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[Articles Home]  [Add Article]  

20 dB for $48.60

from Steve Katz WB2WIK on October 23, 2002
View comments about this article!


20dB for $48.60

Steve Katz, WB2WIK/6

0x08 graphic

Overview

Antennas, antennas, antennas!

They are our transducers to the ether, and are what make our wireless equipment work. Yet, for various reasons, many hams seem unconcerned about them.

Deed restrictions (CC&Rs) are probably a leading cause of hams having poor antennas, although plain old apathy seems at least as big a problem. Budget should never be the problem, since so many excellent antennas are available as used items either very cheaply or free, and of course some great designs can be homebrewed for almost nothing. And we find that often times, the ham with no antenna had enough of a budget to buy a $1000 radio. Hmph.

This subject is too vast to address in a brief article, so I'll focus on a single, popular design: HF Vertical Antennas. Even more specifically, inexpensive HF vertical antennas which are typically base-fed, trapped or loaded designs requiring a counterpoise or image plane in order to function properly. Among all the commercial designs on the market, the Hustler 4BTV-5BTV-6BTV are likely the best bang for the buck products currently out there, although Butternut HF6V-HF9V, Hy-Gain 12AVQ-14AVQ-18VS and DX88, and others can be good deals, too.

The products listed, and other popular commercial models, have one thing in common: They are not ground-independent, and have no factory supplied counterpoise. They are trapped or loaded, base-fed antennas that not only work better with radials, they work only with radials.

Any antenna can make contacts. Good ones make stronger, longer-distance contacts more reliably. With a 100W transmitter and a good antenna, many of the signal reports you receive should be `Wow, great signal - very, very strong, S9+ here.' If you don't commonly get such reports, you're definitely missing out on a lot of stuff that could be worked, but you're not going to hear it, and it's not going to hear you, either. A simple, inexpensive vertical antenna can produce such reports, repeatedly. The difference between a vertical that does get the `you're blowing me out of my chair' reports and one that doesn't is simple deployment.

50 Million Frenchmen Can't Be Wrong

That's a really old phrase, and I'm not even sure where it started - but it fits the situation. If you use modern antenna modeling software, you'll see that any current-fed vertical fed at its base, which usually means it's , or t image plane, usually made from wire radials, in order to reduce its vertical angle of radiation and reduce ground losses. When one installs such a vertical, say a 5BTV for example, on the ground without any radial system, it will generally demonstrate a good impedance match (to 50 Ohm coax), and nice, smooth, low curve plotting VSWR against frequency. That's a sure sign that it stinks.

In reality, this antenna should have a feedpoint impedance of about 30 Ohms (VSWR = 1.7 or so), and have sharp, narrow resonance curves if you plot VSWR against frequency. If the vertical has VSWR < 2.0 across the whole 40 meter band, you've got a problem, because the antenna's incapable of that. What's making the VSWR nice and low is ground loss, which appears in series with the antenna current and directly reduces antenna efficiency (both transmitting and receiving). My 6BTV is resonant at 7150 kHz, and VSWR climbs to about 3:1 at 7000 and 7300 kHz, which is about right. That's because my installation has very little ground loss - and that's because I have radials that work.

How much difference does this really make? That's a really interesting question, and although computer modeling shows the effects of radials with regard to feedpoint impedance and radiation angle, it doesn't demonstrate the real-world difference in what can be heard and worked. Simply using the antenna with easily added or removed radials (using alligator clips to attach them) is more demonstrative.

Having a battery-powered, portable HF receiver is very cool, if you're experimenting with antennas. This is because you can bring the “rig” pretty close to the antenna, and instantly assess whether a change you've made is for the better, or not. I sometimes use my little Ten-Tec SCOUT for this, but any shortwave receiver with an S-meter and an external antenna jack works. I also have an MFJ-259B Antenna Analyzer, as do, evidently, thousands of others - almost everybody I chat with seems to have one. It's a good investment.

Reality Check

Here's what I did, and have done many times. It's very interesting, and it yields great results:

-First, I installed a 6BTV vertical on my lawn, in the back yard, on a 4 feet long, 1-1/2 inch diameter pipe driven into the ground. That leaves about 3' of mast remaining above the ground, and is exactly what the Hustler assembly instructions recommend for a “no radial” installation. (In my opinion, Hustler makes good vertical antennas and gives lousy advice. Under no conditions should these antennas be used without radials, if you want to work DX.)

-I connect a short piece (about six feet) of coax to the feedpoint, and using the MFJ-259B, plot impedance data (R+jX or R-jX) vs. frequency across all bands, 80-40-30-20-15-10 meters (which is all this particular antenna covers).

-Then, I roll out four 32' long insulated wire radials, tying off the ends with plastic insulators and string to support them in position so they are laid out like sloping spokes of a wheel, spaced about 90 degrees apart from each other. I line the radials up so they can all be connected to the base of the antenna (aluminum mounting bracket), and install an alligator clip at the “antenna” end of each radial, so they can be quickly connected, or disconnected. I clip the radials to the antenna mounting bracket. (The radials slope gently away from the base of the antenna, towards the ground, but never actually touch the ground. This is an important note.)

-Next, I tune through the 40 meter band once again, using the MFJ-259B, and once again plotting impedance vs. frequency. Note the curve is much sharper, now, although the resonant frequency (where X = 0) usually doesn't change much. Also, the R is now lower.

-Then, I disconnect the MFJ-259B and replace it with the HF receiver, tuned to 7335 kHz. That's a “beacon” signal, so to speak, generated by station CHU in Ottawa, Ontario, almost exactly 3000 miles from my home. It's weak during the day, and strong at night, but can almost always be heard unless there's been a huge solar flare or other incident that just wipes out the ionosphere. I tune in CHU, and note the S-meter reading.

-Next, I disconnect the radials by unclipping them from the antenna base. If I can still hear CHU, I log its signal strength. Note, often times, disconnecting the radials causes me to lose the CHU signal altogether, making this test rather dramatic. On a typical evening, around gray line when CHU starts `pounding in' at S9+, disconnecting the radials can cause the signal strength to drop almost into the noise - a 9 S-unit change. Umm, how many dB is that? A lot. I re-connect the radials by clipping them back on to the antenna base bracket.

-Reconnecting the MFJ-259B, I tune it to 7150 kHz and observe the indication, then walk around in a circle, making each radial 2' longer, by clipping another 2' length of wire (Radio Shack clip lead) onto the end of each one. I go back to the MFJ-259B and observe the indication. Quite a difference! Resonant frequency of the antenna has dropped from 7150 kHz to 6940 kHz, completely out of the band! Well, that's about right. This verifies that the radials are tuning the antenna, and capable of changing its resonance, and the proportion change is about correct for the radial length change. Golly, does this mean that the radials are, quite literally, half the antenna? You bet it does.

-I unclip the extra 2' long leads, which were an experiment only to verify that the radials were affecting resonance. Now, I roll out four insulated radials cut to 16-1/2' long each, and perform the same set of tests on 20 meters, again using the MFJ-259B, but this time using the WWV signal at 15.000 MHz as the test beacon. This is impressive, but since I only live about 850 miles from WWV, this reception test is not a good indicator of `low angle' antenna performance: Even a very high-angle antenna will hear WWV quite well here. So, if possible, I do this test between 4:00 and 6:00pm local time during a weekday, when the ARRL CW practice and bulletins are broadcast on 14.047 MHz. The W1AW signal is strong and steady, and there for nearly two hours, so this gives me plenty of time to experiment. And, W1AW is nearly 2700 miles from me, so it's a better `low angle' signal.

-Note the differences, once again, using the MFJ-259B and the beacon signal received, this time using 20 meters. Holy cow. W1AW is S9+30 with the radials, and only S6 without them. How could that be? Of course it can be. The radials bring down the antenna's vertical angle of radiation (and also reception) to a useful angle for W1AW's signal. That means, the angle should now be low enough for working DX, too.

