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Antenna Myths

bob raynor (N4JTE) on July 6, 2011
View comments about this article!

ANTENNA MYTHS VS REALITY

Submitted by N4JTE.

Definitely gonna open up a can of worms here but after seeing so many ill-conceived ††antenna questions and articles on various internet sites, I wanted to revisit a few concepts that seem to be written in stone and have become internet folklore myths propagated, so to speak, on your first google search.

UPFRONT;

Antennas are extremely subjective, even the most advanced phased array or that 700 ft multiband loop you got up at 100 ft. can fool us into thinking itís the best idea since Marconi. If you are using a slinky in your attic then build a magnet wire, invisible dipole, strung out to an available tree itís gonna make your day.

Itís all relative to your experience.

I do not claim to be an expert, just coming from the knowledge gained from building at least 40 wire antennas from 160 to 2 meters over 30 years in multiple locations from stateside to Bahamas, Kuwait and many qthís in-between.

INVERTED VEE VS DIPOLE:

Sure, if you have a tight space and only one decent support it will do a credible job. HOWEVER, the whole low angle, better DX thing attributed to the inverted vee is hogwash ! UNLESS you can get the center up at least a 1/2WL and maintain a 90 degree angle at the feedpoint wires and keep the ends off the ground 1/4wl, you will be better off with a flat top dipole at half the height 90% of the time. There is one website out there that claims that you are better off with the ends at 2ft off the ground, amazing bad info!

VERTICALS ARE BETTER FOR DX;

Better than what? The hardest antenna to build in the ham world is an efficient vertical. To achieve the low angle take off is no easy undertaking.

Too much is beyond our control unless you live on an out island in the Caribbean.

Near field reflection, ground loss, and current path return can be maximized by an extensive radial field be it buried or raised. BUT; the far field reflection is gonna determine your reinforced take off angle and signal out there. Problem is most of the time that is beyond our control. Vertical polarization is a worthy goal, I achieved a 20 degree take off angle with 20db of front to back with phased ground mounted shrunken quads but still can only get 5dbi of gain due to low height and ground losses.

RANDOM LENGTH, MULTIBAND, LADDERLINE FED WIRES;

Yep it is a good way to get multiband capabilities with a single antenna, definitely better than coax, BUT, ladderline is far from lossless when used in extreme multiband mismatched conditions, see Tomís, W8JI, excellent findings on this subject on his website.

Do not assume you are getting your signal, ERP, effectively on all the bands your tuner might be happy with because of the prevailing myth that ladderline will somehow ignore a gigantic mismatch and perform lossless miracles. Does anyone really believe that a 450 ohm feedline facing a 20 ohm or 5000 ohm antenna is lossless?

NVIS ANTENNAS;

Somehow this military variation has become the antenna de jour for folks looking for instant reliable close in QSOís on 40 and 80 meters. Get over it, 90% of wire antennas are already low enough to qualify for this NVIS thing. I for one cannot think of any reason to put an 80 meter dipole at 12ft. to achieve a dependable 20 or 200 mile daily contact. If the propagation is working that day then that will be the paradigm of performance, be it at 10 ft or 40ft. Stick anything you can as high and flat as possible. If you are lucky enough to have supports at 1/2wl high on your band of choice, you might not be able to work your neighbor everyday but thatís why somebody invented skype.

DOUBLE BAZOOKA ANTENNAS;

Letís pop this bubble, so to speak. The wide bandwidth, amazingly efficient myth is everywhere on the internet. It is probably the most over rated extremely heavy monoband wire out there.

Studies have shown, VK1OD and others, what a piece of junk this thing really is. The bandwidth is expanded around 15 KHZ, and actually has loss attributed to that miniscule bandwidth stretch! Seems like a lot of work and extra weight for an antenna less efficient than a dipole at the same height.

HALF SQUARES, DELTA LOOPS, QUADS,

I am assuming most people understand that these designs are all variations of wire vertical antennas, some closed loops less dependant on ground conditions but in the case of the 1/2 square, it is nothing more than a two element vertical, low gain, broadside array in desperate need of an excellent ground plane at near and far field to do anything equal to or better than a dipole at the same height. Occasionally it just might outperform a dipole if you have optimum ground conditions and achieve the lower angle takeoff often written of as gospel for any ground conditions.

OCD ANTENNAS;

That big heavy 9 to 1 balun is there to provide a relatively close match on multiple bands by selective compromise placement on the radiator. Nothing wrong with that concept except a lot of wasted power up there, but still better than on the feedline or the tuner in the shack. Sometimes it is nice to have the feedline closer to the shack entry due to available supports. It would probably be my choice if conditions dictated the need and I had 3 strong supports to hold this heavy sucker up the air.

DIPOLES DIRECTIONAL?

Not really, forget worrying about the orientation unless you get the sucker up in the air around a 1/2wl. Most of the time they will work perfectly fine in all directions if the prop is on your side. The beauty of the good old monoband dipole is it is about 90% efficient when fed correctly and cut to correct length.

Would I put up a rotatable aluminum dipole on an 80 ft tower for 40 meters, absolutely! Thatís when it does the directional thing, more a signal to noise advantage in a non gain antenna but worth the investment at the right height.

PARASITIC VS PHASED ARRAYS;

A little esoteric but my experience on this dictates the sharing of my experience.

This probably is the first and last time I will ever disagree with the master, ON4UN.

IF you are after maximum gain AND front to back the only way to go, at least on thin wire antennas on the lower bands is to correctly phase them into a two element array.

Remember I mentioned antenna evaluation is based on relative experience?

My very first antenna article on Eham many moons ago was about a two element reversible 40 meter parasitic reversible quad. Wow was I impressed with myself until I built a smaller one phased and really saw the dramatic improvement, now Iím hooked on being the first one heard in DX pileups!

RESONANCE VS SWR;

I know this one has been beat to death but still annoying and frustrating when a manufacturer or article writer espouses a flat SWR as the paradigm of antenna performance. Of course beam antenna manufacturers are aware their antenna is not naturally resonant, thatís why there are mucho matching systems at the feedpoint.

SWR means nothing, nada, as far as antenna performance unless it suddenly rises while the wind blew your antenna down.

The only resonant antenna at 50/72 coax feedline ohms is a true 1/2wl dipole up at least 1/4wl. I will leave it to others to better explain what standing waves are, better yet read a few books! EVERY other antenna is gonna be above or below that 50 ohm coax at its feedpoint. How we choose to match this situation separates the signals from the noisemakers.

If you are building your own design, and I suggest you do, have a clue what the impedance should be at the feedpoint. A perfectly built vertical is around 38 ohm, dipole 50/70 ohms, a full size loop around 100 ohms, an EDZ around 5000ohms, 2 element beams around 27ohms.

None of these excellent antennas besides the dipole will have a 1 to 1 swr.

Before the day of 50 ohm transceivers the SWR issue was not the make or break thing it has become today with the modern radios.

Study the facts about standing waves and it will become clear to you that is but one aspect of antenna evaluation and in a lot of situations means a heck of a lot less than what you are actually trying to transmit a decent signal from.

FINAL THOUGHTS;

The true test of any antenna is CONSISTANCY and expectations thru many days, months, solar cycles etc. We all do the best we can and face multiple reasons for choosing what antennas we use. I only hope that some of my comments will help some newer hams take the time to study some real antenna theory, not the amazing amount of crummy ideas out there on internet antenna sites that promise impossible results.

Tnx for reading,

N4JTE

Member Comments:
This article has expired. No more comments may be added.
 
Antenna Myths  
by KC3JV on July 6, 2011 Mail this to a friend!
EDZ antenna. I don't remember seeing that one before? Enlighten me?
Mark KC3JV
 
RE: Antenna Myths  
by K5FH on July 6, 2011 Mail this to a friend!
"...an EDZ around 5000ohms..."

The ARRL Antenna Book says the impedance of an Extended Double Zepp is approximately 200-j900 ohms at its fundamental frequency. EZNEC confirms this. Relatively simple to match at the feedpoint for single-band use. Where did 5K come from?
 
RE: Antenna Myths  
by VK2FXXX on July 6, 2011 Mail this to a friend!
Perhaps he meant End Fed Zep?

Brendan
 
Antenna Myths  
by K1CJS on July 6, 2011 Mail this to a friend!
This is a subject that I'm on the bottom of the learning curve in, so, a question.

