :) The other mast holds my three KU4AB loop antennas (6m/2m/70cm) and a small 222MHz beam. A random wire stretches from the LDG balun in the shack to the aforementioned tree. I also have a counterpoise for it running down from the window to ground level maybe 25' below.

None of this is ideal. All of it works well given the limitations of where I live. The height and panoramic (as in unblocked) view in three directions mean I do pretty darned well on VHF/UHF SSB/CW. On HF I make contacts, even at QRP power levels.

So... yes, a vertical works. It has advantages in terms of space. It's not directional so I hear everything equally well or poorly, whichever the case may be. I can compensate somewhat for the higher noise level with a good DSP. The vertical antenna advantage is for city dwellers like me. For folks with space to play with and no restrictions give me a beam or dipoles any day.

73,
Caity
K7VO/8
 
A Vertical Antenna Advantage  
by WB9YCJ on May 29, 2005 Mail this to a friend!
Love my Cushcraft R-7 so much I bought another one new in box for future use.
 
RE: A Vertical Antenna Advantage  
by W6TH on May 30, 2005 Mail this to a friend!
.
W5DXP says,

For people who want close to real world results without the heavy math, a free demo version of EZNEC is available from www.eznec.com. When the guidelines are adhered to, EZNEC results are very close to reality. In particular, a ground mounted 1/4WL vertical is about 6 dB *down* from the maximum gain available with a 1/2WL horizontal dipole over that same ground.
-------------------------------------------------------
Do you really believe this or do you mis-interpret the real meaning?

A dipole is rated at 2.14dB and a 1/4 wl vertical is rated at 5.54dB over a dipole.

.:
 
A Vertical Antenna Advantage  
by W0IVJ on May 30, 2005 Mail this to a friend!
W5DXP says,

For people who want close to real world results without the heavy math, a free demo version of EZNEC is available from www.eznec.com. When the guidelines are adhered to, EZNEC results are very close to reality. In particular, a ground mounted 1/4WL vertical is about 6 dB *down* from the maximum gain available with a 1/2WL horizontal dipole over that same ground.
-------------------------------------------------------
W6TH responds,

Do you really believe this or do you mis-interpret the real meaning?

A dipole is rated at 2.14dB and a 1/4 wl vertical is rated at 5.54dB over a dipole.

-------------------------------------------------------

Come on, Vito. Even by your reasoning this could not be true. The vertical is omnidirectional in azimuth, whereas the dipole has more gain broadside than off the ends. There has to be a price for the omnidrectional characteristics of the vertical. It could not possibly have 5.54 db gain over a dipole unless you are not using a maximum lobe comparison. The truth of the matter is that a vertical has 5.07 dbi gain at 0 degrees elevation angle at all azimuth angles when constructed with #12 wire over a perfect ground plane. The dipole has 7.82 dbi gain at an elevation angle of 33 degrees broadside to the dipole when constructed with #12 wire at 1/2 wavelength above a perfect ground plane. Since both are specified in db above isotropic, the dipole has 7.82 - 5.07 = 2.75 db gain greater than the vertical when you compare their MAXIMUM lobes under the above mentioned conditions. The only time the vertical exceeds the dipole in gain is at very low angles when the dipole is low and the vertical is mounted over extremely good ground. So much of antenna comparisons are apple and orange comparisons. That is why it is useful to use free space comparisons when talking about basic antenna types. When you have antennas over a real ground in the real world, then you can start comparing different gains at different azimuth and elevation angles, but you have to specify what lobes you are discussing.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by W6TH on May 30, 2005 Mail this to a friend!
.
W0IVJ
I did that tom.

You say:

When you have antennas over a real ground in the real world, then you can start comparing different gains at different azimuth and elevation angles, but you have to specify what lobes you are discussing.
----------------------------------------------------

A dipole at 70 degrees and 360 degrees = 2.14 above the isotropic.

A 1/4 wl vertical at 32 degrees and 360 degrees = 5.54 above the isotropic.

I am specifying the lobes for both Tom.


W6TH
.:
 
A Vertical Antenna Advantage  
by W0IVJ on May 30, 2005 Mail this to a friend!
W6TH,

A dipole at 70 degrees and 360 degrees = 2.14 above the isotropic.

A 1/4 wl vertical at 32 degrees and 360 degrees = 5.54 above the isotropic.

I am specifying the lobes for both Tom.

--------------------------------------------------------
Vito,

How high is the dipole, and over what ground is it? Is the vertical ground mounted or elevated? Or, are they both in free space? Are you comparing elevation angles?

A 1/2 wl dipole has 2.14 dbi gain in free space at 0 degrees elevation as compared to a 1/4 wl vertical having 1.77 dbi gain at 0 degrees in free space. That is with zero resistance wire which makes little difference in this comparison since the difference in length is only 1/4 wl. Also, doesn't it just make sense that the longer element would have more gain?