Try it. It's quite a test, and if you haven't actually performed a test just like this, you're doing your vertical quite a disservice.

Real Life

I couldn't leave my 6BTV mounted to a pipe on the lawn, in the back yard. The radials would eventually get tripped over and mowed down. Kids, dogs and other organisms would cause the demise of the whole system in pretty short order, here. Plus, even though I don't mind the way antennas look, this installation was pretty ugly, even to me. I scanned the horizon and found a better place: The roof of the house.

My personal solution was to install an 8' tall Glen Martin Engineering 4-legged roof tower at the peak of the roof of our single-story home; although, frankly, a cheap 3' Radio Shack tripod probably would have sufficed. I used the stronger GME roof tower to provide for the future, when I might want to put something larger and heavier up there. Then, I made multi-band radials using combinations of heavy-duty 300 Ohm twin lead and other conductors, until I had two radials for 80m; four radials for 40m; two radials for 30m; four radials for 20m; and four radials for 10m. I don't have separate 15m radials because the quarter-wavelength radials for 40m seem to work well as three-quarter-wavelength radials on 15m. (I did try, with and without separate 15m radials, and even as nitpicky as I am, could hardly tell any difference.)

0x08 graphic

Photo B: Close-up view of the 6BTV base connections, viewed looking up from the roof. I used the `radial attachment point' mounting holes in the horizontal part of the 6BTV aluminum base bracket assembly, as well as additional holes in the vertical part of the same bracket. Here you can see what appears to be nine (9) terminals making radial wire connections; in reality, those nine terminals are carrying 16 total conductors.

So, my current system has 16 radials, four per band for 40-20-10m, and two per band for 80-30m. This isn't ideal, but works pretty well and doesn't look too crazy up there on the roof. (I did, at one time, have 24 radials on the same vertical. I took eight down, selectively, and now have the `minimum' configuration that actually works.) My current radial system uses 405 feet of insulated wire. At about $.12/foot, that's a $48.60 investment to make a $200 vertical antenna actually work properly. A very wise investment, indeed.

Of course, I encourage others to scrounge, and it should be possible to come up with radial wire that costs absolutely nothing!

Alternative

For those having sufficient real estate to effectively ground-mount such a vertical, I've found the proper way to do this is to sink the base of the vertical nearly to earth, e.g., have the feedpoint within a few inches of the ground, and use lots and lots of wire radials either laying on, or buried beneath (doesn't matter) the soil. In this situation, the radials need not be resonant, but merely need to be plentiful.

Experimenting several years ago with a very large piece of property in upstate New York, and feeding a vertical against a ground-mounted radial field, I found the first few radials did virtually nothing. The next few helped. The next few helped more. And so it went, until we reached about 64 radials. After that, adding more radials didn't have much effect. In our case, we used VSWR measurement as an indication of whether the radials were actually doing their job: After about 64 radials, adding more hardly changed the antenna feedpoint impedance, indicating that we probably had enough.

Using that particular vertical, we could work global DX on 160 meters, which was the idea. Without the radial field, we couldn't hear any global DX, so it wouldn't matter if they heard us, or not.

I've found, both experimentally and also by researching others' data, that a lot of wire radials 20' long each is sufficient for amateur-band work with a ground-mounted vertical. 64 such radials would be 1280 feet of wire. I can buy a 50 lb. spool of #14 ga copper wire for about $100, and such a spool contains 3160' of wire. Thus, 1280' is about $40.50 worth. Not bad.

Summary

I have a tower and beams, too. But the vertical is a great go-to antenna, for when the beam's aimed the wrong way, or for use in a `round table' QSO. And I currently have no beams for 30-40-80 meters, so this vertical, and one or two simple wire doublets, is all I have. The vertical almost always outperforms any sort of doublet: G5RV, Windom, dipole - whatever - when working DX. Last night (August 7, 2002), I worked A71MA in Qatar `first call' on 20 meter phone, using the vertical and a barefoot TS850S. That's not `works great,' that's getting through on the first call, in a small pileup of perhaps 3-4 dozen stations I could hear calling Mohammad. With a vertical. And 100 Watts. And, oh yes: He did give me a `59+, very strong signal' report. I know he meant it, since he gave others `56,' `57' and `58' reports, right after me.

Photo C: Here is a close-up side view of the 6BTV base and some of the radial wires and attachments. I use Scotch 88 electrical tape to securely attach all the insulated radial wires to the 2 inch diameter support pipe below the antenna's base, so the mechanical strain of the wires is supported by the tape, rather than the lug terminals. The lugs and attachments last much longer this way.0x08 graphic
(In the background, a bit of my tower can be seen - it's about 50 feet away.)

Radials. They make verticals really work.

WB2WIK/6

Member Comments:
This article has expired. No more comments may be added.
 
20 dB for $48.60  
by KV7X on October 23, 2002 Mail this to a friend!
A timely article, since I am installing a 4-BTV this weekend. I won't be putting mine on the roof so will follow your advice on the ground radials.

Hustler recommends 14 ga wire for the radials - any thoughts on the importance of wire gauge for a ground mounted installation?

Also, what are your thoughts on the importance of a 1:1 isolation transformer between the antenna & feedline? Hustler suggests 10 turns of coax on a 6" diameter form.

Thanks.
 
20 dB for $48.60  
by KG6AMW on October 23, 2002 Mail this to a friend!
Hi Steve. Very interesting and informative. The photos really help to understand. I came to the assumption months ago, that radials are key to performance. The other variable is antenna location, having the antenna up and away from houses and other metal objects that may hurt performance.

You didn't comment on ground independent verticals like GAP and the Force 12 Sigma series. How would you rate the ground independent vertical against a vertical with radials? I would assume they would perform about the same. Thanks for the well written article.

Merrill
 
RE: 20 dB for $48.60  
by KC8SBV on October 23, 2002 Mail this to a friend!
Great article! Timely as well. Going to put up a 4BTV soon.

Question on long radials that cannot be run straight on the roof:

The instructions from Hustler show placing the radial in an L, straight from the antenna to the edge of the roof, then turn 90 and follow edge and attach to roof. Any thoughts on this?

Also your "multiband radials" made out of 300 ohm twin lead: Was one lead cut for a different band than the other?

TNX ES 73,
Ed kc8sbv
 
20 dB for $48.60  
by WB2WIK on October 23, 2002 Mail this to a friend!
I recommend using radial wires that are strong enough and won't break! I'm sure Hustler recommends #14AWG because thinner gauges, if pure copper, are too weak to survive the application (like walking on them). If your radials will be installed such that it would be impossible to ever walk on or trip over them, smaller gauge wires will work fine.

Re the "coaxial choke balun" discussed as a 1:1 transformer, I've never found the need, with a matched antenna. The 1/4-wave vertical discussed is not balanced, it's unbalanced, just like its feedline, so a balun is not indicated. A choke would be helpful to reduce line radiation during mismatch conditions, but I don't use the antenna under mismatch conditions, as that's a great way to blow a trap. I don't use the choke balun, although I cannot imagine it could hurt anything.

Re the GAP and F-12 verticals, they're quite different animals and I've found the ones I've used (various models from GAP and F-12) work well, but they are substantially more expensive than the simple 6BTV. This was a "For less than $50 you can really make your $195 vertical work" article. For those who don't mind spending $300+ (in some cases, a lot "+") for a ground-independent vertical, often times the whole radial requirement goes away.

Re radials "L" shaped, this is surely better than not using them. I'd do it, if faced with the space limitation.

Re the twin lead radials, this is something I've done for many years, and it's not so simple. The proximity of the parallel conductors changes resonant length, so without a dip meter or some other way to "tune" the radials to the correct electrical length, I wouldn't use the twin lead approach at all -- I'm just used to it, and do have a good grid dip meter.