Recently, during Field Day, I had an opportunity to use an inverted V antenna which had unequal legs--I believe 42' 8" on one side to 21' 4" on the other. It was up about 15 feet with the ends about three feet off the ground. It seems that that antenna was doing very well--contacts all over the eastern part of the country. My home station is space challenged, so what is the opinion on that type antenna--raised up about 10 feet further at both ends and the center? I can just about fit that in my yard. Thanks!
 
RE: Antenna Myths  
by K1CJS on July 6, 2011 Mail this to a friend!
I forgot to mention that the bands used were 40 meters up. Matching was by an auto tuner.
 
RE: Antenna Myths  
by W5LZ on July 6, 2011 Mail this to a friend!
K1CJS,
That's an OCF antenna, the feed point if "off center". They work with a tuner (in most cases). From the sound of it, you don't have the room for center fed (or any other 'long' antennas) at home, and that's why I think you think it's a good antenna. The simple fact is that except for one band/frequency, the thing isn't resonant. Resonant antennas really do perform 'better'.

There are exceptions to everything! The author didn't mean for this article to be 'dead-nutz' definitive, it only shows that there are a lot of misconceptions/myths about particular antennas.
If a particular antenna 'style'/type works well for you, then use it. If you wanna try something else, do so, just don't forget how that other antenna was made/positioned so you can switch back to it if you want to.
- Paul
 
Antenna Myths  
by NY4FD on July 6, 2011 Mail this to a friend!
EDZ = Extended Double Zepp...
 
RE: Antenna Myths  
by K1CJS on July 6, 2011 Mail this to a friend!
Thanks, Paul. Now I remember the term--Off Center Fed. And thanks for the reminder about what works for one may not work for another. I often say the same thing! 73!
 
RE: Antenna Myths  
by WB4JZY on July 6, 2011 Mail this to a friend!
OCD ANTENNAS; "That's an OCF antenna, the feed point if "off center"....."

no, he meant an "obsessive compulsive disorder antenna"
 
Antenna Myths  
by KB2DHG on July 6, 2011 Mail this to a friend!
Nice article... We all would love to have that magical answer of what is the ideal antenna!
Unfortunately through my 25 years in this hobby I have in this hobby and all the antennas I have experamented with the one factor that has a great effect on any antenna is location.

When I lived in a house with lots of land and on top of a hill with a 360 degree clear view, I have a tower and 3 element beam for 10, 15 & 20 with several inverted V's for 17,80,40, & 30 meters. SWR and performance was never an issue!

I since moved to a restricted condo and had to surrender to a stealth G5RV dipole...

I came to this choice of antenna simply for the multi band capabilities it clames to have, and that I could only get permission to install one antenna and I like to work as many bands as I can. I am happy to say that I have it working fairly well but have to tune the heck out of it to get it to radiate and not really knowing the excat power I am actually radiating out from it. YES I have been working the world with it but having more of a challenge in doing so.

If you have the space and means go with a beam. If you can't then I reccomend multi dipoles cut for the specific band. If you are linited to one antenna and limited space the G5RV will get you decent contacts. BUT, again location and the proper instalation will have the main effect of the final outcome.

So to me and I am sure most will agree the antenna is the main element to top performance. If you had to invest in one thing in this hobby that will yeald the most results Invest in the best possable antenna system you can afford to buy. for the many like myself who have to deal with restrictions and regulations, My antenna of choice is the famed G5RV fed with 450ohm ladder line cut to 31 feet and bear copper stranded # 14 wire cut to 51 feet per leg equiling 102 feet across. MAKE IT YOUR SELF you can't buy a better G5RV antenna!
 
RE: Antenna Myths  
by KW4JX on July 6, 2011 Mail this to a friend!
How is a quad a 'variation of a wire vertical antenna' please?
 
RE: Antenna Myths  
by N3OX on July 6, 2011 Mail this to a friend!
"Antennas are extremely subjective"

Not if you make objective tests of how they work :D
 
RE: Antenna Myths  
by K3AN on July 6, 2011 Mail this to a friend!
Keys to antenna success.

1. Location. Hilltops are FAR better than flatland. I can attest to this from personal experience.

2. Height above ground. There's an old saying, "If your antenna didn't blow down in the last windstorm, it isn't high enough." Alternatively, local ground conductivity achieves importance if you're installing a vertical.

3. Gain

4. F/B
...
...
...

764. Resonance
 
Antenna Myths  
by K4AHO on July 6, 2011 Mail this to a friend!
An Antenna does not live in a vacumn. The effects of changing propagation overwhelm any performance differences of similar antennas. While antennas can be tested in the near field, it is the far field that makes the contacts...

The best way to learn about simple antennas is to operate QRP/P in the field. My experience seems to indicate a PAR 40/20& 10 EFZ portable special sloped at a 60 degree angle works best for stateside operation. BTW worked VK from FL with this antenna. Second best is a L shaped dipole fed at the lower corner. Vertical element sloped at 60 degree and horz element about 3' off the ground..

After 57 yrs of playing radio, I think antennas are still the last great mystery.

73

Jim
K4AHO
 
RE: Antenna Myths  
by K0BG on July 6, 2011 Mail this to a friend!
Gee Bob, you didn't mention anything about common mode. How come?

Alan, KōBG
www.k0bg.com
 
Antenna Myths  
by WV6U on July 6, 2011 Mail this to a friend!
I think big reason for such subjective range of opinions on antennas and persistence of myths is lack of objectivity in testing and reporting antenna performance. Most antenna reviews read something like "I threw a wire over a tree, loaded it up with a tuner and immediately started working DX". The conclusion being my antenna is great. Instead, it would be much more helpful to report some basic operating conditions when you tested the antenna - (1) Power (2) Solar data (flux,A/K index) (3) Feed-point measurements for reactance and other parameters.

Sure, it makes antenna performance reports a bit more difficult to put together but over time will help the hobby immensely. A good data set would go a long way towards scientific understanding of antennas instead of the black art that most consider it, today.
 
RE: Antenna Myths  
by N6AJR on July 6, 2011 Mail this to a friend!
I only have 2 words on my favorite antenna :)







FAN DIPOLE






for real my favorite antenna is the steppir. I have a 3 element 6-20 meter up at about 35 feet at the moment ( digging the hole for the 55 foot tower as we speak).



the steppir , in all of its variations, gives you a resonant antenna on any frequency in its band path.



Lets say you are in a contest and working 14.020 as a cw op, then you set the antenna for 14.000 or 14.050 and you are golden.



Then lets say you decide to work some phone in the contest. You are working at 14.270 so you run the any=tenna up there and are once again resinant.



Now lets go do some RTTY, so you set the antenna at 14.080 and work RTTY.



This ability can also be comouter controlled, so the antenna follows you around like a puppy. add that to an auto tune amp, and some packet spots and you are in "one click" contest heaven.




The draw back to the steppir is that the boom is a fixed lenght so your front to back suffers a tad on the higher freqs, like 6 and 10 meters, but most all antennas are way to close any ways so live with it.



There are probably as many antennas ideas as there are hams, so put up something and go play.



It still amazes me that I can take some electricity in my shack and tickle some electrons in a piece of alunimumumunummun here and have some electrons in a piece of alumimunumunum at your house and we call it radio. I think it is more like Magic :)




 
RE: Antenna Myths  
by W4VR on July 6, 2011 Mail this to a friend!
Finally, a non-controversial article on eham. Congrats for pointing out some of the myths that have plaqued the hobby for years and will continue into the next century. By the way, with regard to the EDZ, I use two dipoles in my system which gives the same radiation pattern and gain as a center-fed EDZ.
 
RE: Antenna Myths  
by AA4PB on July 6, 2011 Mail this to a friend!
My favorite is: "end-fed half wave antennas are voltage fed and therefore require no current flow".

Say what?? P = I * E and if I = 0 then no matter how big you make E, the power (P) into the antenna is still zero. Zero power in means zero signal radiated.
 
RE: Antenna Myths  
by N4JTE on July 6, 2011 Mail this to a friend!
G3LBS, call it a folded dipole if that is more accurate, but looks more like two 1/4wl verticals at 1/4wl spacing.
Regards,
Bob
 
Antenna Myths  
by W2RI on July 6, 2011 Mail this to a friend!
Verticals *are* better for DX - if you have no other antenna. And they can be be better than a dipole, or a yagi, depending on the height of the latter.

