Richards wrote:
> Good Day Tower Talkians --
>
> I am trying to select an antenna to install before the winter arrives.
> I live in Michigan, and have a smallish, 100' (N-S) x 55' (E-W)
> suburban backyard that has a bit of a hill in the back, and a
> trough towards the house and back deck. Cost is not a limiting
> factor. Wife says a tower is OK - and would rather have a tower
> than have holes in the roof. City says tower based antenna can
> be 55 feet tall with no need for permits, or inspections, carte blanche,
> but higher will entail fighting City Hall. Wife would like to avoid large
> radial ground wire field, but understands it might be necessary.
>
> A couple of photos of my location/situation RF can be seen here:
>
I've used a number of verticals and each type has it's pluses and minuses.
I do not like the tall verticals that are loaded on all bands as the RF
for the higher bands is radiated at too steep an angle. They also
require a pretty good radial system. I do like 1/4 wave 75 and 40
meter monobanders and a 75 meter vertical loaded to run on 40 gives a
good angle of radiation. It becomes a voltage fed antenna on 40
The AV640 works better when elevated, has lots of parts, (I wouldn't
call it expensive), some find it confusing to assemble and it does take
a while, but the manual is pretty well written. At 32' it works quite
well on 40 as long as it is kept well away from metallic objects and at
least 5' above metal roofs and ran gutters. A sloaper 40 ' away
noticeably detunes the antenna on 40, 20, and 15. It doesn't seem to
bother it on 10 or 6 meters. SWR is very low mounted on top of a 32'
aluminum tower. However putting it up 40' changed the tuning and
minimum SWR. As the bands are individually tuned via stubs and top hats
tuning one band does not affect any others. It appears to be fairly
efficient for a multi band antenna. Signals are closely comparable to
a center fed, half wave sloper at 60 degrees with the center at roughly
60'. The problem with the comparisons is the 5 minutes it takes to
raise and lower the sloper.
> http://picasaweb.google.com/MINIRichards/MyBackyard?authkey=Xq6wDhnEoXY#
>
> I have considered a tower, but that is not going to happen this
> year. That is a 6 month project, and I am not far enough along for
> that. So, in the mean time I am considering putting up a vertical
> antenna of some sort. I will augment that with whatever wires I can
> also hang to give me multiple options and something to measure
> against.
>
The Hytower is probably the most efficient of the whole group IF you
have the room for a good radial system.
> I now have a 40 M half wave dipole, and an Alpha Delta DX-EE
> multi band, trapped dipole covering 40-20-15-10- etc.
>
>
I dislike trap dipoles even more than trap verticals.
I've found most multiband verticals do require guying even when they say
they don't if you have much wind at all. This is particularly true with
trap verticals, or even a monopole over 30 feet. I even guyed the AV640.
<snip>
Roger (K8RI)
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