Howdy, TowerTalkians --
Just finished installing a new C-31XR for Jon, K7ZA, and thought I'd
give a couple of impressions.
The antenna mechanically is typical Force 12 which is to say excellent.
There is a plexiglass piece with holes in it that is used for tying the 2
driven elements together. These elements are very close and any wind motion
causes element movement and gyrations in SWR so these pieces add some rigidity
to the driven elements. The piece with the hoseclamps is a little funky but
works FB.
The SWR leaves something to be desired. Jon is a CW operator so as long
as it looks good on CW, he's satisfied. Unfortunately I think the 15M driven
element is too long as it seems to resonate around 20.500 mHz. The 15M CW SWR
is acceptable but it renders the SSB SWR unacceptable. We decided to live with
it.
This antenna can NOT be tuned on the tower - it needs 100 feet of
feedline per the manual to make the curves look good. The antenna was mounted
about six feet below a CC A3WS and twelve feet below a F12 40M dipole.
The published F12 gain figures corollate with our tribander test report
results so I have a high level of confidence in N6BT's figures. The published
gain figures are impressive - I predict that this antenna will the one to
beat.
Jon's first contact was a DX station that gave him an unsolicited "great
sig" report - this was with 100W. Jon has a very nice 'one tower station' with
the above configuration. He's got slopers on 80M so he's got all bands covered
from 80 to 10M with a 160 inverted L planned.
Cheers, Steve K7LXC
Champion Radio Products
Tower Tech
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