Some simple rules of antennas:

a) If you only have one antenna, it is the best antenna you have (!)

b) If you can erect an antenna with gain (usually directional) this will usually - but not always - increase your likelihood of making the QSO.

c) You can have an antenna with huge gain, but if it's not delivering the signal where it needs to get to then a "less-efficient" antenna may do the job infinitely better.

d) Take-off angle and lobes can be your friend. They can also be your enemy.

e) Some antennas are better suited to receiving than transmitting, if you have several alternatives available.

f) You can never have enough antennas.

g) Usually, but not always, the higher the better. It depends on the location of your target.

Finally, and most importantly,
h) Antennas do not increase your signal strength. They can merely direct and focus it - hopefully to the location you want, and away from the areas you are ignoring.
 
RE: Antenna Myths  
by KE7FD on July 6, 2011 Mail this to a friend!
I believe one of the biggest motivations to strive for the lowest SWR these days differs from what it was when I got into radio sometime back in the previous century. Although most hams probably have to think about it, most of us would probably agree that we own solid state transceivers whose output circuits get very unhappy (yes, that's a technical term for some) with high SWR. So, from that perspective, having a low SWR is not a bad thing to strive for.

Antenna performance is another thing altogether. A well designed dummy load presents an excellent match too but they make terrible antennas. (Although, I did work a station a few hundred miles away as a novice when using a Heath Cantenna at the other end of a 3-foot coax on 40 meters, but you didn't hear me say that.)

According to every article, antenna book, modeling software, and guru atop snowy peaks, an 80m full-size loop makes a terrible DX antenna as the pattern lends to their nickname of "Cloud Warmers". And I'm sure if I had a perfectly flat lot with ideal supports, landscaping and Venus aligns with Mars, the pattern would in fact burn a hole in the sky above my house. However, none of my own elements matches the assumptions made in articles, antenna books, modeling software, or guru atop snowy peaks. I routinely work DX stations much farther away than 200 miles or more, as in Merry old England, Germany and Havana with very respectable signal reports. And that's just getting on the air a couple of times a year (you didn't hear me say that either) from my house station.

Anyway, thanks for stirring the pot.

Glen KE7FD
 
RE: Antenna Myths  
by N4JTE on July 6, 2011 Mail this to a friend!
Besides the obligitory notice of some typo's on ohms etc. and nomenclature mistakes, I have not seen any actual dispute as to my conclusions presented in the article.
Regards,
Bob
 
Antenna Myths  
by N2OBM on July 6, 2011 Mail this to a friend!
Thank you for the thoughtful article.

To me, antennas are 'the' fun aspect of this hobby.

Kinda in this order:

1. Any antenna is better than no antenna. Get off your butt...get something up, get on the air.
2. The dipole...simple, beautiful, simple, balanced, simple, cheap(ish).
3. The higher the better.
4. Don't skimp on the hardware or cable strain system.

I have played with about every common military antenna in the inventory....

After awhile you realize the real magic of radio is in the radio...the ability to recover an ant fart worth of energy (modulation), riding an ant fart worth of energy (RF) and hearing a human voice in the speaker.

Take a trip without leaving the farm! ;)
 
RE: Antenna Myths  
by KB1GMX on July 6, 2011 Mail this to a friend!
Some of my best DX was done when I'd forgotten I'd left one end (or all) of the wire on the ground!

I'm inclined to agree to a point with most everything said.

1. Any antenna is better than none.

2. A resonant half wave antenna be it dipole or end fed
is hard to beat.

3. Beams are nice but hey, below 10M they get big.

4. Shortend antennas are always inefficient, they just fit spaces better. (see item 1).

5. Verticals are (usually) half an antenna, the ground is not always.(see item 1)

6. An inverted L is a useful antenna. It's both over
rated and underrated depending on needs, length and
ground. It's also compact. It can be "center fed"
or end fed. Don't sweat the vertical to horizontal
ratio, do what fits.

If one antenna doesn't work for you,try another.

All claims are usually suspect unless there is something to compare to like a dipole at typical height.

If you want a bigger signal put up more metal (wire).

If you can't put up more, put it higher if possible.


Allison
 
Antenna Myths  
by G0GQK on July 6, 2011 Mail this to a friend!
I read the first comment and the "fun" has started ! Somebody has never heard of an EDZ, its an Extended Double Zepp. That's being pedantic !

I had a smart arse tell me I was talking garbage when I said a dipole was about 90% efficient, he said it was 100%. I trawled through the internet and found a document by one of the early US university radio experts, can't remember his name, who wrote this in his findings about 1930.

You're right about the low dipoles, most hams in the UK have dipoles about 25-30 ft above ground so the signals on 40 and 80 go straight up and down again so they aren't directional.

As you mention its hard to get a low angle vertical but that's the least of our worries. I have a 40 metre quarter wave with two raised quarter wave radials, on the day we had good propagation it got me to South Island NZ. What we need is some decent propagation, then most people wouldn't be worrying about all these different shapes of wire, they would be DX'ing !

An old timer once said to me, apart from a few antenna's, like a Yagi, with wire antenna's there isn't a ha'porth of difference between the lot of 'em ! And he was right, there isn't, its all in the mind !

G0GQK
 
RE: Antenna Myths  
by K9MHZ on July 6, 2011 Mail this to a friend!
"CONSISTENCY"


I guess the tone of these antenna posts is interesting. It's as though people are looking for a fight. "That antenna is a loser!" "SWR is no big deal!" "What a junk antenna!" "Antenna tuners are junk science!"

I mean it's as though a lot of antenna "experts" can't wait to get something off of their chests and tell everyone how stupid they are.

Lighten up.....you've got good info that people can use. Just lose the attitude, will ya?

 
Antenna Myths  
by AE6RV on July 6, 2011 Mail this to a friend!
"Does anyone really believe that a 450 ohm feedline facing a 20 ohm or 5000 ohm antenna is lossless?"

No. But it's as near to lossless as you need to worry about unless you deliberately try to make the losses high. Fractions of a db simply don't matter. Yes, if you try to tune in a ladder fed 20M dipole on 80M or 160M you will have losses. But that's beside the point. Or are you suggesting that we shouldn't use ladder line because if try really hard it will have losses on the lower bands?

Put up a dipole that's cut for the lowest frequency you want to work. Feed that with a ladder line (that makes it a "doublet") and a tuner and you have probably the best multi-band antenna that can be had.
 
RE: Antenna Myths  
by G3RZP on July 6, 2011 Mail this to a friend!
What's the magic about resonance? A Hertzian dipole 0.05 wavelngth long (3.3feet on 20m) is only 0.05dB down on a half wave dipole - IF you can get the same power into it. The impedance is so horrific that you lose all the power in the matching network, but resonance per se is not pre-requisite. Neitherwise are rhombics resonant.....although they can well be described as having the 'least dB per acre'.

It is often thought that lowest SWR occurs at resonance. T'aint necessarily so! Resonance (which is not the answer the Extra exam asks for) is when the reactive component is zero at a particular frequency and not at all others. NOT when XL = XC. That's an approximation which falls down when Q is low.


The original off centre fed dipole was described in the RSGB Bulletin in the 1950's by Macintosh, VS1AA. It was an antenna N half waves long, fed a quarter wave at the lowest frequency from one end with 80 ohm twin feeder. A later version used 300 ohm twin, basically to get 15m in. See the 4th edition of the RSGB Radio Communications Handbook, 1968, p. 13.51. No heavy transformer up in the air to catch fire!

 
RE: Antenna Myths  
by WA8MEA on July 6, 2011 Mail this to a friend!
And this is why it's called:

Antenna THEORY....

Tongue in Cheekly,

Bill
 
RE: Antenna Myths  
by N4JTE on July 6, 2011 Mail this to a friend!
AE6RV, what I AM suggesting is that it is not hard to match a 450 feedline to the band of choice by finding a tap place for connecting a 50 coax that will be at same impedance, 1 to 1, by shorting remaining end. No mismatch, no tuner needed, and not hard to do with anything approaching a 1/4wl/3/4wl of ladderline. A little more work than 450 into a tuner on multibands and hoping for the best, but less loss AND, no tuner, just a few knife switches.
Regards,
Bob
 
RE: Antenna Myths  
by AE6RV on July 6, 2011 Mail this to a friend!
"A little more work than 450 into a tuner on multibands and hoping for the best, but less loss AND, no tuner, just a few knife switches."

You make it sound so hard, and yet I've been using a tuner since I got my first HF rig n 1972. Seriously, check into the center fed doublet antenna. For the price, it's hard to beat. And I'd sure like to see some links to something showing you can get lower loss through coax than through a ladder line. It doesn't happen in real life.
 
