AA8IA Amateur Radio

HF Vertical Antenna Considerations

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I’ve been looking into various options for multiband HF operation.   The cheapest and easiest [typically] would be a variety of dipole fed with ladderline.   The problem is my lot size.    The whole lot is 100×150, but the house, side yards and front yard occupy 75×150 and the remaining 75×150 is occupied by a back deck, underground utilities, a fenced in area for the dogs, and a small portion of wooded area — no trees at all on this part of the property.

Over the years I’ve used various wires, and they always performed better than nothing but they never performed, mostly due to me never having an option to put them up at a proper height or with a proper length to work all the way down to 80m.   Forget about 160.

So I’ve been looking at various verticals.   Some pros to a vertical is that you often can fit them into a space that a wire cannot fit, and they have a low takeoff angle so they are fairly decent DX antennas.   Some cons are the fact multiband verticals tend to be long and sometimes cannot handle the abuse that a high wind area poses; also many require a radial system, and constructing a proper radial system [especially if you are ground mounting a vertical] is not for the faint of heart.

Option #1:  Ground-Mounted Vertical

A Hustler 6BTV falls into this category and would be my vertical of choice if I was able to ground mount it.   I typically would not have had an objection to a ground-mounted vertical.  However, GMVs require a proper ground system to work as advertised.    Just because a vertical may tune up with or without a tuner without the use of radials doesn’t mean it’s radiating the signal where it is most useful.   I’ve been doing a lot of reading about radial systems, and although I would not object to going through the trouble to install a proper radial system, it’s just not in the cards.      It is recommended that a GMV be located at least 20 feet away from tall frees, houses, metal structures [including fences].   It is also recommended that the ground system consist of at least 20 radials cut to at least 1/8 wavelength on the lowest band that you wish to operate (33 feet for 80m and 16 feet for 40m).

In the area where I could possibly install a GMV there is a fence surrounding it within 15 feet of the location and a septic system and underground electric beneath it.   I could never lay out a proper ground system with the fence in place, may have trouble with interference from the underground electric, and would certainly have a problem with the chain link fence being in close proximity to theantenna as well as the house and tall trees just beyond the property line.

Option #2:  Elevated Vertical without Radials

I’m not sure how well this category of verticals works, but one antenna in this category is the Hy-Gain AV-640.    This antenna is an 8-band vertical (80/40/30/20/17/15/10/6) that does not require a radial system.   It is 25-1/2 feet tall and weighs 10 lb.   I’ve read good reviews and bad reviews.   The bad reviews included reports of missing parts upon shipment, sometimes shoddy craftsmanship (holes not lining up, burs around machined edges), water intrusion into various parts of the antenna system where it does not belong, etc.   Good reviews include the fact that it is easy to put together, easy to work on, works very well on 10m-30m whilst being somewhat of a compromise on 40m, is easy to tune, and that is pretty good at withstanding the wind.

An Antenna like the AV-640 is more of an option for me.   However, I’d still like to get it up in the air.   I don’t have a tower, but i believe I have the needed real estate to erect something and will likely pursue that.   I’d mount an AV-640 elevated, but not with a height clear over the top of the house at this point.

Summary:

Obviously the low takeoff angle bothers me for working local, but unless you have money and available real estate you can’t always have your cake and eat it too.   I like working predominantly the state QSO parties / contests and Field Day.    I do occasionally participate in other contests that are worldwide.

I do like the vertical because it takes up minimal horizontal space, doesn’t require wires strung all over the place, is easy enough to construct and put up, and is easy to maintain.

I’m likely going to go with a vertical that does not require a separate radial system such as the AV-640 (but perhaps not the AV-640 when all is said and done).   When this will happen, I am not sure.

Written by Mike

April 6th, 2010 at 8:52 pm

7 Responses to 'HF Vertical Antenna Considerations'

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  1. You mention that elevated verticals using no radials will work but not great. Now your yard space is limited how can you put down radials 1/4-1/2 wave lengths long at ground level and why dig up a nice yard to do it? Now on the other hand a no ground plain antenna must up at least a 1/2 wave length high to work. I think may be if you put up a vertical above ground level and using a good system you may get a way with it.