WB2WIK/6
 
20 dB for $48.60  
by ZS1DX on October 23, 2002 Mail this to a friend!
Thanks for a great article Steve.

I picked up a used 4BTV for 25US$. It is mounted on top of my house. The metal roof serves as ground plane. I joined many of the metal sheets together on the inside with coax braid, and connected it to the antenna ground. This system works well, and I regularly get 59 reports from all over the world.

But it is no monobander at 100" HI. I can recommend Steve's setup 100%.

73, Chris ZS1DX
 
20 dB for $48.60  
by N9BDF on October 23, 2002 Mail this to a friend!
Steve,

I agree with everything you have said. And, any good book on antennas (like the ARRL Antenna Book) will also support what you have said. The bottom line is that verticals are viable HF antennas IF you use an appropriate ground radial SYSTEM with them.

Your experiments with and without the ground radial system demonstrate just how much of a difference an appropriate ground radial system makes.

73, Michael N9BDF
 
RE: 20 dB for $48.60  
by W0FM on October 23, 2002 Mail this to a friend!
Great article Steve. I always said that my 6BTV "worked just fine" without the radials because of the great soil conductivity we have in my area. (And in contests, EVERYONE is 5-9). With your efforts in "A/B" testing you've proven that those of us who subscribe to that theory (maybe even Hustler) are only fooling ourselves.

I had convinced myself that, if I made contacts, I was doing OK. Fact is, I didn't know what I was missing because I had never taken the time to do the tests that you did.

I can't imagine using a Yagi with all the left side elements cut off. Why would I use half a vertical? You've made a believer out of me.

73,

Terry, WFM
 
RE: 20 dB for $48.60  
by WB2WIK on October 23, 2002 Mail this to a friend!
Hi Terry (W0FM),

Thanks.

BTW, I don't know what you're using on 12m, but I heard you work ZL7C Chatham Is. on 24 MHz CW the other night, and your sig was the one that alerted me he was on the band.

I worked him right after you!

73,

Steve WB2WIK/6
 
20 dB for $48.60  
by NI0C on October 23, 2002 Mail this to a friend!
Good job, Steve, of consolidating in one place much of the practical advice you have provided to so many hams regarding vertical antennas. "our transducers to the ether" -- so true and yet poetic-- well said! And thanks for the paragraph concerning your experience with adding (and adding and adding) radials to a ground-mounted vertical. So far, I've managed to string 20 radials ranging in length from 30 ft. to 90 ft. at the base of my Butternut HF-2V (some of them had to be bent in order to stay within the property line). However, as long as there's wire left on the spool I don't think I'll be satisfied.
73,
Chuck NI0C
 
20 dB for $48.60  
by VE8NX on October 23, 2002 Mail this to a friend!
Good article!
I am just putting together a home made vertical and have been doing a bit of reaserch. Folks might want to check out the "Tech Notes" at http://www.bencher.com/pdf_download.html
 
RE: 20 dB for $48.60  
by WB2WIK on October 23, 2002 Mail this to a friend!
I've read all the notes at the Bencher/Butternut website since they've been posted there, and while they're interesting reading, they, too, contain misconceptions.

It's interesting that the Bencher "Dirty Little Secrets," "Tech Notes" and "Why Radials?" publications are neither credited nor annotated, and seem simply to target the "half-wave, ground-independent" vertical products as poor performers; but many are actually excellent performers, and they're getting better all the time.

My article didn't focus on these, at all, but for those who have the budget and the space, some of the GAP, Cushcraft, Hy-Gain and Force-12 "ground independent" products are great. The F-12 top & bottom loaded, conjugate-matched products like the Sigma-5 are revolutionary.

WB2WIK/6
 
20 dB for $48.60  
by K5YY on October 23, 2002 Mail this to a friend!
I have been around as a ham since 1957 and before that an SWL. Steve's article is simple to understand and just what we need to read once in a while on antenna theory and design. Most major points about verticals were touched on and actual "on air" results recorded. Nice job of putting theory and actual results down on paper in simple terms. My DXpedition experiences have proven that even ONE insulated wire cut to resonance for each band in use, laid on the ground and held down with a concrete block at the end will improve performance. If you can elevate the radials and feedpoint 4-6 feet the results are even better. If one uses a "bare wire" radial system on the ground, you need several, as Steve said. If in doubt or using small number of radials, go insulated route for a little more money. Also, slightly larger radial wire works better overall. In simplest of terms, use your vertical elevated 6 feet with one radial per band and you are going to work a lot of low angle contacts. If you go to 4 radials per band (elevated) you will have better current return, slightly changed resonant frequency. If you go ground mounted, be prepared for a LOT of radial work, preferrably insulated wire and many headaches! Good job , Steve. San K5YY
 
20 dB for $48.60  
by WA7NDD on October 23, 2002 Mail this to a friend!
I took 3 weeks to install my elevated 6BTV and lots of pictures. It is mounted a few inches above a steel roof, and tuned radials to the east side for all bands. The vertical was designed to tilt over for tuning. I never had to remove it from the mast to tune. The radials were designed for quick release, for tilt over but yet a solid connecton. I also installed an isolator at the base of the vertical from Radio Works and one in the shack. The 6BTV has been up for about two months and works DX very will. For really long hall DX the vertical is about 2db beter then my dipoles which are seperate, cut and tuned for 80,40,20, and 10 meters. The dipole is quite compaired to the vertical, but the vertical is hearing 360 degrees. A big secret I use is the Clear Speech base unit with my FT-920. I like it beter then the 920's DSP noise reduction. Turn it on, noise goes away, and singles pop out. On side band the voices sound a little like talking through water with weak signals, but I could not have heard them through the noise before at all. The Hustler 6BTV is a good price for what I received. I like it very much. My 6BTV is tuned on all bands, very narrow on 80, so I set it in the DX slot.
If anyone is interested in pictures I can Email them, and my SWR chart which I have since redid by some more tunning, but you will get and idea.
Jim,WA7NDD
griffithj@byui.edu
 
20 dB for $48.60  
by KA5S on October 23, 2002 Mail this to a friend!
Good article! Back in the 1970's, while stationed at Fort Hood, Texas, I put up a ground-mounted Hustler 4BTV. My _mobile_ worked better. It took 48 radials before the 4BTV worked as well as a mobile antenna on my van. Of course, "ground" there was ninety percent limestone -- laterite is no ground at all! But at least it gripped the mounting stake; I had to pound that into the dirt when I was transferred. It sure wouldn't come out.

Cortland, KA5S
 
RE: 20 dB for $48.60  
by NZ5L on October 23, 2002 Mail this to a friend!
Isn't 20 Db exaggerating things a bit? Actually, past articles along this line made more modest claims - 3 to 6 Db. That having been said, I enjoyed the article. Most hams don't realize the importance (necessity, really) of a good counterpoise for a vertical antenna. Several years ago my set-up was an HF6V, roof mounted on a 3' Radio Shack tripod with 2 sets of Butternut Stub-Tuned Radials. Signal wise, it was awfully close to the Cushcraft A4 at 27' (no F/B of course) and a whole lot easier to maintain. At XYL's insistence ("Please take that giant spider off the roof") I switched to a GAP Titan. What genuinely surprised me was that my STR kit evinced abslitely no interest at the local 'fest! Articles like this may help folks become aware of just how important the ground is in radio communications. Keep up the good work!
 