RE: Antenna Myths  
by N4JTE on July 6, 2011 Mail this to a friend!
A coax matched to the correct tap point on any open fed wire line will be less loss than the alternative.
You misread my previous comment.
 
RE: Antenna Myths  
by AE6RV on July 6, 2011 Mail this to a friend!
Yes, I misread your post. You are correct, but only for the amount of loss in the tuner as compared to the loss in the coax. Neither will be significant in most cases.
 
Antenna Myths  
by W9IQ on July 6, 2011 Mail this to a friend!
Thanks, Bob for the nice article.

One extra consideration of antenna systems that are fed by ladder line and require a tuner to achieve the conjugate match, is the loss in the tuner. This is often overlooked as part of the overall antenna system in the zeal to espouse the low losses of the ladder line.

To get some insight into the tuner losses, take a look at Kevin's, W9CF, loss calculator on his web site:

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

- Glenn DJ0IQ and W9IQ
 
RE: Antenna Myths  
by KA6WKE on July 6, 2011 Mail this to a friend!
In the extreme that would be antenna compulsive disorder obsessive. Have to have it all in alphabetical order!
 
RE: Antenna Myths  
by KG4YMC on July 6, 2011 Mail this to a friend!
obsessive compulsive disorder antenna? you don't use a tuner, just one prozac pill , in line a day? that is one antenna myth I am not familar with . kg4ymc
 
RE: Antenna Myths  
by KG4YMC on July 7, 2011 Mail this to a friend!
ideal antenna would be a M.P.M.B.A. , muti personality ,muti band antenna. Also if you get buffeting from your fan antenna , try a dyson bladeless antenna ? ok , good night , but good info folks , seriously . kg4ymc
 
RE: Antenna Myths  
by KW4JX on July 7, 2011 Mail this to a friend!
W9IQ Glenn I wouldn't be surprised if many are using non-true differential tuners when you make that remark?
You need a true differential tuner like a Kilowatt Johnson Matchbox to use with ladder line, preferably with about 300pf in series with the input link for extreme impedance range. My religion forbids all coax, baluns and traps. I once found a horde of wasps in the trap of a beam 80 ft high. The best bargain of all-time for radio hams is 100ft of 300 ohm feeder from RadioShack. Gil W2/G3LBS
 
RE: Antenna Myths  
by W9IQ on July 7, 2011 Mail this to a friend!
Hi Gil,

You make an insightful observation. The far majority of tuners today are not optimized for balanced lines. There is a nice bit of coverage on this topic in the June 2011 issue of QST, in the "The Doctor is In" column by W1ZR.

Joel does agree with your assertion that the Johnson has better efficiency that "modern" tuners but it does not have the range or full WARC band coverage without modification as you point out.

For those who have never seen schematics for balanced tuners, take a look at this issue of QST as well as the September 2004 issue of QST that is referenced in Gil's article.

- Glenn DJ0IQ and W9IQ
 
Antenna Myths  
by K8KAS on July 7, 2011 Mail this to a friend!
Hi Bob, nice job and boy will the nit pickers love this one. I always get a kick when the weakest signal on the band tell's someone all he know's about antennas... ask the BIG siganls about their antenna and you will learn something IMHO 73 CU Denny K8KAS
 
RE: Antenna Myths  
by N3HKN on July 7, 2011 Mail this to a friend!
"Hi Bob, nice job and boy will the nit pickers love this one. I always get a kick when the weakest signal on the band tell's someone all he know's about antennas... ask the BIG siganls about their antenna and you will learn something IMHO 73 CU Denny K8KAS "

This reveals the last dimension in antennas. Money. The 10% of the richest Hams probably have the consistently "big signals". You can always buy performance.
 
RE: Antenna Myths  
by K9MHZ on July 7, 2011 Mail this to a friend!
"You can always buy more performance"

I'll agree only if you're referring to having money to buy enough land to put up a large, full-sized antenna system without compromises. If you're referring to money for big equipment, then I'll disagree. Good antennas are everything. An IC-7800 into an Alpha 8410 into a coat hanger would be very expensive, but won't perform at all.

 
RE: Antenna Myths  
by W5LZ on July 7, 2011 Mail this to a friend!
The best antenna I have is the one I have right now. The best antenna I have ever had was the one two (or three) antennas ago.
And naturally, my next one will be even better.
It doesn't matter what anyone else thinks. Does anyone reallythink besides me?
The best advice (most common?) I can think of is to fix it till it stops working. Then back up one step, or maybe two.
What 'works' for me probably won't work for you. Why? How would I know?

I've got this boat for sale...
- Paul
 
RE: Antenna Myths  
by W2DI on July 7, 2011 Mail this to a friend!
Very interesting, Bob, and insightful. I was just about to string up a 66' dipole feeding it with 50 ft. of TV 300 ohm twinlead from my manual (with balun) tuner. This being a small variation of the $4 all band antenna article found elsewhere; hoping I could cover the 40 thru 10 meter bands with fairly good efficiency. That may not be the case.

In the spirit of amateur radio I agree that experimentation is a good thing and making contacts with the rain gutter is something to be proud of.

I, however, hoping not to sound like I'm making excuses, am what you would call a 'casual' operator and tend to favor the low profile, simplistic approach. Get on the radio, make a new friend in another part of the country or the world, chat for a while and that's really what the hobby is - for me.

Conversely, I also have a tendency to wish to be 'green' with my RF. It would bother me to run my radio at 100 watts output and radiate 40 into the luminiferous aether, though I'm sure I would make contacts. I would rather turn the radio back to about 80 watts, radiate 60 or so and make contacts.

So, according to this fine article, my operating style and peculiarities in mind, and the hope to have an antenna that operates on 40, 17 and maybe one more band, what would you (anyone) do? A parallel dipole? A trap dipole? Anything else?

Knowing there is no perfect solution or 'right' answer, all opinions, except that I'm ugly, are welcome. Thanks in advance. 73.
Joe -- w2di






 
Antenna Myths  
by WI4P on July 7, 2011 Mail this to a friend!
Thanks Bob for a well done article.

John, WI4P
 
RE: Antenna Myths  
by K8CXM on July 7, 2011 Mail this to a friend!
Ants fart????
 
RE: Antenna Myths  
by AE6RV on July 7, 2011 Mail this to a friend!
"I was just about to string up a 66' dipole feeding it with 50 ft. of TV 300 ohm twinlead from my manual (with balun) tuner. This being a small variation of the $4 all band antenna article found elsewhere; hoping I could cover the 40 thru 10 meter bands with fairly good efficiency. That may not be the case."

It would be truly sad if this article convinced someone not to even try to use a 66' center fed doublet with a tuner. Or did I mistake the ironic humor?
 
RE: Antenna Myths  
by K8CXM on July 7, 2011 Mail this to a friend!
I've always believed in the 20 meter rule: Horizontal is better from 20 meters on up and vertical is better 40 meters and down. 30 meters could go either way. Reason is most average home owners can get a 20 meter or higher frequency antenna up at least 1/2 wavelength, but 40 meters and down are not so easy in the average city lot. However, verticals for 40 and down can be made and they can be very effective. Naturally, a decent ground is certainly going to make that vertical work better.
Hey, if you have 70' trees far enough apart, go with that 40 meter dipole. But, don't think too many of us have 135' trees 140' apart. But, even I have 50' trees 40' apart, perfect for those two 20 meter dipoles.
Does direction make a difference? Sure does on those 2 antennas, sometimes as much as 5 S units. One is NE/SW and the other NW/SE.
Verticals here are wire and fed in a fan configuration at the base with a single coax feedline (the 80 meter wire is an inverted L). 32 radials at least 35' feet in length are buried around the base. It works VERY well on 80 and gives me decent performance on 40.
I also have had numerous wire antennas, some better than others, but a simple flat top dipole at least 1/2 wavelength up works as well as anything. Second to that is a high inverted V with the ends as near flat as possible.
Mention is made of the EDZ (extended double zepp). I've had several of these, and they do work. However, because of their bit of gain, their beamwidth is rather narrow. IMHO, a dipole is better. Not as much gain, true, but a much wider beamwidth.
As I like to tell my ham friends,"work with what you got". ANY antenna is better than NO antenna.
 