  2. David,

    I’m no expert. But, I know that a 1/4w vertical is going to require a radial system. If you are going to ground-mount a 1/4w vertical, then the radials do not have to be tuned [cut for band] but should be high in number (32-64 a 1/4w in length for the lowest bands you’ll be operating). And if I were to raise the vertical more than a foot off the ground, I’d have to have tuned radials [cut specifically for 1/4w on EACH band that I plan to operate]. So raising a quarter wave is more trouble than it is worth for most people, including myself.

    You can do a 1/2w vertical, but I believe the pattern and take-off angles are completely different on 1/2w verticals. I believe, from my reading, that a 1/4w vertical is the better DX antenna. So that leaves the choice of ground mounting with a ton of radials as long as possible and as numerous as possible (up to a 1/4w in length for the lowest bands you are going to operate) or a raised 1/4w vertical with tuned radials for EACH band that you are going to operate.

    For those wanting a single band, it’s a little easier. For those wanting multiband performance, then a raised 1/4w vertical is going to require a lot of tuned radials, sloping down at proper angles.

    For me — a raised 1/4w vertical isn’t going to cut it because I’d have to find anchor points for the sloping tuned radials of each and every band that I was going to operate the multiband vertical on. I don’t want to put up a single-band vertical. I need all-band performance.

    Like I said, I’m not claiming to be an expert.

    Mike

    30 Aug 10 at 11:49 AM

  3. Ka7niq here OM, why not mount the Hustler Vertical antenna on a chain link fence pole like my friend does here in Tampa ? He had his antenna roof mounted, but when he lowered it, and used the chain link fence as a ground, it worked far better for DX then when it was on his roof.

  4. Hi Chris. Well, to be honest — I don’t currently have a vertical up. I haven’t ruled one out, but I’ve been weighing options. Of course, if I keep weighing options like I am now, it’ll be years before I have an antenna other than a doublet up. When I was thinking about the vertical, I remember reading of many people who did just what you suggest. Of course, there were always others that said that you don’t want your vertical near any other metal objects because (a) it would distort a pattern and/or (b) cause RFI problems. Well, I gave up on the idea at the time because of those reasons.

    I’m still thinking seriously about a hexheam. I personally think they are one of the ugliest antennas known to man, but they are apparently pretty light and durable. Of course, if I purchased a hexbeam I’d want to at least have it up 25′ in the air. And that would require that it be more visible to neighbors and also would require that I have a better support system than I have now for my wire.

    Time will tell. For now I’m running the 80m V doublet on a 35′ support and the Alpha Delta DX-EE between a tree and the porch railing.

    Mike

    1 Apr 11 at 10:34 PM

  5. Found my well radialed gnd mtd vert not well suited for neighbors.Had signal ingress trouble on 75m lsb and 40m am.20m thru 10 not a problem though. After going to horiz dipoles, no more trouble.

    Lane, n8aft.

    5 Oct 11 at 1:22 AM

  6. I haven’t used a ground-mounted vert in a long time. But I’ve had that happen before as well. It makes a lot of sense that it could happen. My dipoles do not cause problems for the neighbors, at least not that they have told me. But due to the dipoles’ low altitude and close proximity to the house radio room, I do get problems from time to time with RFI. Not too bad. Rarely on 40m. Sometimes on 80m SSB depending upon the headset I’m using . I don’t use 160m, but I’d guess that I’d probably end up triggering GFCIs at my house and my neighbors house on 160m. Although it’s possible that some of it is coming down the coax, I really suspect it’s simply due to the antennas being so close to the shack. Both dipoles are are less than 30 feet from the shack.

    Mike

    5 Oct 11 at 9:28 AM

  7. A correction for you the Hy-Gain av-640 is not a 80 it does (40/30/20/17/15/10/6) meter antenna the av-680 now has 80 added and it does (80/40/30/20/17/15/10/6)

    Mitch

    22 Nov 13 at 9:01 PM

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