I know that you are of the old school, and I am not any spring chicken myself, but you are obviously of sharp mind and computer literate. Why don't you go to http://www.eznec.com and download the free version of EZNEC. Take the instruction tour. The free version is limited to 11 elements, but that is enough to do some of the basic antennas. Play around with it. I think you will find that it agrees with some of the things you already know, and it might clear up some things. It sure did for me.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by W6TH on May 30, 2005 Mail this to a friend!
.
Tom W0IVJ

You ask:

How high is the dipole, and over what ground is it? Is the vertical ground mounted or elevated? Or, are they both in free space? Are you comparing elevation angles?
-------------------------------------------------------

Tom, I am surprised that you ask these questions as they are very basic, been told over and over, especially for a Engineer dealing with antennas.
------------------------------------------------------

How high is the dipole, and over what ground is it? Is the vertical ground mounted or elevated? Or, are they both in free space? Are you comparing elevation angles?
------------------------------------------------------

Tom, same answer, even with Dr John Kraus (RIP), Terman, Brown, La Porte, Paul Lee and several others who have used math and not a software product. You are one heck of a good salesman, but have not convinced me, for my use. I will continue to use Geometry, Trigonometry, etc, for my fun thing as antennas..

Just my last note and that is a 1/2 wl dipole, a half wave above ground will not compete with a half wave vertical, ground mounted, especially on the forty meter band.

73, Vito W6th
.:
 
A Vertical Antenna Advantage  
by W0IVJ on May 30, 2005 Mail this to a friend!
Tom W0IVJ

You ask:

How high is the dipole, and over what ground is it? Is the vertical ground mounted or elevated? Or, are they both in free space? Are you comparing elevation angles?
-------------------------------------------------------

Tom, I am surprised that you ask these questions as they are very basic, been told over and over, especially for a Engineer dealing with antennas.
------------------------------------------------------

How high is the dipole, and over what ground is it? Is the vertical ground mounted or elevated? Or, are they both in free space? Are you comparing elevation angles?
------------------------------------------------------

Tom, same answer, even with Dr John Kraus (RIP), Terman, Brown, La Porte, Paul Lee and several others who have used math and not a software product. You are one heck of a good salesman, but have not convinced me, for my use. I will continue to use Geometry, Trigonometry, etc, for my fun thing as antennas..

Just my last note and that is a 1/2 wl dipole, a half wave above ground will not compete with a half wave vertical, ground mounted, especially on the forty meter band.

73, Vito W6th

====================================================

Vito,

You say that I should know these answers, but you don't give them to me. Why? BTW EZNEC uses the same math as the old masters. It is just used in very small intervals which are then integrated. Your masters would have done the same if they had the availability of a home computer.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by W6TH on May 31, 2005 Mail this to a friend!
.
Tom, I gave you the information you wanted. Here it is again:

Just my last note and that is a 1/2 wl dipole, a half wave above ground will not compete with a half wave vertical, ground mounted, especially on the forty meter band.

Can also substitute a 1/4 wl vertical and make the comparison.
.:
 
A Vertical Antenna Advantage  
by W0IVJ on May 31, 2005 Mail this to a friend!
W6TH,

Tom, I gave you the information you wanted. Here it is again:

Just my last note and that is a 1/2 wl dipole, a half wave above ground will not compete with a half wave vertical, ground mounted, especially on the forty meter band.

Can also substitute a 1/4 wl vertical and make the comparison.
---------------------------------------------------------
Vito,

I finally got your angle information!

For the dipole, you are using a free space configuration and the 70 degrees is the 1/2 power beamwidth in the azimuth and the 360 degrees indicates the field is uniform in elevation. You divide 41253/70*360 and get 1.64. 10*Log(1.64)=2.14 dbi.

For the vertical, you are using a 1/4 wl vertical over an infinite ground plane. The 32 degrees is the 1/2 power beamwidth in elevation, and the 360 degrees indicates the field is uniform in azimuth. You divide 41253/32*360 and get 3.58. 10*Log(3.58)=5.54 dbi.

However, inorder to make a fair comparison, you need to put both antennas into free space. When you move the 1/4 wl vertical into free space the gain becomes 1.77 dbi not 5.54 dbi.

When you ground mount a 1/4 wl vertical over a perfect ground the vertical beats a 1/2 wl dipole, up 1/2 wl above a perfect ground, at elevation angles below 13 degrees. But the dipole beats the vertical by 5 db at a 30 degree elevation angle.

When you change the ground type to good soil (conductivity = 30 mS/m, dielectric constant = 20), The dipole pattern changes less than 0.3 db. On the other hand the vertical, with 120, 1/2 wl radials, beats the dipole at elevation angles below 7 degrees, and the dipole beats the vertical at 30 degrees by 6.5 db.

When you ground mount a 1/2 wl vertical over a perfect ground the vertical beats a 1/2 wl dipole, up 1/2 wl above a perfect ground, at elevation angles below 15 degrees. But the dipole beats the vertical by 8.4 db at a 30 degree elevation angle.