RE: Antenna Myths  
by KJ4AGA on July 7, 2011 Mail this to a friend!
Ok, but it all boils down to.....whats the best antenna for you. If I'm happy with a hygain vertical because I have no trees in the yard or way to hang a dipole....thats what I'm going to use. This article is nice in that it rates effeciency, but there are other factors as well. We can't all have 40m+ beams on 100ft towers so something has got to be done with getting on those bands if your looking for that sort of thing. I do prefer dipole because I have no problems with them, but if I ever move to a smaller lot.....you'd better believe I would look at verticals.
 
RE: Antenna Myths  
by N2EY on July 7, 2011 Mail this to a friend!
"The only resonant antenna at 50/72 coax feedline ohms is a true 1/2wl dipole up at least 1/4wl."

Not true. A 1/4 wave vertical with drooping radials can have a feedpoint Z of 50 ohms. A gamma-matched tower can have a feedpoint Z of 50 ohms. A ZS6BKW can have a feed point Z of 50 ohms. A trap dipole can have a feed point Z of 50 ohms. There are many other examples.

---

Amateur radio antennas are no more than 10% electrical engineering and no less than 90% mechanical engineering.

---

As for "lossless ladder line", no transmission line is truly lossless. But good open-wire line can have very low loss, even when operated at considerable (10 to 1) SWR.

The problem is that the term "ladder line" has different meanings to different hams. And so does "considerable SWR".

The Ancient Ones, and some folks today, use "ladder line" made with #14 or heavier wire, spaced several inches with ceramic spreaders every couple of feet. Such a line is heavy and can be a challenge to deal with, but its losses at HF are very low and if properly made will last a very long time.

There is also manufactured "ladder line", sometimes called "fretline" which is two #18 or #16 wires spaced 3/4 or 1 inch apart, with plastic spacers every few inches. Such a line is somewhat more convenient than the big stuff, but its losses are higher and it isn't very common any more.

The most common stuff referred to as "ladder line" today is actually "window line". It consists of heavy-duty Twin-Lead (two relatively small wires embedded in a ribbon of brown polyethylene) with rectangular holes punched in it. It's convenient to use but its losses are much higher.

The Ancient Ones did things like feeding a 132 foot dipole (up high and in the clear) in the center with 65 feet of 600 ohm open-wire line, matched with a parallel-connected balanced link-coupled transmatch in the shack. The resulting system is very low loss on 80/40/20/15/10, in part because the components are all low-loss and in part because the SWR never gets much past 10 to 1. (On all bands except 80 the feedpoint Z is no more than a few thousand ohms and is mostly resistive).

That's a very different thing from a short low dipole fed with window line and an unbalanced tuner/balun combination.

73 de Jim, N2EY
 
Antenna Myths  
by N4EV on July 7, 2011 Mail this to a friend!
What a hornets nest! HI HI

I have learned quite a bit about antennas from a friend, K6AJ, Al Henderson (SK), He owned Signature Antenna Systems in San Diego and made antennas for the Navy and Air Force. Al's theory was the impedance of free space is 377 ohms so the antenna has to transform what ever impedance to 377 ohms. Start with a vertical with an impedance of 30 ohms at the base and near infinity at the top, somewhere along the antenna you will find the magic 377 ohms. Al thought that the closer the feed point is to 377 ohms, the better the antenna will work.

I will agree with Bob in his article that too many myths are being propagated and believed. However, as has been stated in this thread, what you have up and is working, it's the best!

I have had to settle with a dipole in the attic and did manage to get away with a Hustler vertical in the back yard. Both work but not the best setup.

Clayton N4EV
 
RE: Antenna Myths  
by W9OY on July 7, 2011 Mail this to a friend!
Dopey article

73 W9OY
 
RE: Antenna Myths  
by W2DI on July 7, 2011 Mail this to a friend!
To Bob, AE6RV -

I appreciate the comment, Bob

I think I will try the 66ft, 300 ohm fed dipole, hoping the mismatch doesn't get too high to cause significant losses. The feedline run is rather short and staying on 40 thru 10 may not present an outrageous situation.

Anyway, I have the antenna built and might-as-well give it a try.

If not, I have an idea for a Slinky Top-loaded Rain Gutter Antenna...the STRGA curtain.

Very good discussion.

joe -- w2di
 
RE: Antenna Myths  
by AE6RV on July 7, 2011 Mail this to a friend!
Joe,
I doubt you'll notice any losses. If you have any issues with tuning it, prune or add a meter to the feedline. Sometimes the impedance at the tuner is too complex for it to match. The important thing is to not let an article prevent you from giving it a try.

My 128 ft long doublet is only 23 ft off the ground with the last 20 ft of one end sloping to 8 ft high. I've managed to work almost all of the 80M pileups to Europe and Africa that I've tried. I admit to not having heard any 80M Asian stations with it. I don't see that as a big handicap considering the space I have to work with. I do run 800 Watts and only call when I can actually hear the DX.

73s

Bob - AE6RV
 
RE: Antenna Myths  
by N4JTE on July 7, 2011 Mail this to a friend!
Talk about irony, when checking comments to this article the " Double Bazooka " banner add was waving in glory at top of page.
Gotta laugh to stay sane in this life !
Bob
 
RE: Antenna Myths  
by N4JTE on July 7, 2011 Mail this to a friend!
"The only resonant antenna at 50/72 coax feedline ohms is a true 1/2wl dipole up at least 1/4wl."

N2EY responds;
Not true. A 1/4 wave vertical with drooping radials can have a feedpoint Z of 50 ohms. A gamma-matched tower can have a feedpoint Z of 50 ohms. A ZS6BKW can have a feed point Z of 50 ohms. A trap dipole can have a feed point Z of 50 ohms. There are many other examples.

I should have said the only true NATURAL antenna, all the examples you mention use a way to get to 50 ohms.
1; ZS6BKW; uses a twinlead matching line as any version of a G5RV.
2; Elevated vertical with drooping radials, you got me there, hi.
3; Shunt fed tower, matching system.
4; Trap dipole, yeah okay but only due to the coils adding or subtracting inductance to match feedline.

Appreciate your comments very much and tnx for adding positivly to the discussion.
Regards,
Bob
 
RE: Antenna Myths  
by KG4YMC on July 7, 2011 Mail this to a friend!
he didn't mention the HUNTER DX CEILING FAN ANTENNA ? Ideal for indoor or balcony outside restricted area. Also ' cool for field day . got to work on keeping the loading coils from flying off. I"ll try to sell the idea to mfj.kg4ymc yes, I really do know what a fan antenna is . also, if hit the reverse switch will it change the radiation angle ?
 
RE: Antenna Myths  
by W8AAZ on July 7, 2011 Mail this to a friend!
If I had some acreage, I would surely put up a pretty ideal antenna, like most hams I am stuck with cut and try, and try to get by. I work stations with my 20' high dipole and LL feed. Gotta live with it. But I am sure that the magic miracle antenna is about to emerge from some lab soon. Sure. If your antenna is a dud, tear it down and go to the next experiment. My only regret is that Rat Shack does not stock that nice antenna wire anymore.
 
RE: Antenna Myths  
by AE6RV on July 7, 2011 Mail this to a friend!
"My only regret is that Rat Shack does not stock that nice antenna wire anymore."

I've had the same length of #14 THHN stranded house wiring up for about 6 years, now. After a year or two the clear outer covering rots off and it looks like it has the mange, but the colored insulation remains. I got mine from Home Depot. It's available at Lowes, Ace, Tru Value, etc etc etc.
 
Antenna Myths  
by W6AAJ on July 7, 2011 Mail this to a friend!
We talk about higher is better regarding antennas. I've always wondered is that height above the local terrain or height over sea level. On HF,say 14.300mhz, does someone with a dipole x feet in the air on top of Mount Palomar have any advantage chasing DX compared to the same antenna with the same local terrain in the valley a mile below?

 
Antenna Myths  
by OLLIEOXEN27 on July 7, 2011 Mail this to a friend!
Recommendation: Half wave end fed antennas one for each band of interest in either sloper or vertical configuration. The best wire antenna ever requiring only a cheap tuner at the feedpoint, a short counterpoise, and coax to the shack.

Avoid any and all multiband antennas - you'll become frustrated and want to qrt from the hobby.
 
Antenna Myths  
by K1DA on July 7, 2011 Mail this to a friend!
There is a fair amount of info on the internet regarding how to make an inverted "L" work well. I called a JA on 80 SSB a few months ago on what I thought was my full size 80 meter vertical, turned out I was using my "local coverage" "L" instead. It delivered enough signal to JA to work him.