RE: 20 dB for $48.60  
by KL7IPV on October 24, 2002 Mail this to a friend!
Good article, Steve. There is another way to get the radials you need. Find, buy, or borrow a piece of 26 pair, any gauge telephone cable about 36 feet long. Strip about 2 inches from one end and make all the wires bare and twist them together. The 2 inches of bare wire will be attached to the grounded base of the antenna in whatever fashion works for you. Leave about 8 inches of outside sheath on the cable and remove all the rest of the remaining 35+ feet of covering. Leave each of the longer exposed wire insulated. Separate each of the paired wires and then fan them around the antenna. It they are fanned around a roof, trim them even with the roof edges. The wires should provide almost a metal ground plane to that antenna. The longest wire left should be trimmed to match the portion of the 40 meter band that interests you. Trimming the rest for each band should give an approximate match for all the remaining bands of the 5BTV/6BTV antenna. Cheap and it works. The 8 inches of cable sheath will allow you to fasten that to the antenna mounting pipe.
73
Frank
KL7IPV
 
20 dB for $48.60  
by NX5W on October 24, 2002 Mail this to a friend!
Good Morning, Gentlemen, Try this one out, "Dirty Little Secrets" from the "Antenna Designers Notebook". Or www.bencher.com. or "AC6V.com" and type in "Dirty Little Secrets".
By the way go also to reviews on Butternut HF6V's here at eham.net, look at what "KB5QNO" my previous call sign, had to say about these antennas. 3000 sq. ft. of a sheet Iron Roof, doesen't do too bad either, when you have the whole roof grounded any way. I have had this HF6V up in 5 different locations, all I do is put some "Noalox" ( Get this at Home Depot ) on the connections about every 2-3 years. This antenna has a 75 ohm 11' 6" tune stub on it, and a barrel connector to your 50 ohm lead. She sure works Great! After having it for 12 years.
I guess I better go catch that guy out of Tel-Aviv. I might just use this HF6V instead of my monobander. Ya'll keep on sittin' around now, ya hear? Just Kidding!
73's, Darryl
 
RE: 20 dB for $48.60  
by WB2WIK on October 24, 2002 Mail this to a friend!
NZ5L, 20 dB isn't exaggerating in the slightest.

I actually see far more difference than that, typically, on low-angle signals (3000+ miles), if I disconnect the radial system on my vertical.

As stated in the article, CHU on 7335 kHz at 0000 UTC is 20dB/S9 here this time of year. If I remove my 40m radials, it literally drops to the noise level. That's a lot more than 20 dB.

WB2WIK/6

 
RE: 20 dB for $48.60  
by WA2KWP on October 24, 2002 Mail this to a friend!
Hi Steve,

You have been very careful not to use the word "gain" in any of your comments. What you have described is an improvement in performance in a vertical antenna equivalent to 20db in signal strength received. Actually and unfortunately a vertical antenna works equally poorly in all directions with a "gain" of nothing. So if you want to get all you can in terms of performance out of the vertical that is a great idea, but you will get no gain, unless you use two, three or four verticals and feed them in and out of phase. (See the excellent series of articles on vertical antennas by Jerry Sevick, written about 30 years ago in QST)

I was forced to use a vertical antenna at my QTH in New York City. Fortunately luck came into play. The antenna is mounted 35 stories above the ground and the roof is solid sheet copper (a common roofing material on tall buildings in New York City). The roof is "grounded" to the Water Tank Piping system (the water tank itself is wood!!). I was the first in every pileup until I lost permission to use the installation (The landlord is a Neanderthal).

Thanks for an informative point of view!!!

David
 
20 dB for $48.60  
by W6TH on October 24, 2002 Mail this to a friend!
Someone wanted to know the gain of Steve's antenna roof mounted. The gain is approximately 2,736 dbi with a low angle or radiation plus an additional 3 db for ground reflections, for a total of 5+ db gain. A beam would have to be up 3/4 wavelength with 3 elements to equal this. Steve achieved the proper match by running the radials 45 degrees for a 50 ohm match.

I may add that the mounted post should be down 4 feet and 18 inches above ground for proper ground mounting the 4, 5, or 6BTV.

Nice work Steve, sounds like you are talking about my Hustler.
 
RE: 20 dB for $48.60  
by W4AN on October 24, 2002 Mail this to a friend!

re: W6TH

In my tests with a ground mounted vertical with excellent ground system (ie 60+ radials) on 20 meters... a dipole up 40 feet was always as good and mostly better than the vertical. Don't kid yourself in to thinking that an all band vertical will be better than a dipole. Unless you live next to salt water.

I'm currently in the process of laying more than 60 radials per vertical under my now raised radial 4-square for 80M. It is a lot of work, but I'm sure it will pay off. FWIW, W8JI beats me by 1 s-unit or better to Europe with his flat top dipole at 140'. That is equiv to 70' on 40M or 35' on 20M. And, this is a full sized system which provides gain (phased verticals).

73

Bill
 
20 dB for $48.60  
by W6TH on October 25, 2002 Mail this to a friend!
Hello Bill, w4an,
Steve wb2wik/6 was mostly interested in the comparison of more costly vertical antennas then the Hustler 4, 5, or 6 Band trap vertical. He chose to install and demonstrate a test of the Hustler antenna and the means to install the antenna with radials and how the radials do perform to improve the radiation efficiency and performance of this particular vertical antenna. Which by the way, has done a magnificent job in the explanation of this particular vertical.
My point of view was to say that for a certain angle of radiation will also be less costly as to installing a tower, rotator, guy wires, concrete, etc.
Many Amateurs of today do not have the finances, property etc., to go the full extent. Therefore a vertical antenna with radials may be just what the doctor ordered.

73, Vito W6th
 
RE: 20 dB for $48.60  
by K9KJM on October 25, 2002 Mail this to a friend!
My .02 cents worth...... Great article! The bottom
line is: 3 or 4 TUNED elevated radials will make your vertical work.
Once the radials come in close contact with the earth,
they are no longer "tuned" (Even a slight difference in
soil moisture can detune) And MANY more radials are
required for the same "performance"
The only point I want to make is, If you (like me)
can not have a bunch of "elevated" wire 6-10 feet
above the ground all over the yard, and must bury,
Use BARE copper wire (No reason for insulated, as close
proximity to earth detunes anyhow) And use a heavy
enough gauge close to the tower mast that it will
ALSO be an addition to your lightning protection
ground. When the soil is moist after a rainfall,
take a shovel and just "lay" the sod back, insert the
radial wire in the slit, and "stomp" the sod back.
It is easy to do over 100 feet an hour in normal soil. As others have indicated, They do not need to
all be in a perfect straight line. I have been burying
copper wire for many many years now, and is seems the
more I get in, the better things seem to work.
 
RE: 20 dB for $48.60  
by WB2WIK on October 25, 2002 Mail this to a friend!
Interesting observations, Bill (W4AN) but very much in conflict with my experience here.

In addition to the 6BTV on the roof tower with the sloping radials shown, I have the option of two 20m beams, and usually use the Tennadyne LPDA at 55', which is 15' higher than the 20m dipole you discussed and surely better than a dipole...and on many paths, the vertical will outperform the LPDA (or the 203BA), just depends on the path, and the propagation at the moment.

I could never say, at my location, that a 40' high dipole would consistently outperform the vertical on low-angle paths. It just doesn't, at least not here.

However, my vertical is not ground mounted, it's elevated and has its feedpoint sitting about 28' above ground. I agree this seems to work better than the same vertical ground-mounted with _any_ quantity of radials -- I've tried that and was disappointed.

As I'm sure you know, one can never have too many antennas and the more antennas you have per band, the longer that band works. At the contest station I usually operate, K2XR in NJ (#7 in the Top Ten ARRL Phone '02, results just published in Nov QST), we have about 15 beams up and it's definitely not enough -- all our 20m antennas are too high for the short paths into the Caribbean and western EU, and we get clobbered there.

Time for more aluminum.