On the other hand the vertical, mounted on good soil as above, with 120, 1/2 wl radials, has the dipole beat at elevation angles below 9 degrees, and the dipole beats the vertical at 30 degrees by 7.9 db. The vertical beats the dipole by 2.3 db at 5 degrees and 5.8 db at 1 degree.

In conclusion: Your comparisons of the vertical and dipole had the vertical over a perfect ground plane compared with a dipole in free space which isn't fair. The advantages of the vertical over very good soil over the dipole only appears at very low elevation angles. This has been an interesting post, Vito, and I am sure that it has caused a lot of people to think.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by W6TH on May 31, 2005 Mail this to a friend!
.

Tom, I am very happy to know that you have been using my type of mathematics and have come to the same answers that I have used for the original posting.

This last posting of yours is in agreement of what I have been posting and our gain measurements are exactly the same. I see no difference of the EZNEC calculations, but with one exception and that is I have the pleasure of knowing that EZNEC is nothing more than a clone of what many mathematicians have set forth for the none math folks.

For the sake of simplicity, then this is a draw, is it not? I will not mention that the EZNEC isn't so hot on the right angles, I enjoy ; right angles, horizontals and perpendiculars. Yes, I downloaded the free copy.

In other words, EZNEC has taught me nothing I did not know previously, but lets me know that I am from the old school and have done my own homework.

73, Vito W6TH

P.S. I saved some $149.00, makes me feel good.
.:
 
RE: A Vertical Antenna Advantage  
by VE6CB on May 31, 2005 Mail this to a friend!
Given that you know the beamwidth of a particular antenna I can easily see, using your math, how you can calculate the gain.

If you then consider an arbitrary antenna structure, whose performance is unknown. How, using simple math, do you calculate the radiation pattern and gain etc?

As an example consider a horizontal, rectangular loop, 0.1 Lambda high; with short sides 0.125 Lambda, and long sides 0.25 Lambda. The loop to be fed in the center of the short side. The structure to be located over a perfectly conducting ground. I have not yet solved the pattern for such an antenna.

Regards,

Frank
 
RE: A Vertical Antenna Advantage  
by W6TH on May 31, 2005 Mail this to a friend!
.
VE6CB

Frank, the EZNEC does have a problem with right angles. Could be the reason for a non solve problem. The EZNEC is not perfected to 100 percent accuracy.

I don't want to bad mouth the EZNEC and was only interested in applying my own system of mathematics that others may gain some knowledge along the way.

You can solve most problems with just Trig and Geometry without going into higher math.

I had a eye operation a few days ago and am touch typing, so hope I am not making many typing errors.
.:
 
RE: A Vertical Antenna Advantage  
by W6TH on May 31, 2005 Mail this to a friend!
.
VE6CB Frank,

The best way is to build a miniature model of your design. Then put it on a Polar recorder and take the vertical and horizontal 3db points called "E" and "H" planes. You will then have a chart recorded that you can take the gain and the 3db power point for the gain measurements. Then on the same Polar pattern, you run a dipole of the same frequency and power and compare one against the other.. No math or calculations needed.

.:
 
A Vertical Antenna Advantage  
by W0IVJ on May 31, 2005 Mail this to a friend!
VE6CB,


As an example consider a horizontal, rectangular loop, 0.1 Lambda high; with short sides 0.125 Lambda, and long sides 0.25 Lambda. The loop to be fed in the center of the short side. The structure to be located over a perfectly conducting ground. I have not yet solved the pattern for such an antenna.
-----------------------------------------------------------

Frank,

I modeled your loop with EZNEC. It has a maximum gain straight up(elevation angle = 90 degrees) of 8.22 dbi. At the high elevation angles, the pattern is omnidirectional in azimuth. As you move down in elevation angle the pattern favors the long direction. For example at 45 degrees elevation the gain in the long direction is 4.25 dbi and in the short direction it is 3.0 dbi. At 20 degrees the gain in the long direction is -2.87 dbi and in the short direction it is -6.79 degrees. As you can see, being that low it is a cloud warmer.

On the other hand if you move it up to 0.5 wl above the perfect ground 20 degree gain is 5.23 dbi and 1.34 dbi. At 45 degrees the gain is 5.37 dbi and 4.09 dbi. The maximum lobe is at 33 degrees with gains at 6.54 dbi and 4.62 dbi.

I hope this helps.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by VE6CB on May 31, 2005 Mail this to a friend!
Vito,

Thanks very much for your comments. Building a scale model is a thought. I have seen such scale ranges, and they can be very effective. The perfectly conducting ground does make the problem easier. I am not familiar with the simple trigonometric and geometric analysis you mentioned; though it does sound most interesting.

I have never used EZNEC, so am not familiar with its limitations. I, am however, quite familiar with NEC2 which has no limitations on wire bends of constant diameter wire. Junctions of dissimilar diameters (even axial junctions) do lead to significant errors.