Advantage: easy to install no heavy duty supports needed to hold up the wire. Disadvantage: not easy to multiband without a tuner. Hint: Aside from matching you need to add a small "floating" counterpoise as the latest articles describe. An extensive ground system is not necessary. A current choke on the feedline helps keep RF out of the shack.
 
RE: Antenna Myths  
by N4JTE on July 7, 2011 Mail this to a friend!
Appreciate all the pertinent comments that actually referred to the content of the article, point was to educate new hams not to believe what they read on advertisements and wrong answers on various forums and READ some books and learn the basics of antennas, not sure I accomplished my original intent but I tried.
Regards all,
N4JTE
 
Antenna Myths  
by N1BHH on July 7, 2011 Mail this to a friend!
Very informative if people actually read this. It will blow a lot of people's supposed super antennas to shreads as well as some people's egos. It's best for people not to just look at the antenna but also at the feed method, the length of the feeder at frequencies X, Y and Z, and to look at what you have available.

I use an OCD for the fact that my feed point is directly over my operating position about 45 feet up and the end supports are conveniently at the right places. I also like to operate multiple bands and don't want to have to put up a bunch of dipoles for each band and have to go outside to switch bands when I want. I wanted the wire to be as high and in the clear as possible. I wish I could go higher with this but I'm going to need a seasoned bow hunter to place it at about 75 feet in the tree, or maybe some monkey to climb it for me.
 
RE: Antenna Myths  
by AE6RV on July 7, 2011 Mail this to a friend!
"We talk about higher is better regarding antennas. I've always wondered is that height above the local terrain or height over sea level."

I believe that the height refers to "height above average terrain".

"On HF,say 14.300mhz, does someone with a dipole x feet in the air on top of Mount Palomar have any advantage chasing DX compared to the same antenna with the same local terrain in the valley a mile below?"

If you're in a steep valley, you've got problems: your antenna is going to be below the average terrain level. Even if you're just on the plain beside the mountain, if you're close enough to the mountain it becomes a barrier to signals in that direction.
 
Antenna Myths  
by AE7MJ on July 7, 2011 Mail this to a friend!
Mr.Bob,
Nice article once again sir. Being upfront and honest without causing a flame-up is great to see. Must agree with what you've come up with for your 40m working antenna, as I do hear you quite well in WA on a very regular basis. --no Bob, your not "5-9" all the time, but I do recieve your signal generally better than others with the same "conditions".

[Bob and I participate in OMISS Nets consisting of around 40-70 stations working in the span of 1-4 hours time. Good antenna checking opportunity].

Anyhow, you have something that works for you...and I'm confident you'll find another that performs even better. Just as we all (hopefully) should be doing. I do like the 'don't take advertising as gospel' kick in the pants also. If every Johnny-Joe believed what was advertised we'd all be on dummy loads. What fun is that?
Over just one short year, I've listened literally to your ups and downs in the antenna saga. Don't stop now Bob....and keep the articles coming please.


Catch ya on the 'Nets
AE7MJ
(gotta update my E-Ham login still)
 
RE: Antenna Myths  
by G3RZP on July 8, 2011 Mail this to a friend!
I go with Jim, N2EY on open wire line. After trying several variations, I bought a load of ex USN ceramic insulators - I believe they were for WW2 aircraft wire antennas - at Dayton for $1 each. About 2-1/2 inches long, they are ideal spreaders for open wire feeder using 14AWG and have the advantage that unlike all the other ones I've tried, they haven't given up with UV. As the feeder goes to the dipole centre which is at the top of the tower, weight isn't important. A good old fahioned parallel tuned circuit, link coupled, gives a balanced tuner. Well, at least the thermoammeters in each leg seem to think so....A 60 foot or so feeder gives high impedance on both 80 and 40.

Vertical or horizontal? Yes. I have the 80m dipole fed with open wire line as a fullwave dipole on 40, basically horizontal. I also have a set of 40m sloping dipoles, with the unused ones tuned as reflectors, switch selectable. On a number of occasions on long path to VK in a morning on 40 CW, I receive better on the sloper for that direction, but get a 2 S point better report on the full wave dipole.

For 160, I frequently find the noise on receive using the dipole is lower than on the folded unipole vertical that is the tower. So the SNR on a DX station is better. That's how I worked Heard Island on 160...reasonable DX from the UK!
 
Antenna Myths  
by K7AZN on July 8, 2011 Mail this to a friend!
Dear fellow HAMS, What ever radiates a RF signal is a workable antenna, from bed springs to light bulbs,to a straight piece of wire. 150 watt bulb works OK.

 
RE: Antenna Myths  
by KK2DOG on July 8, 2011 Mail this to a friend!
When I point my Hustler vertical at Europe,
I swear it works better! ;)
 
RE: Antenna Myths  
by W5ESE on July 8, 2011 Mail this to a friend!
> I think I will try the 66ft, 300 ohm fed dipole,
> hoping the mismatch doesn't get too high to cause
> significant losses. The feedline run is rather
> short and staying on 40 thru 10 may not present
> an outrageous situation.

I predict this will work very well for you.

I used something very like it in the Texas QSO
Party last year.

73
Scott W5ESE
 
Antenna Myths  
by N0AH on July 8, 2011 Mail this to a friend!
How did you calculate the 20 degree take off angle on your vertical?
 
RE: Antenna Myths  
by KG4YMC on July 8, 2011 Mail this to a friend!
you were concern about opeing a can of worms on the antenna's you didn't mention the SOPCHOPPY FLA WORM GRUNTING STUB ANTENNA? A REAL GROUND WARMER. KG4YMC
 
RE: Antenna Myths  
by W9OY on July 8, 2011 Mail this to a friend!
If your point was to educate you failed

Verticals for example are not hard to make efficient, and at least on the low bands are good DX antennas.

The point of an open-wire fed antenna is its multi-band character with relatively good efficiency, not its incredible efficiency on every frequency. It is the first antenna I erect whenever I move to a new QTH because of its versatility.

Each antenna has its good points and its bad points, which often compete with each other and it all depends on which characteristic or what mix of characteristics are most important.

A better article would be to list each antenna type and its good points and bad points from an electrical and mechanical and perhaps cost standpoint. That article would actually inform the new comer in a way to help him make a decision. The hustler on the back of the car is a really good 80M antenna if the alternative is a paperclip but a really bad antenna if the alternative is a dipole at 150ft.

73 W9OY
 
RE: Antenna Myths  
by N4JTE on July 8, 2011 Mail this to a friend!
W9OY, been there did that, check previous articles under my call or better yet, write one of your own!
Bob
 
RE: Antenna Myths  
by W4VR on July 8, 2011 Mail this to a friend!
W9OY said: "A better article would be to list each antenna type and its good points and bad points from an electrical and mechanical and perhaps cost standpoint. That article would actually inform the new comer in a way to help him make a decision."

Good point! Why don't you do a NEC and structural analysis on every antenna in Bob's article and give the amateur radio community a report on the results...let's say no later than February 2012...36 years after his demise. If W2OY were still amongst the living he would think very highly of you for making this small contribution to Amateur Radio.
 
Antenna Myths  
by OLLIEOXEN27 on July 8, 2011 Mail this to a friend!
The commie obama destroyed NASA as part of his plan to destroy America.

The commie obama continues to destroy America by keeping interest rates at 2%. Nobody and no institution is going to loan money (invest) if they are only getting back 2%.

Still want to talk about antennas?
 
RE: Antenna Myths  
by OLLIEOXEN27 on July 8, 2011 Mail this to a friend!
Just having this guy in power makes people afraid of waking up everyday let alone invest their hard earned month in a system that can collapse at any time.

The bama can make as many speeches as he wants about how he loves America and loves the traditions of our space program but he is lying. He and the foreign interests that put him in power are methodically intent on destroying us from within. When our economy collapses (when we default), bama will create a communist state while claiming it's a new beginning.

Bama has the media in his pocket so while this is all happening the media will report we are going through a tough spell but things will get better...Let's watch Dancing with the Stars....

Still want to talk about antennas?
 
RE: Antenna Myths  
by OLLIEOXEN27 on July 8, 2011 Mail this to a friend!
oops - hard earned money...
 
RE: Antenna Myths  
by OLLIEOXEN27 on July 8, 2011 Mail this to a friend!
RE: The US goes into default, the government loses it's credit rating so the interest it has to pay skyrockets, entitlement funding stops, protests break out (like Greece), bama blames the Republicans encouraging the 'Have Nots' to blame the 'Haves', class warfare erupts, bama declares martial law and suspends the constitution.