73 de Steve, WB2WIK/6
 
RE: 20 dB for $48.60  
by KC8SBV on October 25, 2002 Mail this to a friend!
Steve,

Did you resonate your radials on the roof in the installed position? It seems to me to be the only way to insure that the installation doesn't change the resonate freq.

Thanks,
Ed
 
20 dB for $48.60  
by K3ZD on October 25, 2002 Mail this to a friend!
A fine article but why not just put up a dipole? They are more efficient than verticals and horizontal polarization is better anyway because it is not so ground dependent.
 
RE: 20 dB for $48.60  
by WB2WIK on October 25, 2002 Mail this to a friend!
Ed: Yes, of course I did. I use the MFJ-259B to tune the radials as part of the "system," and it goes very quickly. The older-fashioned way works, too, but takes longer!

Re the "dipole," I have dipoles. No dipole works as well as a properly deployed vertical for low-angle DX, and mine are no exception, but they occupy worthwhile positions on my antenna switch nonetheless. I also have a tower and three beams, and use them, too (as shown in one of the photographs). You can never have too many antennas, but I would not want to be without one good vertical in the arsenal.

WB2WIK/6
 
20 dB for $48.60  
by K3DML on October 25, 2002 Mail this to a friend!
Super article. Another wonderful solution to a good and cheap low angle DX antenna is a full wave square loop fed in the center of a VERTICAL side.

I can't mount a vertical on my roof but am considering suspending one from a very tall tree and adding elevated radials about 10' above the ground. Any thoughts on whether this is a lousy idea?
 
20 dB for $48.60  
by N4ZOU on October 26, 2002 Mail this to a friend!
I use the aluminum electric fence wire for radials under a Butternut HF2V vertical. A 1/4 mile roll runs about $14 and is available at any building or hardware supply store. As the wire is a silver color it's very hard to see when it's mounted above ground. Don't use it for in the ground radials, the soil will "eat" it quickly. While your looking at the wire check out the nice selection insulators available for use with the wire. I love the nail up insulators for stringing out 1/4 wave 160 meter radials through the trees.
 
20 dB for $48.60  
by K2UOD on October 26, 2002 Mail this to a friend!
I have spent the last year experimenting with a ground mounted 6BVT. The first installation was in an area with 6" of topsoil and then clay. I mounted the antenna on a 4' pipe with about 2'6" buried, no radials. It worked fine across all bands, with good success on DX.

In March, I moved the antenna to the Adirondacks. Digging through the 3 - 5' of snow, I erected the vertical without radials. It worked fine on 40, 20, 15 and 10. The best SWR on 40 was about 2:1, with a usable bandwith of about 40 KHZ. (I use a Kenwood TS830s w/o a tuner-- as long as I can tune the finals and the SWR isn't to high, I'm OK).

As we got into Spring - Summer, the antenna's performance and my ability to get a match dropped dramatically. The soil is essentially pure sand and we had an extremely dry year. Performance would improve after a soaking rain.

I started to add radials-- cut to resonant frequencies as suggested by Hustler. My approach was to use insulated two-lead AC power cord wire, with each lead cut to a different band-- two for each band. Performance improved dramatically. I laid the radials on the gound (the ground cover was brown, and we don't mow--so to me I was golden-- then the XYL saw the radial snaking though her flower bed.) I then read (probably on this board) that cutting to resonance was not essential for groundmounted antenna radials. So I added about 8 more radials, cut for 40m (CW portion). Overall performance of the antenna improved dramatically. I then buried the radials.

SWR is 1:1 on 10-15 and 20. I cannot get 30 to tune. SWR on 40 is below 2:1 in the CW portion; off the charts on 7.255 ( I have since added a 40 meter dipole for regional phone use).

I am pleased with this setup. I may be adding another vertical at the original location-- If I do, it will be the 4BVT-- with radials!

73,

Keith, K2UOD
 
RE: 20 dB for $48.60  
by K2WH on October 27, 2002 Mail this to a friend!
Great articel Steve and absolutely correct. I don't know how many times I have tried to convince hams of the necessity of radials. Their reply "But the add says you don't need them".

Anyway, I built a monoband 1/4 wave vertical for 80 meters with 52 radials on the ground. Works wonderfully. Got WAC on 80, WAS on 80 and almost there on DXCC on 80. Radials - can't live without em.

K2WH
 
RE: 20 dB for $48.60  
by ZC4BS on October 27, 2002 Mail this to a friend!
What an excellent article - I'm over the moon reading this and other comments.

Having just purchased a 5BTV and awaiting the roofers to sort out the soffets and fascia boards I will be putting it up.

After reading this I realised just how much I had forgotten/didn't know, so thankyou Steve for the "wakeup call" lol

I am not fortunate enough to have the antenna raised as my neighbours would have a sense of humo(u)r failure. But a 5' pole buried 4' deep seems to be the best solution - and of course as many "untuned" radials I can muster !!!

Thanks once again Steve - it was a pleasure reading.

Steve ZC4BS ZC40BS G4KIV
 
20 dB for $48.60  
by W3DCG on October 27, 2002 Mail this to a friend!
Thanks for this, Steve... you're turning into nearly an elmer for me at this point, you answered a question re CCRs, PB & J, and BLT I had a while back and then you do this article.

Complete with pictures. You know, at least for me, pictures are worth a thousand words at least.
I would have gotten the whole gist with the picture and your statement of:

Four radials per band except for 2 per band 30 & 80.

The reason why it almost seems like you're becoming some sort of Elmer is that, the evening before this article posted, I received my used 5btv I got for a fair deal.

Before I can even open the box here is this article.

Awsome timing at least for me,
thanks for the info-

73 w3dcg.

These are the life's coincadences that lead me to calling you something of an oracle. And it did turn out that my "Windom" really is just an OCF low dipole, too! ha! And so I have succumbed to the pressure of low angle radiation, and am going to give a vertical a whirl, despite all the hype of it's inefficiency compared to a dipole. My dipole height is maxed, at 35 feet.

TTFN.
 
20 dB for $48.60  
by W3DCG on October 27, 2002 Mail this to a friend!
Thanks for this, Steve... you're turning into nearly an elmer for me at this point, you answered a question re CCRs, PB & J, and BLT I had a while back and then you do this article.

Complete with pictures. You know, at least for me, pictures are worth a thousand words at least.
I would have gotten the whole gist with the picture and your statement of:

Four radials per band except for 2 per band 30 & 80.

The reason why it almost seems like you're becoming some sort of Elmer is that, the evening before this article posted, I received my used 5btv I got for a fair deal.

Before I can even open the box here is this article.

Awsome timing at least for me,
thanks for the info-

73 w3dcg.

These are the life's coincadences that lead me to calling you something of an oracle. And it did turn out that my "Windom" really is just an OCF low dipole, too! ha! And so I have succumbed to the pressure of low angle radiation, and am going to give a vertical a whirl, despite all the hype of it's inefficiency compared to a dipole. My dipole height is maxed, at 35 feet.

TTFN.
 
GP radials, how many?  
by W3DCG on October 27, 2002 Mail this to a friend!
Thanks for this, Steve... you're turning into nearly an elmer for me at this point, you answered a question re CCRs, PB & J, and BLT I had a while back and then you do this article.

Complete with pictures. You know, at least for me, pictures are worth a thousand words at least.
I would have gotten the whole gist with the picture and your statement of:

Four radials per band except for 2 per band 30 & 80.

The reason why it almost seems like you're becoming some sort of Elmer is that, the evening before this article posted, I received my used 5btv I got for a fair deal.

Before I can even open the box here is this article.

Awsome timing at least for me,
thanks for the info-

73 w3dcg.

These are the life's coincadences that lead me to calling you something of an oracle. And it did turn out that my "Windom" really is just an OCF low dipole, too! ha! And so I have succumbed to the pressure of low angle radiation, and am going to give a vertical a whirl, despite all the hype of it's inefficiency compared to a dipole. My dipole height is maxed, at 35 feet.