I will attempt to model my proposed antenna, and would like to compare my results with others. I will also try a model over average ground of: permittivity 13, and conductivity 5 S/m. I suspect, since it is very close to the ground, that the radiation will be largely omni-directional, with poor low angle performance.

Best regards,

Frank
 
A Vertical Antenna Advantage  
by W0IVJ on May 31, 2005 Mail this to a friend!
Frank, VE6CB,

I forgot to say that at a height of 0.1 wl, the antenna feedpoint impedance is 18-j1060. If you are using this at uhf over a ground plane, it makes a pretty good antenna pointing away from the plane.

73 Tom W0IVJ
 
RE: A Vertical Antenna Advantage  
by VE6CB on May 31, 2005 Mail this to a friend!
Tom,

Thanks for your interesting analysis. I have not yet attempted such a model, but will be interested to compare my results with yours. I have no intention of actually building such an antenna. I was curious as to how to solve the appropriate field equations without software (or writing your own code). FEM and MOM methods are certainly non-trivial, and I do not feel up to it without a lot more effort. Simple trigonometric and geometric methods sound most appealing.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by W6TH on May 31, 2005 Mail this to a friend!
.
Frank,

Now that you have all the information, try and compare it with another type of antenna and check if it is worth having over a dipole.

Have Tom compare it to a dipole and will give you some idea of what you will be using.
.:
 
RE: A Vertical Antenna Advantage  
by WB5HZE on May 31, 2005 Mail this to a friend!
Tom, thanks for the clear analysis that everyone understood and could agree with. And Vito- thanks for the stimulating discussion . . . it forced me to return to Kraus & Terman for a review (and improved understanding) of some basic equations that were all but forgotten (I've been spoiled by the computer, I freely admit).

Frank, just for grins . . . if you rotate your model 90 degrees on the long axis, you'll get a nonresonant self contained vertical. If you rotate your model 90 degrees on the short axis (with the feedpoint) you'll get a nonresonant horizontally polarized, vertically oriented loop. Scaled up for resonance at the design frequency & placed at an appropriate height above ground, both of those antennas have good characteristics & happen to be a couple of my favorite wire antennas.

73 . . . Ron WB5HZE
 
RE: A Vertical Antenna Advantage  
by W6TH on June 1, 2005 Mail this to a friend!
.
Tom, I disagree:

For the dipole, you are using a free space configuration and the 70 degrees is the 1/2 power beamwidth in the azimuth and the 360 degrees indicates the field is uniform in elevation. You divide 41253/70*360 and get 1.64. 10*Log(1.64)=2.14 dbi.

Should read ( 1.64dbi)= 2.14db over an isotropic.
--------------------------------------------
Tom, I disagree:

For the vertical, you are using a 1/4 wl vertical over an infinite ground plane. The 32 degrees is the 1/2 power beamwidth in elevation, and the 360 degrees indicates the field is uniform in azimuth. You divide 41253/32*360 and get 3.58. 10*Log(3.58)=5.54 dbi.

Should read (3.58dbi)= 5.54db over an isotropic.
----------------------------------------------
Therefor I do not see the dipole being calculated as a free space calculation. Both have equivalent terms indicating the 1/2 wave dipole is above earth or ground level.
-----------------------------------------------
Tom, this is in conclusion, you mentioned:

In conclusion: Your comparisons of the vertical and dipole had the vertical over a perfect ground plane compared with a dipole in free space which isn't fair. The advantages of the vertical over very good soil over the dipole only appears at very low elevation angles. This has been an interesting post, Vito, and I am sure that it has caused a lot of people to think.
--------------------------------------------------
Your calculations above for the vertical and the dipole are correct and is fair. The antenna raised above earth for the dipole is a geometric function of the antenna height above ground. We both agreed that the information given was for a dipole at 1/2 wl above ground compared to either a 1/2 wl vertical or a 1/4 wl vertical at ground level.

A dipole at 2.14 dB above a isotropic.
A vertical at 5.54 dB above an isotropic

A vertical using a 1/4 wl vertical over an infinite ground plane.

A infinate ground plane calculated for both configurations.

Yes Tom I agree, I am sure that it has caused a lot of people to think.

73, W6TH.

.:
 
RE: A Vertical Antenna Advantage  
by W6TH on June 1, 2005 Mail this to a friend!
.W0IVJ

By the way Tom, take note of this from the higher math professionals:

The radiation from a ground based vertical is 3 dB above that from a free space dipole.

So be it.

.:
 
RE: A Vertical Antenna Advantage  
by WA6CDE on June 1, 2005 Mail this to a friend!
Ahhhhh.... your still compairing apples to oranges... I see...

when you say " For the vertical, you are using a 1/4 wl vertical over an infinite ground plane.

Then what is it when you use a infinite dipole....

