On 11/13/98 10:28, LUST AUCTION SERVICES - Verona, WI at
rlust@madison.tds.net wrote:
>SO, thought I might struggle through the winter with a temporary
>ground or roof mount all band RADIAL-LESS (no room for radials!)
>vertical -- have read specs. on Cushcraft's R-7000+ (w/R-80 80 mtd.
>extra kit) --
>
>Any opinions? Good or bad, pro or con -- NOTE that I have never
>used a vertical before but wish to use such a multi-band just to get by--
I've been using an R7000 for my primary antenna for 2 years.
It works OK. It does well on 40m, and works passibly on 20-10. I haven't
used it much on the WARC bands. On 40m the low angle of radiation is
evident. Of course, on 20 and higher it is not a beam.
I have mine mounted on a 7.5 foot high on 1.5 inch rigid conduit. This
isn't the best mast material. I recommend something with a larger outside
diameter. a 2-inch OD mast would be perfect. 7.5 feet isn't an optimal
hieght. Art (formerly with Cushcraft) told me the antenna was designed to
be mounted about 18 feet high. Higher doesn't help, but lower than 8 feet
can cause problems.
The usable bandwidth on 40m is kinda narrow. If you have an automatic
antenna tuner, you'd never notice. I didn't opt for the R7000+ because a)
I didn't want to put radials in - the 80m kit requries three 20 foot
radials and b) it reduces the usable bandwidth.on 40m, and the 80m
bandwidth is really small.
I tried to tweak the tuning of my antenna, but found the interactions to
be somewhat complex. Again, if you haven an automatic antenna tuner, I
would just set it to the factory settings and leave it, except perhaps
for the top 40m adjustment.
>Thanks for suggestions --
>
>If I was to use the R7000+, would you suggest ground post mounted
>(on fence type support?) or roof top or at the top of 80 ft. tower??
A ground post would be fine, so long as it is about 10 feet tall or so.
My 7.5 feet isn't quite optimal.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@radio.org
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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