Antennas

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Ampx66
Posts: 1
Joined: Mon Jan 27, 2014 12:46 am

Antennas

Post by Ampx66 »

Wondering if anyone has opinions about HF Verticals with regard to DX contacts. Until now, the only HF antennas I have used have been wire. Wires work well in the direction of their beam, but I sometimes wonder if i could cover a lot more ground with a vertical, in spite of what is known about the man-made noise factor. Any thoughts out there? 73, Joel KF7MUH
RWells
Posts: 1
Joined: Mon Jan 27, 2014 6:28 am

Re: Antennas

Post by RWells »

Hi Joel,
I would suspect that at your mean elevation at Powell Butte that a good vertical would be of benefit in DX. They generally have a lower take off angle which shoots the signal lower to the horizon, and retain a decent receiving capability.
Pick or build a good one, and do not skimp on the radial field. If you have a large metal barn or shop roof they can be quite beneficial as ground planes when properly bonded.
Eham.net has some revealing evaluations of various antennas, and as long as you use care in validating the comments made by the contributors you will get some really good insight into commercially available verticals.
It is entirely valid to assume you can build a homebrew vertical that is every bit as good as any commercial antenna, and at a lot less expense. But, if you are limited to compliance with building codes, or neighbors with concerns about appearance, a commercial antenna may be the best choice. The Spiderbeam Yahoo group has some excellent discussion on homebrew verticals, obviously based on Spiderbeam fiberglass poles, but the designs and capabilities discussed are applicable to homebrew systems using inexpensive military surplus fiberglass camo support poles too.
With a vertical antenna if you operate below 40 meters there is really no substitute for appropriate length of the radiator, so keep that in mind as you choose your solution. I have a 63 foot tall homebrew and a commercial Butternut HF9V, and the Butternut is excellent on 20 meters, okay on 40, and starts to really fall off to the point that it is not particularly good on 60, 80, and 160, and the issue is that physical size really cannot be overcome by fancy coils, capacitors, and such with a physically short antenna.
As you have stated, QRN can be a problem with verticals. There are two primary sources, atmospheric noise and industrial noise. I would suspect in your location that industrial noise would be rather minimal. Just like yagi's and wires, insulated wire in a homebrew vertical will significantly reduce noise from atmospheric sources.
73's
Randy
ku3x
Posts: 37
Joined: Sat Mar 24, 2012 5:43 pm

Re: Antennas

Post by ku3x »

Remember one thing about a 1/4 wave vertical antennas, "It's only as good as the ground radial system you install under it !"

Poor ground radial system, poor ERP.
Good ground radial system, good ERP.

If the radials are on the ground or under ground, they do not have to be tuned. My point is, maybe you have room for 1/4 wave radials in two direction but much shorter radials in the other directions.
Even though they may be only 40 feet long and you are trying to work on 160 meters, those very short radials are still important.

Commercial AM broadcast stations try to use 120 each 1/2 wave length long ground radials, if radials are used. Some even lay down copper sheets.

Bottom line, "the more you put down the better you will get out !"

Barry, KU3X
www.ku3x.net
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