That is the plan.

Still want to talk about antennas?

 
RE: Antenna Myths  
by KG4YMC on July 8, 2011 Mail this to a friend!
gee. the last guy will get flamed and not me for a change mabey, I guess we should invest in gold antennas , not onely be prepared for the economic fall but have best conductor material antenna made .kg4ymc is that were s.os. came from , socialist obama , stupid?
 
RE: Antenna Myths  
by KG4YMC on July 8, 2011 Mail this to a friend!
what is a differntial tuner? would that be posi track,? or limited slip tuner?
 
RE: Antenna Myths  
by N4JTE on July 8, 2011 Mail this to a friend!
Thank you Clinton, AB7RG, for making Eham articles a very interesting place and fun to read.
Do believe it's time for the next one, some trailor trash with no lives are infecting many good comments, sad, but internet is only place they have. It's like a dumb lid hearing things asking if freqency is in use.
Thats why 95% of my time is on radio and building antennas to talk to people that can spell a word.
Best to all,
N4JTE
 
RE: Antenna Myths  
by N5YPJ on July 9, 2011 Mail this to a friend!
It's very hard to define an antenna as effective in an approximate 24 hr operating period where a large percentage of hams are operating. Field Day is sort of like shooting fish in a barrel, depedning on your location operating skill & technique is the most important factor. As the author pointed out, the antenna that consistently performs day in day out, month after month, etc., etc. is the one to have. It does take experimenting to find out what will work for you.
 
RE: Antenna Myths  
by K1BXI on July 9, 2011 Mail this to a friend!
Nice article Bob, after reading all the posts I think you need to follow up with one titled:

"FEED LINE MYTHS VS REALITY"

John
 
RE: Antenna Myths  
by K0BG on July 9, 2011 Mail this to a friend!
Bob, I hope I didn't sound like I was trashing the article with my common mode comment, as that wasn't the intent. But I still think it should have been mentioned especially in the part about OCF doublets.

Alan, KōBG
www.k0bg.com
 
RE: Antenna Myths  
by K7JBQ on July 9, 2011 Mail this to a friend!
"FEED LINE MYTHS VS REALITY"

Hmmm, I think it's already been done, and then some.

Hint: Reflections, W2DU.

73,
Bill
 
RE: Antenna Myths  
by WA6MJE on July 9, 2011 Mail this to a friend!
I think the worries over ground loss in verticals is now mostly a myth. It is true that there are decades of articles that say this. However, more current information shows that a vertical with a few elevated radials really does quite well in terms of avoiding excessive ground loss and competes well with a vertical system that has dozens of buried radials. This was confirmed by simulation software in many newer articles, and in one extensive article I read by actual field measurement.

I read one article about why it is that articles and even text books on verticals have been so wrong about this for so long.

In any event, I live in an a HOA challenged QTH and have little option but a vertical. I studied the concept extensively, and learned that what I knew about verticals as a 50 year ham was wrong.

A few elevated radials do well. Yes there is some ground loss, but considering the performance of a low horizontal radiator, it is a good option. Spend the time to exploit efficiency, with good coax, large diameter radial wire, if you need a coil, make it high Q, and if you exploit these tricks, there is no reason to shy away from a vertical. Or, better yet, the reasons to shy away are probably mostly myth if you seek out and find the newer studies. Elevate the base about six to ten feet, and slope the radials down to no lower than two feet. It will perform well, and this can be easily studied with simulation software and confirmed by experience.
 
Antenna Myths  
by N6JSX on July 9, 2011 Mail this to a friend!
Interesting article with a lot of "hogwash", as you put it. I read some facts and many more opinions stated as facts - based on what is the real question?

Something I did not see in this article - what are your qualifications that gave you all this insight to all these antennas.

I know why eHAM posted the article as they are into hits, and most all HAMs are opinionated experts when it comes to antennas. Hell most HAMs think that getting a 1:1 VSWR makes a good antenna so using an antenna tuner will fix all antennas give maximum distance.
 
RE: Antenna Myths  
by N4JTE on July 9, 2011 Mail this to a friend!
Qualifications ? just as stated in preamble of article, and 30 years of building variations of every antenna mentioned in the article, anything mistated?
Always open to any peer review on what I write.
Regards,
Bob
 
RE: Antenna Myths  
by N4JTE on July 9, 2011 Mail this to a friend!
Or maybe, it's that that my latest antenna design is allowing me to talk to ZL's, SM7's, and G0's along with a bunch of stateside stations and have 5-9 qso's during a very big contest on this Sat night right on top of us, while using what amounts to a $50 antenna at 40 ft. high in a small backyard.
Bob
 
Antenna Myths  
by OK1RR on July 10, 2011 Mail this to a friend!
Excellent article with a lot of useful info! Indeed, there are more myths than facts about antennas. For sure, we need more such articles to put some light onto such "mysterious" subject. Many thanks, Bob!
 
RE: Antenna Myths  
by W1JKA on July 10, 2011 Mail this to a friend!
RE: Bob N4JTE
Or me with a 559 report from Tony W4FOA in Georgia this morning from San Diego,Ca. with 2 watts/MFJ Cub,battery power into a 20 meter end fed half wave(free zipcord)and a homebrew tuner made from 8 dollars worth of parts.To each his own HI.
Jim W1JKA/6
 
RE: Antenna Myths  
by N4JTE on July 10, 2011 Mail this to a friend!
Way to go Jim, nicely done!
Best regards,
Bob
 
Antenna Myths  
by WA6MOW on July 10, 2011 Mail this to a friend!
Thanks for a great article. Antennas are really fun to experiment with. Little antennas put out little signal no matter what the advertisers claim. When the band conditions are really good you can load a door knob on the higher hf bands and make contacts. Antennas work better as high as possible. Ground mounted vertical work better with a thousand radials. Magnet wire makes a great invisible antenna and can handle 100 watts. Fed at the end helps to hide the feed line. A new ham with a crummy antenna will lose interest in ham radio rather quickly.
 
RE: Antenna Myths  
by KA5SNG on July 10, 2011 Mail this to a friend!
Fine article BOB, I have 40/20 isotron up about 20 feet. On most days the antenna works fine, but the noise level is often high. I use an antenna match box. Thanks for your input on this much used and abused subject.
 
RE: Antenna Myths  
by W1JKA on July 11, 2011 Mail this to a friend!
I just finished reading Bob's informative article again this morning and gleaned some more useful nuggets of information from the comments column that I had some how missed in the advertising pages of the A.R.R.L. antenna handbook.
However I am puzzeled by OLLIEOXEN27's off topic comment about "bama".I know that "bama" is a HAM, but could anybody tell me if he holds an amateur radio license and if so is it real or fake.I could not find his name in the FCC data call sign base,but I attribute this to national security reasons.
As far as I know,the last american polit bureau member that would be interested in this antenna article would be Barry Goldwater(K7UGA)SK.Perhaps overly oxygenated OLLIEOXEN27 could confer with Donny Trump and enlighten me.Carpe diem .

Jim W1JKA
 
RE: Antenna Myths  
by KG6MZS on July 11, 2011 Mail this to a friend!
To add what Jim said about open wire antennas:

"Yep it is a good way to get multiband capabilities with a single antenna, definitely better than coax, BUT, ladderline is far from lossless when used in extreme multiband mismatched conditions... ...Does anyone really believe that a 450 ohm feedline facing a 20 ohm or 5000 ohm antenna is lossless?"

Yeah but those kind of mismatches can be dealt with simply by changing the length of the feedline. Admittedly any one-size-fits-all bands solution is a compromise, but doublet fed by good, true ladder line is a remarkably good solution

73 de Eric

 
RE: Antenna Myths  
by AE6RV on July 11, 2011 Mail this to a friend!
One issue no-one mentioned is related to old coax. If the end of the coax that's up at the antenna isn't hermetically sealed, moisture will eventually wick through a substantial length. This will result in large losses that may happen too slowly to notice: sort of like the proverbial boiled frog. If this happens, you will probably notice that the SWR doesn't change much (if at all) from one end of the band to the other and the band just seems "dead" all the time.
 
Antenna Myths  
by WD9N on July 11, 2011 Mail this to a friend!
I wonder if this guy has ever tried to maintain emergency communications over a period of time for a region?


The authors remarks on NVIS.