Come on now... lets keep it withing the relm of reality... here guys... and gals... If you do it to one then you have to do it to the other... basic math eq... kinda thing...

But, I still have not seen anything or any proof that a infinite groud plane exisits... in free space or even on the earth... ground.

Once you have gone past the vertical radiators length in a ground plane... my notes show a lack of reflective contenuation of such... and in space what would it be... the e field... their is nothing their... so once it has passed the given ground plane... it appears as though it doesn't exists... so how can that be included in the equasion... No... no one still has actually proven a infinite ground plane exisits...in free space... for the vertical... similar the vertical while it has a lobe which is circular around the vertical irriadiating element to the ground plane... has voids where its not going to be as effective... any angle above 45 degrees by logic says that it approches 0... simialrly any angle below 45 also aproches 0... so where is the meat... the vertical then represents a null at both 0 points... where as the dipole... only has a much broader angle of energization... thus it has to have a better gain or efficency over all...for reactive RF energy huh... so while the 1/2 vertical only has a innertube or donut pattern in free space...in two physical planes only above the ground plane radial system... ONLY above the base raidal ground plane system ... that it can react with... Otherwise if you want to say it has a counter posed immage.... it would be... on ground... under ground... so half your power would be waisted... unless you wanted to talk to the worms...or keep them warm... but, we know that doesn't happen so basically we can conclude the immage is not their

the 1/2 dipole actually almost presents a spearical irradiation pattern... in all three planes

Agreed that when you sample within the donut your going to have more intense field and at a larger over all distance away from the driven element... but, you simply don't have the area coverage over all that the dipole would give in its sperical pattern... this being for the same given power...

So again we need to define our pramaters... as to just exactly where were going to sample our EMP and also the amount of field covered... You just can't take sections of the vertical pattern and say it has more... when in other areas it has 0.... while the dipole in free space or on the ground is consistant within its patten... again the vertical ground plane antenna in free space would not be the better of the two... nor is it the better on the ground either...

thats my take on it... WA6CDE
 
RE: A Vertical Antenna Advantage  
by WB5HZE on June 1, 2005 Mail this to a friend!
Tom stated the gain / directivity calculations correctly. They conform exactly with Kraus' examples in Chapters 2 & 3 of "Antennas," (Second Edition). I agree with his calculations & observations.

However- it is apparent that the equations themselves have not always been used appropriately in this & other discussions (considering cautionary comments read from Kraus & the dismissal of various K factors which would temper the results). I am also dumbfounded by the continual shifting of the discussion(s) to compare "apples with oranges"- I believe that most folks would agree that this is not good engineering practice. And lastly, Kraus tells us in Chapter 18 of "Antennas" that " while theory is essential to our understanding, experimental measurements determine the actual performance . . . " & then warms to the subject through that entire chapter.

There exists an abundance of good, hard experimental data to demonstrate how various antennas REALLY perform under varying REAL conditions. Mathematical approximations- or computer models, for that matter- are essential for the design process, but the rubber ONLY meets the road when a design is constructed and performance is measured. Consider the 5/8 wl vertical, a design whose calculated high performance (over a perfect ground) plummets when actually tested over soil.

But all the above aside, these discussions would probably be more enjoyable and productive if an effort was made to compare apples to apples. A comparison of one antenna over a ground to another in free space is meaningless. For that matter . . . a comparison of two antennas, both over unspecified ground, also lacks substance- the common ground type over which both are placed must be identified.

Ron
 
RE: A Vertical Antenna Advantage  
by WA6CDE on June 2, 2005 Mail this to a friend!
Sorry if this is just a short note....

but, this is the real approch to antennas...

D.Jefferies.... a noted antenna specialist wrote the following... for your consideration on this subject.

Most antenna calculations are made assuming that the time harmonic radiation has persisted/persists for all times past and future and so the problem of what happens at the start of a radiating wavefront is hidden from the analysis.

Further examination of the equations shows that A and therefore E (in the far field) lies in the preferred direction of the current sources. (The preferred direction may be taken to be an average direction over all the source currents.) The magnetic field B on the other hand forms loops around the current direction, and therefore B is at right angles to E and to the preferred direction of the current sources.
Moving charge constitutes a current. In most wires, there is a near-balance between mobile negative charge (electrons) and a background sea of positive charge (ions) which is stationary. It is therefore possible to have an "electrically neutral current" wherein the moving charge forming the current does not itself provide a source of charge density rho and therefore of electrostatic scalar potential phi. For this reason, in many antennas textbooks, near field as well as far field radiation is assumed to be entirely determined if only the current distribution in the source is known. This is sufficient for many antennas problems. However, where there are serious discrepancies between the predictions of standard theory and the measurements on a specific antenna structure, one should look to see if there are any significant time-varying charge accumulations within the antenna conductor structure, or on any local scattering objects. One should also look to see if there are any photons emitted by transitions between electron energy levels, and to see if there are any pre-existing EM waves.
Thus, If we know the current (and possibly charge) distributions on our antenna structure we should be able to calculate the fields anywhere for all time. However, in many antenna calculation scenarios the current distribution is not a "given" property of the problem. Often the antenna is connected to a length of transmission line (a feed), which may be coaxial cable, parallel wire line, microstrip, or it may be waveguide. The feed itself will have currents on it and may contribute to the radiation. Frequently one may assume a voltage at the junction between the feed and the antenna structure proper, but calculating the current and charge distribution on the structure after that point may be very difficult.
In aperture antenna radiation pattern calculations, a frequent ploy is to create a fictitious surface across the mouth of the aperture. Arguing backwards from the result, there will be electric and magnetic field lines intersecting this surface. One then can create an arrangement of fictitious charges and currents, and also magnetic charges and currents, on this surface. These are calculated to give rise to the local field structures on the surface, and then used to calculate the radiation field patterns at other points in space.