TTFN.
 
GP radials, how many?  
by W3DCG on October 27, 2002 Mail this to a friend!
Thanks for this, Steve... you're turning into nearly an elmer for me at this point, you answered a question re CCRs, PB & J, and BLT I had a while back and then you do this article.

Complete with pictures. You know, at least for me, pictures are worth a thousand words at least.
I would have gotten the whole gist with the picture and your statement of:

Four radials per band except for 2 per band 30 & 80.

The reason why it almost seems like you're becoming some sort of Elmer is that, the evening before this article posted, I received my used 5btv I got for a fair deal.

Before I can even open the box here is this article.

Awsome timing at least for me,
thanks for the info-

73 w3dcg.

These are the life's coincadences that lead me to calling you something of an oracle. And it did turn out that my "Windom" really is just an OCF low dipole, too! ha! And so I have succumbed to the pressure of low angle radiation, and am going to give a vertical a whirl, despite all the hype of it's inefficiency compared to a dipole. My dipole height is maxed, at 35 feet.

TTFN.
 
RE: GP radials, how many?  
by WB2WIK on October 28, 2002 Mail this to a friend!
K3DML: It's not crazy to hang a vertical from a tree and attach sloping radials to its feedpoint hanging 10 feet above ground. I've seen others do this, and the same setup has been the subject of a few good QST articles. Seems to work just fine, provided the radials don't strangle anybody!

K2UOD: If your 6BTV as you described won't load up on 30 meters, either you've got the length of tubing between the 20m and 30m traps set incorrectly or you've got a malfunctioning 30m trap. Since 30m is a very narrow band (50 kHz total bandwidth), the 30m tuning on the 6BTV is very critical -- if you miss the dimension by 1/4", it will resonate out of the band. If you can reach that section of tubing, try making an adjustment. If you adjust it and cannot achieve resonance in 30m no matter what you do, chances are the 30m trap is damaged. The Hustler traps are easy to damage because the aluminum "cover" is actually the trap capacitor. Any dents or dings in the covers can grossly throw off the trap tuning.

WB2WIK/6
 
RE: GP radials, how many?  
by WB2WIK on October 28, 2002 Mail this to a friend!
W3DCG, the word "inefficiency" is really misplaced when describing most antennas, and most all vertical antennas.

Energy applied to an antenna must be radiated or dissipated, or converted to light, sound or motion, which I don't think any antenna can do. So, it's pretty much radiated or dissipated. If it's dissipated, the energy is converted to heat. How hot does your antenna get? Mine don't even get slightly warm, no matter how much power I run (even 1500 Watts RMS), so I think the "dissipation" thing is out.

The energy is radiated -- virtually all of it. Thus, most antennas, and surely the kinds discussed here, are nearly 100% efficient. The difference between an "efficient" 1/2-wave antenna and an "inefficient" 1/2-wave antenna is found in positive signal reinforcement created by ground reflection, or pattern arrangement which can be altered by design and deployment.

This article focused on proper deployment only; there are lots of other variables. But I think most all antennas not containing resistors (and some do!) are close to 100% efficient.

WB2WIK/6
 
RE: GP radials, how many?  
by NI0C on October 28, 2002 Mail this to a friend!
Steve,
I think "efficiency" with regard to verticals (at least the ground-mounted variety) has to do with the heat loss in the earth itself. The ground-mounted vertical has been modeled as two resistors in series-- one representing the radiation resistance, the other representing the ground losses. More radials reduce the ground loss resistance, but you can never get that to zero, hence the efficiency factor. (I've been looking at the chapter on vertical antennas in ON4UN's excellent book on low-band DXing.)
73,
Chuck NI0C

 
20 dB for $48.60  
by KC9BZN on October 29, 2002 Mail this to a friend!
Great article and perfect timing for me. I will be putting that same vertical up on my roof this coming weekend and plan to put out 4 radials per band. My installation will be very similar to yours so let me ask you a couple of questions. First is your vertical ground mounted for lightning, the mast, tripod, coax, lightning arrestors etc....If so how did you do that and what does it do to the performance? I live in Indiana and a lightning strike to the center of my roof through a vertical antenna with no place to go is scary.

Second question is I can clearly see from your pictures how the radial wires connect at the base of the vertical, how are they connected on the other end to the roof and did you insulate the ends???

Thanks again, great article...

73's
Brian
KC9BZN
 
RE: 20 dB for $48.60  
by WB2WIK on October 29, 2002 Mail this to a friend!
Re grounding: I have a reasonably large ground cable (#2 stranded copper) from the aluminum roof tower which supports the Hustler to an 8' ground rod driven into the earth below the antenna. This is a far shorter, and lower resistance, path than my coaxial cable provides to the station (that path is 85' long and not in a straight line), so chances are the ground cable would divert most EMP energy from a nearby lightning strike; however, we don't get much lightning around here and the theory hasn't been tested.

If you're in a lightning prone area, I'd follow the recommended guidelines for grounding, just as with any exposed antenna.

The ends of all the insulated radial wires are terminated in molded insulators, then tied off with lightweight (twisted nylon) ropes to hookeyes in the corners of the roof. The wires never touch, or even come particularly close to, the roof. Their ends are all suspended above the roof by at least 24" -- the shorter ones are suspended higher than that.

73 & good luck with the installation!
 
RE: GP radials, how many?  
by WB2WIK on October 29, 2002 Mail this to a friend!
N0IC, I agree completely regarding ground-mounted verticals of this design, and am happy I was able to install mine considerably elevated, with tuned radials. Huge difference.

Although, some ground-mounted verticals will have almost nil ground losses, by design. The Sigma-5 is such an example, but it's not a base-fed 1/4-wave, which is what the article was all about!

73,

Steve WB2WIK/6
 
elevated wire vert.  
by K3YD on October 29, 2002 Mail this to a friend!
[to K3DML] The concept of a wire vert. hung from a tree is what I used at my last QTH. I cut the antenna for 20 meters (16.5'), used 4-radials and fed the antenna with 450-ohm ladder line. Using a Matchbox I was able to load this antenna on 20, 15, and 10 meters. (The antenna was based on W1AB's scheme in QST about June 1999 or June 2000.)

My feedpoint was about 14' above ground with the radials sloping down to 9'~10' above ground.

I put this antenna together, and hung it, in about 2 hours. Running 50 watts (TT Argosy) in the 2001 CQWW-CW I worked over 80 countries in about 6 hours. My cost for wire, feedline and insulators was about $35. (It could have been cheaper, but I splurged and used a Ladder-Lock insulator as a tie point.)

Unfortunately my current QTH lacks a tall tree to duplicate this great antenna.
 
20 dB for $48.60  
by N7XB on October 29, 2002 Mail this to a friend!
Steve:

You wrote, "When one installs such a vertical, say a 5BTV for example, on the ground without any radial system, it will generally demonstrate a good impedance match (to 50 Ohm coax), and nice, smooth, low curve plotting VSWR against frequency. That's a sure sign that it stinks."

Wow . . . I thought my new 6BTV ground mounted without radials was doing perfect, since the VSWR was <1.5 all across 15 meters and nearly so on 20M. But this new replacement for the old 5BTV (with radials) didn't seem to "reach out and touch" the DX like the 5BTV.

Now I know why!!! I reinstalled the radials today and the 6BTV got a lot noisier when listening (yippee!!). The VSWR flat line turned into a nice smile again, and as an added bonus, my "sweet spot" on the 80 meter coiled stinger (3.580 for psk31) is now <1.3 @ 95 watts without any help from the FT-920's tuner. It used to be >2.5 @ 55 watts auto-reduced.

Thanks again for the great article, especially the enlightening tidbit about a "nice, flat VSWR across the band."

