On Jun 1, 2006, at 12:12 PM, Darwin, Keith wrote:
I'm thinking about getting one of these 20-10 verticals to put on my
roof. I want something that covers 20-10 including WARC bands. I had
an MA5V which worked OK but the bandwidth was terrible and tuning was
way too touchy! Yuck.
Having done a lot of research regarding verticals I'm rather
untrusting
of the "no radials" lie that Cushcraft and others keep pushing.
Sorry,
but no radials means you have a lossy return path. Still, these
antennas, with their short stubby radials, have the advantage of being
mountable on a pole some distance in the air which helps ...
So, anyone here have or use one of these? Do they work great? Are
they
a waste of money?
K7LXC and N0AX published a report a few years ago where they compared
several vertical antennas. They didn't use radials, but had a ground
screen with the antenna (IIRC) 7 feet above ground. The report is
available (for purchase) from <http://www.championradio.com>. When I
was looking for a suitable vertical after moving to this QTH, I
bought a copy and it has a LOT of comparative data (they also wrote a
similar report on Yagis). The procedures they used represent good
engineering practice (I once ran antenna test ranges in the aerospace
business). The AV620 and R6000 were not reviewed, but the R-8 was
and appeared to be the best overall choice from 40-16 meters (the
R6000 is quite similar for 20-6 meters).
Looking at the descriptions of the Hy-Gain verticals, the AV-620 is
very much like the R-6000 except for using loading coils/capacity
hats instead of traps. The AV-640 and R-8 are similar in the same
manner. The Hy-Gain verticals are significantly less expensive than
the Cushcraft equivalents, however.
I purchased and installed an AV-640 in late 2001 and have been quite
pleased with the performance on all bands using both QRP and QRO rigs
for casual operating, DX and contesting (I have worked nearly 200
countries overall and about 100 QRP with this antenna, plus all but a
few states). My vertical is mounted on a pipe attached to the side
of my house, about 15 feet above ground and approx. 250 feet from sea
water, which undoubtedly helps. The tuner in my K2 easily matches it
across the entire band for each of the 40-10 meter ham bands. I have
even loaded it up on 80 and 160 (100 W or less--I wouldn't try much
more) and made contacts of over 1000 miles during contests.
73 - Bob, N7XY
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