"Somehow this military variation has become the antenna de jour for folks looking for instant reliable close in QSOís on 40 and 80 meters. Get over it, 90% of wire antennas are already low enough to qualify for this NVIS thing. I for one cannot think of any reason to put an 80 meter dipole at 12ft. to achieve a dependable 20 or 200 mile daily contact."

How about requiring reliable communication in an area that has less than reliable power let alone internet connectivity or perhaps we like to communicate on radio instead of computer? If this is your case against the NVIS style of operating, we shouldn't be using radio at all. I can talk anywhere in the world on skype, so should we just let the FCC sell off all the amateur spectrum and end it all. Why put up a monster tower and phased array of beams when you could just dial them up on skype?

"The true test of any antenna is CONSISTANCY and expectations thru many days, months, solar cycles etc."

And that is why the military uses the NVIS style for regional communications, it is tested over many years and in many places and has had to work to keep people from dieing, that seems like a good consistency and expectation test to me.

You have contradicted yourself in one article, congratulations on convincing me to NOT read anymore of your articles.
 
RE: Antenna Myths  
by N4JTE on July 11, 2011 Mail this to a friend!
The military, for starters used a bent over vertical on the back of a truck 40 years ago in Thailand and found it helped on close in communications in mountainous regions. The wire ham versions are, as stated in my artical, not gonna do the same thing on the ground or any height above the ground consistanty.
I would be most grateful if you can provide any instance in the last 20 years where a ham on a "NVIS" antenna saved someone's life.
I have no problem as to your choice for no further reading of my articles, I will survive the loss by this time yesterday, but still can't find the contradiction you seem to be quoting. Sorry if you are that attached to the NVIS,
but reality trumps myths everytime, as will propagation or the absense thereof.
Bob
 
RE: Antenna Myths  
by K1BXI on July 12, 2011 Mail this to a friend!
Bob, I have to agree with you 100%....NVIS seems to be the new buzz word in antenna discussions.

It seems to me that all it does is to increase the ground loss to a point that all one can hear are the close in stronger signals and instead of more signal going straight up it gets attenuated in the ground, straight down.

John

 
RE: Antenna Myths  
by K1CJS on July 12, 2011 Mail this to a friend!
All W9DSC seems to be saying that the NVIS style of antenna seems to work for the military. If the military communications people can make it work, then why, as hams, can we not work with the same style antenna and even make them work better.

I concur with him that even though NVIS doesn't work as well as some other types of antennas, it DOES work.
 
RE: Antenna Myths  
by N4JTE on July 12, 2011 Mail this to a friend!
Okay as far as NVIS, if a ham wants to drive a humvee and tie/bend down a 14 ft vertical to his bumper than go for it, putting up low dipoles in a war zone with bombs falling on you is not what the military would consider an NVIS antenna.
Bob
 
Antenna Myths  
by N8CMQ on July 13, 2011 Mail this to a friend!
What I have found to be a big factor in making an antenna work, is, work...

I have a ground mounted 4btv/14avq modified per Sevick W2FMI back in 81.

While others may try that antenna, one thing they may not work on is the radial system that is half of the antenna.

I have 125, 30 to 35 foot radials (60 foot square), that I installed before installing the vertical. That is the work part of the antenna...

I thought I was going to work on WAS, but I have been busy working EC1KD, DL1MW, MD/DK1SG, YT9M, SN0HQ, VK7ZE, LR5H, WH7Z, XE2JA, ZX2B, PY2NY, IO4HQ, E7HQ, EF8HQ, and that was only two days working with 100 watts into the antenna, and that was against KW's with beams...

I get to talk stateside occasionally, though!
I did clean sweep the 13 Original Colonies contest, and got the bonus WM3PEN station as well, so I am happy with a ground mounted vertical!
 
RE: Antenna Myths  
by NN2X on July 14, 2011 Mail this to a friend!
I spent 3 months putting up two towers at 65 ft comparing Quads and Yagis, Compared Mono bander to Mono BAnd, and multiple band to Multiple band quads and YAgis for hf bands.. DId thins for lightning bolt.. Also compared QUad to quads, lightning bolt to CUbex...very expensive tests

At the end, MUlLTIBAND quad did very well against the multi band yagi, but mono band tests showed not much difference

The CUbex quad performed better due to separate feeds, the lightning bolt was much better mechincally a

Well, this was about 20 years ago, so I am sure things changed
 
Antenna Myths  
by W5DXP on July 16, 2011 Mail this to a friend!
> Does anyone really believe that a 450 ohm feedline facing a 20 ohm or 5000 ohm antenna is lossless?

Although 5000 ohms sounds like an unmanageably high impedance, e.g. a 130' dipole on 40m, a 450 ohm SWR of 5000/450 = 11.1 is acceptable to me and a lot of other hams. If we make the ladder line length equal to 3/4WL on 40m, the loss in the ladder line, according to VK1OD's loss calculator, is around 0.35 dB, about 0.06 of a standard S-unit, with 92% efficiency. The impedance looking into the ladder-line is 450/11.1 = 40.5 ohms for a 50 ohm SWR of 1.2:1 with no tuner required, i.e. *no tuner losses*. Of course, no transmission line is lossless but 450 ohm ladder line driving a 5000 ohm balanced antenna feedpoint impedance on 40m is close enough. :-)

http://www.w5dxp.com/notuner.htm
--
73, Cecil, w5dxp.com
 
Antenna Myths  
by W7KKK on July 16, 2011 Mail this to a friend!
And then there is that myth that some of us just have to be happy with whatever we can get away with in our current situation.
Such is the life of a ham!

73 de Ken
 
RE: Antenna Myths  
by N4JTE on July 17, 2011 Mail this to a friend!
Thank you Cecil, you have been my cyberspace elmer for a long time, my best regards.
Bob
 
RE: Antenna Myths  
by W7KB on July 17, 2011 Mail this to a friend!
Commie Ollieoxen27mhz:Please spare us the conservative propaganda.Your Gods Bush & Cheney are no longer a factor in your or my life with the exception of huge deficits run up and the biggest recession since the Great Depression of the 30's.And yes,I still want to talk antennas.Maybe even propagation and antennas.Politics and religion?..No thank you!...73...W7KB.
 
RE: Antenna Myths  
by W3TDH on July 18, 2011 Mail this to a friend!
Yes I still want to read about antennas and try to learn something rather than listen to you violate the Radio Amateur's Code. The first element of that code is that an amateur radio operator is considerate. So take your political nonsense elsewhere.

--
Tom Horne, W3TDH
 
Antenna Myths  
by W3TDH on July 18, 2011 Mail this to a friend!
Did any of you see the movie "One flew over the cuckoos nest" At one point the protagonist tries to pull a bathroom fixture out of the floor in order to throw it through a window and escape the mental institution in which he is confined. He fails in the obviously Herculean task. He then looks around and says "At least I tried." At the end of the movie after the protagonist has been destroyed one of the other prisoners does that task and escapes.

I think that publishing anything in radio is a little like that in that too many who have never tried are all too willing to criticize those that do try. But by tackling issues and doing your best with them you may inspire others to also quit carping an do something. The answer to endless arguments about antennas may lie in what our Drill Instructor would scream when someone froze during a task. "Do Something! Even If It's Wrong"

--
Tom Horne, W3TDH

Good Judgement comes with experience. Experience comes from bad judgement" Unknown
 
RE: Antenna Myths  
by N4JTE on July 18, 2011 Mail this to a friend!
Tom, sometimes I feel I am in that movie, hi, my sense of humor overtakes all so far.
Regards,
Bob
 
RE: Antenna Myths  
by W5DXP on July 18, 2011 Mail this to a friend!
> ... my sense of humor overtakes all so far.

Bob, since I'm your alleged "Elmer", my XYL says I should call you a "wascally wabbit". :)
 
Antenna Myths  
by N7AG on July 22, 2011 Mail this to a friend!
THANK YOU.
 
Antenna Myths  
by KG7T on August 2, 2011 Mail this to a friend!
GREAT ARTICLE
ITS HARD TO BEAT A DIPOLE FOR THE MONEY
AND A END LOADED VERTICAL DIPOLE IS HARD TO DEAT FOR DX.
 
RE: Antenna Myths  
by WA7VTD on August 7, 2011 Mail this to a friend!
ON4UN's book "Low Band Dxing" does not favor parasitic antennas over phased arrays; in fact, it does just the opposite (speaking here of verticals).

 
RE: Antenna Myths  
by NZ5L on August 10, 2011 Mail this to a friend!
From one old fart to another - Kudos.
 
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