73 de Bruce, N7XB
 
RE: GP radials, how many?  
by W3DCG on October 30, 2002 Mail this to a friend!
Well this is good news to this prospective Trap Vertical user! We all want to hear our antenna system or the one we're planning to deploy is "efficient" and will work well. I've wondered about the "efficiency" question since I heard terms like cooking earthworms, cloud burners, etc etc. But I suppose if one's signal is cooking worms, the radiation efficiency must be high, the radiation pattern might need serious adjustment/re-alignment :)

I mention the words -inefficiency- and -hype- in the same sentence, because of course competing manufacturers will have the world believe that the Hustler series would be inefficient, with loss gained in each TRAP, so by the time you get to 40 and 80 your precious RF energy has gone through at least 4 or 5 Traps, each trap contributing to loss, probably in the form of heat.

Perhaps not a big deal if you have an amp, but I don't nor do I plan on aquiring one any time soon.

And yet you read of many people's real world experiences where very many seem to agree that the Hustler base HF trap verticals work very well when installed properly. Another private study had determined that the -BTV series Hustler trap vertical measured performance which was less than the equivalent, non trap Butternut. And both the Hustler and Butternut were superior to another super-multiband-NO*RADIAL-NO*TRAP-elevated-top-feed vertical. However, the difference between the Hustler with traps, versus the Butternut without traps, was not significant, and the on air difference would be seldomly heard. So then what's all the hype about traps zapping precious energy. Evidently they do zap energy that may have otherwise been radiated, but I also know I am not inclined to be raising a 66 foot quarter wave ground plane on my roof. And yet that would be more possible than suspending over a hundred feet of wire horizontally 120 feet above my tiny city lot.

I was mentioning efficiency with an evidently less than favorable connotation toward verticals vs flat-top 1/2 wave dipoles (implying that also these dipoles are 1/2 wave up).

Yes, I was, primarily because I've seen studies that suggest 4 radials are good but 8 radials are best, for a quarter wave elevated vertical. Supposedly at 8 resonant radials the efficiency approaches that of a 1/2 wave centerfed wire. Several different studies seem to agree that with regard to ground mounted 1/4 wave verticals, 60 radials appears optimal. But how does this efficiency relate to performance?

Dare we start this horizontal vs vertical debate again?

Perhaps there would be no argument if when ever we compared 1/4 wave Verticals to 1/2 wave dipoles, it would always be with the implication, that the 1/4 vertical has 60 quarter wave radials if GND mounted, or 4 quarter wave radials if elevated high enough to achieve a nice slope. And the dipoles, are assumed to be 1/2 wave, center fed, flat-topped at or close to 1/2 wave high minimum.

Do I really want to just work only DX, or am I really hoping to Ragchew with the vertical, from the S.East to the N.West U.S.? I love the idea of DX ragchewing, learning about other places and cultures and people via radio, however- how often is that opportunity actually presented on the air? Perhaps it occurs more frequently on digital and phone?


Although I find the debate amusing, at this point, I just want to know,

that if I get my 5btv up 20 feet, and can manage to install 4 radials per band 10/15/20/40, and two for 80, that my signal will be good from Georgia to the West Coast and perhaps to the mid Pacific, and a little past the fringes of Europe on 40. 40 meter DX 569s would have made the effort and investment worthwhile, as in I'll have gained performance over my current horizontal wire, and 589s from out West would be phenomenal so I don't expect THAT kind of domestic DX performance but a Low Power solid 579 from the West Coast would be a beautiful thing on 40.

I'd be doing the Safety Dance around the pole under a full moon, dancing around my antenna, aspiring of course to not to fall off the roof or catch my neck on a radial as if in some kind of pagan harvest ritual.

Actually, I was wondering how the antenna would perform with only 2 radials per band on 10/15/20/80, with 4 on 40? I heard rumors that Hustler recommended this sort of set up, but I got my vertical used and I don't think it came with instructions, or "manual," pamphlet, or other enlightening literature.

So naturally, I would imagine anyone considering an elevated mount, is going to be curious about the practical on air difference between 2 radials per band and 4 per band except for 30 and 80 where there are two radials per band.

In pondering the question of whether or not to go vertical, I've often thought my little bizarre OCF dipole worked well enough on 10 and 15, even on 20, it's no multi-element array, but every so often it works surprisingly well, perhaps to stations within major lobes...

I was feeling a need to go vertical for 40 and 80, because I can't get a horizontal wire up past 35 feet, and have no choice but to align it East/West to boot.
This of course having not much if any thing to do with efficiency. But wait!

Having the option for instant band changes on at least the classic bands sure would come in handy on some weekends. So probably doing 18 elevated radials on a 5btv would be worth while, I just can't help but wonder the practical difference between 2 and 4 radials on the higher bands.

Again, sound advice is much appreciated,

w3dcg 73.


 
20 dB for $48.60  
by KH7L on October 30, 2002 Mail this to a friend!
Great article Steve. I've used the past 2 years a Hi-gain 14AVQ with 4 radials per band elevated. I pound a 5 foot pipe into the ground 4 feet, then use a pipe to pipe clamp and attach a 15 foot pipe and the vertical on the top. The radials end about 5 feet off the ground.

I don't have tall trees or a tower to put a dipole 1/2 wave up. This with a 100 watt rig is what I contest with. I live in the mountains, 5 miles from the ocean.

Rod KH7L
 
RE: GP radials, how many?  
by WB2WIK on October 30, 2002 Mail this to a friend!
W3DCG: I can't predict how your proposed installation will work, and I don't think anyone else can, either.

I recommend you do what I always do, which is install it, test it, prune it, test it more, and work on it until it's the best it can be. I find out how many radials will work by measuring results, not by any prediction or model. And the "measured results" include, as mentioned in the article, checking R and X values at the feedpoint using the MFJ-259B, adding radials until those no longer change, and then stopping. Whether that will be two radials or fifteen, I really never know until I try.

I also trim radial lengths to resonance by measuring the antenna's feedpoint X and adjusting radial lengths until X = 0 at the frequency I want to center on. This is typically _not_ the "calculated" length, although it's usually pretty close.

Anticipating what DX might be worked with any given antenna is a time-waster, in my opinion, unless one has nearly limitless resources to design optimum systems. For example, at my contest station where we have 11 acres of open mountaintop space to play with, and five towers already there (with the option for more), we can install multiple yagis at various heights, which _always_ works better than just a single yagi at any height. It's a given, there's nothing to calculate. More antennas, more options.

The average "home" station has fewer options and should experiment the best he can within space, time and budget constraints. That's what I do!

WB2WIK/6
 
20 dB for $48.60  
by N2DUB on October 30, 2002 Mail this to a friend!
I just put this same antenna up recently, and I found that your comments reflect my experience with this antenna exactly. It's absolutely the best bang for your buck in any HF antenna, but you have to put up radials. I roof mounted mine on a homemade chimney mount (no, not those shiny old straps for TV antennas) made of four short angle irons and two heavy duty threaded rods, creating an assembly that easily clamped to the brick chimney without any fasteners. Where the angle iron extended away from the chimney I attached U-bolts for the mast. Since the 6BTV base fits perfectly on 1-1/4" pipe (PVC or iron) I used a ten foot 1-1/4" pvc (sch. 40) with a ten foot 1" galvanized pipe inside it for strength. This brought the base of the antenna up to about 40 ft (where the signals are!). The radials for 10, 15 & 20 meters were easily secured to the gutters using insulators and nylon cord. Radials for 30, 40 & 80- meters were run to trees around the property. Decent resonance was seen from the get-go, but fine tuning the radial system is key, particularly on the higher bands like 10, 15 & 20. You have to be patient and willing to experiment with the radials to get this antenna working optimally. I'm still tooling with mine, but in the last six weeks I have worked over 75 countries barefoot on cw & ssb with good signal reports. In conclusion, even if I get a Yagi up, I'm not taking down this versatile antenna.
 