Of course, this method requires one to have a reasonably accurate knowledge of the fields on the fictitious surface in the first place, and this may be no easier than calculating the current and charge distributions on the source structure.

If the fields are known accurately across a surface one can use Fourier Transform techniques to calculate the radiation patterns in the far field. Such techniques are frequently referred to as the "geometrical theory of diffraction". If there are physical dielectric or magnetic obstacles in the near field then calculation of the perturbations of the field patterns by the objects may be necessary, such methods may be grouped under the heading "physical theory of diffraction".



One of the difficulties with all antenna calculations on complex structures is that in most cases the measurement techniques available do not have sufficient precision and accuracy to determine the validity of the calculation method used. Thus many antenna calculations have to be regarded as speculative; this is a problem for the simulator particularly if the method used consumes large amounts of computing resources to little avail.

I think he sums up what I and others have been saying all along... about the basics and the actual practical application of the vertical vs the horz... radiatiors...

i.e. the pramaters need to be specified and the subject be held to that level only... However, most Hams find the subject boreing and so... is only conserend with the final bottom line...

.. does this one work better than that one... for my application....

Thus, we can specualate all we want... and like cheifs with a pot of soup... each has their own taste... of how it should be made... grin...

WA6CDE
 
RE: A Vertical Antenna Advantage  
by WB5HZE on June 2, 2005 Mail this to a friend!
Considering the target audience of the article- clearly, folks new to HF who aren't already familiar with the common 1/4 wl vertical antenna- this entire discussion can be summed up in a few short sentences:

Everyone should have a vertical antenna- made to be as efficient as possible- because sometimes it will work better than a horizontal antenna. Everyone should have a horizontal antenna if they have the space- dipole, loop, yagi, quad, whatever- because often it will work better than a vertical. It's fine to calculate theoretical performance under perfect conditions, but it is preferable to consider actual performance under typical conditions that the average ham would encounter.

I wonder how many newcomers hung around long enough to understand that?

73 . . . Ron
 
RE: A Vertical Antenna Advantage  
by W6TH on June 2, 2005 Mail this to a friend!
.
WB5HZE

You will notice thqt Tom did not know the difference between dBi and dB. Also Tom did not consider that a ground mounted vertical is 3 db above the free space pattern as Kraus and many other math specialists mention.

The radiation from a ground based vertical is 3 dB above that from a free space pattern.

The proof is in the pudding that the EZNEC does work, providing the operator of such knows some very basic theory and can see some errors that occur, get involved.


EZNEC is great for those that have no knowledge of math and yet get the calculations needed for their project.

.:
 
A Vertical Antenna Advantage  
by W0IVJ on June 2, 2005 Mail this to a friend!
W6TH wrote:

Tom, I disagree:

For the dipole, you are using a free space configuration and the 70 degrees is the 1/2 power beamwidth in the azimuth and the 360 degrees indicates the field is uniform in elevation. You divide 41253/70*360 and get 1.64. 10*Log(1.64)=2.14 dbi.

Should read ( 1.64dbi)= 2.14db over an isotropic.
--------------------------------------------
W0IVJ responds,

No, Vito! dbi means db above isotropic. 1.64 is the ratio and has no dimensions. You don't get db until you take the Log. 10*Log(power ratio) and 20*Log(voltage or current ratio) are the correct calculations for db. dbi,dbm,dbw, etc are all calculated the same. The suffixes i, m, w stand for the references isotropic, milliwatt, watt respectively. There are new hams reading this stuff. We need to be accurate with our postings, otherwise we are spreading wrong information, and we both know there is enough of that.
==============================================
W6TH wrote:

Tom, I disagree:

For the vertical, you are using a 1/4 wl vertical over an infinite ground plane. The 32 degrees is the 1/2 power beamwidth in elevation, and the 360 degrees indicates the field is uniform in azimuth. You divide 41253/32*360 and get 3.58. 10*Log(3.58)=5.54 dbi.