RE: 20 dB for $48.60  
by KC0JBJ on October 31, 2002 Mail this to a friend!
Anyone have any experience with an Off Center Fed (OCF) trap vertical? A friend of mine had a Hy-Gain DX-77 (10-40 meters, with WARC), which its manual explains is an OCF or "Windom"-type antenna, but in a vertical configuration, while most OCF or "Windom" antennas are wire antennas, horizontally mounted. My friend had good experience with his, mounting it on a pole on his deck. He only sold it because he decided to replace it with a compact beam for higher gain/directivity.

Knowing that in my neighborhood, while not CCR restricted, a beam would get too much undesirable attention, a vertical mounted in my back yard would be less objectionable to the neighbors, and unseen from the front. So when my friend decided to sell the DX-77 I jumped on it.

However, now I am wondering, have I made a mistake? Yes, it is probably just as efficient as any other vertical, but "performance", especially for DX, has more to do with its low-angle radiation pattern, which is another reason why ground-mounted verticals are often chosen when it is difficult or impossible to get a wire high up into the air.

So my question is, how does the DX performance of the OCF Vertical (no radials, they would de-tune the antenna) compare to the 1/4-wave vertical with a moderate number of radials? Has anyone ever done a study of their relative gains?

Just wondering if I should go ahead with my DX-77 installation or switch to an antenna such as described in the article. Of course, I am lazy and prefer no radials if the perforamance is anywhere near comparable! <grin>

73 de KCJBJ,

Don

 
RE: 20 dB for $48.60  
by WB2WIK on October 31, 2002 Mail this to a friend!
It's difficult to predict, but in general I've found elevated HF verticals with radials outperform ground-mounted ones, with or without radials.

But, since you evidently already have the DX-77 and intend to ground-mount it, that certainly isn't much work. I've put up countless ground-mounted HF verticals over the years and it never takes more than about two hours, separated by a few days:

1. Dig hole, plant mast with redi-mix concrete filling hole;
2. Wait a few days for concrete to cure;
3. Install antenna on it!

Couldn't be much simpler, or much cheaper (mast and redi-mix might cost $10 for both items), so why not just put it up and see how it does for you?

Problem is, of course, I'm never satisfied (and I think no one should be) with a single antenna that "works great," because "great" could be horrible, and I'd never really know without any standard of comparison. I might be 20/S9 in Malaysia, but is that a "works great?" Or is that the same report he gives everybody, and as soon as the going gets rough, I'll be buried? Is it the same strength I'd be with a dipole in the attic, or the same strength as I'd be with a small beam? Or with a dummy load?

Who knows?

This is why I never have "one" antenna for any band, if there's an opportunity to have two or more!

WB2WIK/6
 
20 dB for $48.60  
by N0OR on November 19, 2002 Mail this to a friend!
Great article. I used a 5BTV in the 80's and roof mounted with a Radio Shack 3' roof mount. I had 4 radials per band and they sloped down. This antenna worked lots of DX with 100 watts.

Jim
 
20 dB for $48.60  
by WA2UBY on December 3, 2002 Mail this to a friend!
Another way to add radials is to use fiberglas guide wires and wrap some wire at the 1/4 wave resonate frequiency around the guide wires. Then the guide wires have 2 uses.
I made a simple neat vertical ground plane antenna out of PVC pipe. I work for Home Depot and we throw out the cut and scrap pipe. They only sell the pipe in 10 foot sections, some customers only take a few feet but pay for 10 feet, we will cut the pipe and we throw the remainder out. Being a good ham scrounger, they let me have the scrap, instead of it going into a landfill for the next thousand years. I made a simple 2 band ground plane vertical by running a #8 copper wire (6 cents a foot) inside a 1" PVC pipe, made a hole in a cap (22 cents), put a washer on top and sealed it with phenoseal. Glue-on but not glued, couplers attach each section together with a scrapbox jack and plug BNC in each section. In a 4 way coupler I put a BNC connectors that also held the radials. the bottom was a hunk of 2" PVC with a cap, that the radials and vertical element fit into for travel. total cost $4.78. I get some loss in the connectors, but for what I use it for, it works fine. I still use it when I go on vacation, on 10 and 15 with pretty good results. The SWR really isn't that critical. It does the job, and sits in a corner of the garage when not in use. Use a little imagination and experiment. Thats what being a ham is all about.
 
20 dB for $48.60  
by KD5QEF on March 17, 2003 Mail this to a friend!
Mr Katz;

Thanks very much for this radial/6BTV article! Very informative, thanks for sharing your research. This
is very helpful.

One question; How did you attach your radials at the distal ends? I am wondering since your 6BTV is roof mounted, in what pattern should the 16 radials be laid out (equidistant or not) and what did you attach the radials to at the far ends (nearby trees or the roof itself?). You cite having 16 radials but in the photo I see only about 8, so I am wondering if some are bundled but insulated from one another (or am I seeing things)? I think maybe you are saying your grid-dip meter and twin-lead allows you to bundle radials?

Thanks,
-Nick KD5QEF
 
RE: 20 dB for $48.60  
by AF4K on May 25, 2003 Mail this to a friend!
Can you tell me WHY Hustler are SO adamant about using
1 four foot long mast at the base and why they are SO insistenmt that you NOT concrete it into the ground?

I was hoping to install my 6BTV ground-mounted with a
good number of radials under it. Until I read the instructions it seemed logical to have a strong secure base that was concreted in. Now I read that you MUST use guy wires etc. etc. I can live with using some insulating guys just above the 20m resonator, even though it will make mowing the yard a royal pain...
What I had wanted to do was use two 4 foot ground rods adjacent to the base, plus a radial wire system as described by many in this discussion.

Is there ANY good reason why I should not concrete the mast into the ground if I am using the radials and the ground rods?

Thanks for a GREAT (and timely for me) discussion on the 6BTV.

- Brian, AF4K
(at ARRL e-mail)
 
RE: 20 dB for $48.60  
by AF4K on May 25, 2003 Mail this to a friend!
Where can you buy fiberglass guy materials?

Thanks in advance - Brian, AF4K
 
20 dB for $48.60  
by K3GM on May 17, 2004 Mail this to a friend!
Great article, Steve. I'm in the process of installing a ground mounted 5BTV at my new QTH. I have several acres of forested land and at this time, don't wish to clear it for a tower. After choosing, and clearing a 70 foot diameter circle amongst the large trees of organic debris, I have begun to lay out an extensive radial field using about 3000 feet of 16GA soild, insulated wire. To secure the radials, I have used a galvanized nail at the end of each radial. Additionally, to keep the wire flat against the forest floor, I made countless "U" shaped staples from galvanized wire that are placed anywhere the radial may lift itself from the ground. I have a lot of work to do before activating the antenna, but I expect it will do a respectable job. I had to chuckle at a previous comment where the author said, "Actually and unfortunately a vertical antenna works equally poorly in all directions with a "gain" of nothing." But in the next sentence says he was first in every pileup. Go figure!
 
RE: 20 dB for $48.60  
by WA8MCQ on March 18, 2005 Mail this to a friend!
While working with Steve to get his article into the QRP Quarterly, I noticed a section near the top that got mangled somewhere along the way. He later told me that it happened during the translation from a Word document to HTML. The second sentence under the heading "50 Million Frenchmen Can't Be Wrong" had some words cut out. Here's how that paragraph should read, according to Steve--

"That's a really old phrase, and I'm not even sure where it started - but it fits the situation. If you use modern antenna modeling software, you'll see that any current-fed vertical fed at its base, which usually means it's wavelength long electrically, will require as part of its design an effective image plane, usually made from wire radials, in order to reduce its vertical angle of radiation and reduce ground losses...."
 
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