Should read (3.58dbi)= 5.54db over an isotropic.
------------------------------------------------------
W0IVJ responds,

Same as previous response.
=======================================================
W6TH wrote,

Therefor I do not see the dipole being calculated as a free space calculation. Both have equivalent terms indicating the 1/2 wave dipole is above earth or ground level.
-----------------------------------------------
W0IVJ responds,

When you say the gain of a dipole is 2.14 dbi, then you , by definition, are talking about a dipole in free space. 2.14 dbi is the gain of a dipole in free space. End of discussion! If you place it horizontally or vertically over any kind of a ground, infinite, perfect, poor, or otherwise, its gain is not 2.14 dbi!!!
=================================================
W6TH wrote,

Tom, this is in conclusion, you mentioned:

In conclusion: Your comparisons of the vertical and dipole had the vertical over a perfect ground plane compared with a dipole in free space which isn't fair. The advantages of the vertical over very good soil over the dipole only appears at very low elevation angles. This has been an interesting post, Vito, and I am sure that it has caused a lot of people to think.
--------------------------------------------------
Your calculations above for the vertical and the dipole are correct and is fair. The antenna raised above earth for the dipole is a geometric function of the antenna height above ground. We both agreed that the information given was for a dipole at 1/2 wl above ground compared to either a 1/2 wl vertical or a 1/4 wl vertical at ground level.

A dipole at 2.14 dB above a isotropic.
A vertical at 5.54 dB above an isotropic

A vertical using a 1/4 wl vertical over an infinite ground plane.

A infinate ground plane calculated for both configurations.

Yes Tom I agree, I am sure that it has caused a lot of people to think.
-----------------------------------------------------
W0IVJ responds,

No Vito, we did NOT agree. From the start, you have compared the 1/2 wl dipole in free space with 2.14 dbi gain with the 1/4 wl vertical over perfect, infinite ground with 5.54 dbi gain. (BTW it is 5.15 not 5.54, but let's not quible about the small differences when we have a fundamental disagreement.) If you move the vertical into free space the gain is 1.77 dbi NOT 5.54. One of the advantages of doing free space calculations is the ground is not a factor in comparing basic radiators. We are comparing a 1/4 wl with a 1/2 wl radiator. In free space the orientation makes no difference. Once you place the radiators over a ground, then the height and orientation come into play. With vertical radiators, the type of ground is very important with respect to the gain, and it is the ground in the far field due to the psuedo-Brewster angle. The ground type makes little difference in the gain of horizontal radiators if they are higher that 1/2 wl above the ground. The height above the ground affects both in terms of their lobe pattern.

The only reason I am taking the time to do this post is to mitigate the false information that has been flowing freely. I want to thank WB5HZE for hanging in there for this long and for providing clarifying comments. This is all the time I am willing to spend on this. This exercise has given me a new appreciation for peer reviewed publications!

73,

Tom
 
RE: A Vertical Antenna Advantage  
by WB5HZE on June 2, 2005 Mail this to a friend!
Vito, I agree completely that NEC and MiniNEC based programs have value. And I concur that they all have limitations which must be understood.

But I ask- have you recognized that these are really productivity tools and not crutches? Far more can be accomplished in a shorter time frame with method-of-moments software than can by manual calculation, particularly when a design is complex. Personal time is scarce in today's world and we all try to make the most of it.

Therefore, it isn't fair to imply that use of modeling software indicates a lack of knowledge in base theory and the related mathematics. Granted, such software does serve to enable folks who don't happen to have a deep background in math & theory- and that's not a bad thing at all, it's a step forward along an interesting path.

On the other hand, it is probably true that "dependence" on modeling tools has led many away from familiarity with the core mathematics of the art. I wonder how many folks still remember how to use their slide rules, having relied on calculators for decades? Perhaps that is the point you have been trying to make in these discussions.

The math is indeed important & it is good to be reminded that we should not let it slide into oblivion.

73 . . . Ron
 
A Vertical Antenna Advantage  
by W7JI on June 3, 2005 Mail this to a friend!
10 DBD are you kidding! You will never see ANY gain over a dipole with a 1/4 wave vertical.
 
RE: A Vertical Antenna Advantage  
by W6TH on June 4, 2005 Mail this to a friend!
.
W7JI

You don't understand what is going on.

Figure this out as a extra class ticket:

10 x 360 = 3600

41253 divided by 3600 = 11.459

Log 11.459 = 1.059 times 10 = 10.59 dB over an isotropic.

Whether this is right or wrong to your ability to check, do you fully understand what this is about.

Back in the old days a extra class would understand what this is all about.

Due to the very low angle of radiation there may be much of the lobe absorbed by the lossy ground, but here is some fun math for you to check out.

.:
 
RE: A Vertical Antenna Advantage  
by W6TH on June 4, 2005 Mail this to a friend!
.
W7JI

You don't understand what is going on.

Figure this out as a extra class ticket:

10 x 360 = 3600

41253 divided by 3600 = 11.459

Log 11.459 = 1.059 times 10 = 10.59 dB over an isotropic.

Whether this is right or wrong to your ability to check, do you fully understand what this is about.

Back in the old days a extra class would understand what this is all about.

Due to the very low angle of radiation there may be much of the lobe absorbed by the lossy ground, but here is some fun math for you to check out.

.:
 
RE: A Vertical Antenna Advantage  
by VE6CB on June 4, 2005 Mail this to a friend!
Vito, Assume you are talking about a ground mounted 1/4 monopole on a perfectly conducting ground. Using Terman's "Radio Engineers Handbook", 1943 edition, page 792, equation 20; with the following assumptions:
I=1A, H/lambda = 0.25, theta = 0 deg, and d = 1m. The input impedance is assumed to be 37 ohms. The power input is therefor 37W (I realize this is in the near field, but I have simply scaled the far field computation for 1m). The field strength at 1 m = 60 V/m, or a power density of 9.55 W/(m^2). If I now take an isotropic source with 37 W input, the power density at 1 m = 37/(4*PI*1^2) W/(m^2) = 2.9 W/(m^2). Therefore 10*Log(9.55/2.9) = 5.18 dBi, in close agreement with my NEC2 program at 5.1 dBi. Assume everybody has access to Terman's text, if not I can attempt to reproduce eq. 20 here.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by W6TH on June 4, 2005 Mail this to a friend!
.
VE6CB

The last to W7JI was indicated to be a 5/8 wl vertical ground mounted and with the angles of a 5/8 wl from 3 to 27 degrees. I was then using the 10 degrees for calculating. 10.59 dB over an isotropic.

Either way with the "E" plane of 10 degrees and the 360 degrees "H" plane, our calculations should come out very close to one another.

73, W6TH
.:
 
RE: A Vertical Antenna Advantage  
by VE6CB on June 5, 2005 Mail this to a friend!
Ok Vito, thanks. now I know I understand what you guys are talking about.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by VE6CB on June 5, 2005 Mail this to a friend!
I have made a quick analysis of a 5/8 wavelength monopole over a perfectly conducting ground. Note there appears to be errors in Terman's equations 20 and 21 (p 792). In equation 20 the two COS terms in the numerator are reversed. In equation 21 the loop current for a 5/8 antenna is < 0. The magnitudes of the solutions do appear to be correct. These equations seem to be essentially the same as Kraus' (2nd edition) equation 1. page 473. Using Excel to solve the equations; the 5/8 wave vertical has a gain of 7.3 dB, and a 3dB beam width of 17 deg. NEC2 shows a gain of 7.9 dB and a 3 dB beamwidth of 18 deg.

According to NEC the radiation resistance of a 5/8 wavelength antenna is about 130 ohms.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by W6TH on June 5, 2005 Mail this to a friend!
.
VE6CB

Frank, now you can see how easy it is to compare one antenna towards another without the use of a NEC or EZNEC of any kind. All this amounts to is to calculate with just multiplication and division and the ratio of Log 10 P/P. No big deal.

A 1/4 wl vertical of 45 degrees "E" and the "H" 360 equals 5.8 dB over an isotropic and the 5/8 wl vertical with a "E" of 10 degrees and the "H" of 360 degrees equals 10.59 dB over an isotropic. Indicating the choice would be the 5/8 wl vertical. Not only the dB, but for the lower angle of radiation.

No need for any other information for the novice as the matching network will handle that.

This is in comparison to oranges to oranges and not as some other indicates oranges to apples. No need for a engineering degree and no reason for argument.

73 W6TH
.:
 
RE: A Vertical Antenna Advantage  
by VE6CB on June 5, 2005 Mail this to a friend!
I agree Vito, were are comparing oranges to oranges. Our analysis of quarter wave verticals, above a perfectly conducting ground, seems in fairly close agreement. Our results for a 5/8 wave vertical has a 3 dB difference.

73,

Frank
 
RE: A Vertical Antenna Advantage  
by K2BK on June 27, 2005 Mail this to a friend!
"I was under the impression that broadcast stations were REQUIRED by the FCC to have 120 ground radials. I didn't think it was optional and they couldnt use less if they wanted to? "

The 132 radial rule comes from work an FCC engineer did back in the early '30s (in the "High tech days ;).
And like most burocratic institutions, once stated, they left it a closed issue... that is until the early 90's.

Back in the early 90's, the FCC granted an STA to a AM broadcast station (around 990 kcs) in Schenectady, NY. It was granted because the antenna site was a working apple orchard, and the trees couldn't be dug up.
The STA was to use 6 radials that were 7 feet off the ground, and was conditional that the station met their license radation pattern, and energy flux at the required distance.

The antenna was a sucess, and the advantage was that the pattern and flux did NOT change with the seasons and/or rain and wetness of the ground.
Because of this station, STAs can be had by any AM station.

K2BK
 
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