Hi Gang:
I just finished getting my Force12 C-31XR tri band beam up onto my 70'
Rohn 45G tower. If you own one of these antennas, I would like to hear
from you as to the VSWR measurements you are getting. Especially on 20
and 15 meters. The antenna specs posted on the Force12 web page:
http://www.qth.com/force12/index.htm
Indicate that the VSWR should be no greater than 1.7:1. However, mine
is more that this:
20 Meter Band:
Frequency Pf Pr VSWR
14.000 300 50 2.37 out of spec
14.050 300 45 2.26 out of spec
14.100 300 40 2.15 out of spec
14.150 300 30 1.92 out of spec
14.200 300 20 1.69
14.250 300 20 1.69
14.300 300 20 1.69
14.350 300 20 1.69
15 Meter Band:
Frequency Pf Pr VSWR
21.000 300 30 1.92 out of spec
21.100 300 40 2.15 out of spec
21.200 300 45 2.26 out of spec
21.300 300 50 2.37 out of spec
21.400 300 60 2.61 out of spec
21.450 300 65 2.74 out of spec
I hired a commercial antenna installer to get this antenna up and he has
encouraged me to write to Force12. I have sent both Tom Schiller, N6BT
President and Nathan of Force12 emails concerning this matter. However,
I have yet to hear back from them. I sure did not get this treatment
when I was dealing with them on specs and a sale.
My antenna installer is growing impatient and is pressing me to get on
with the completion of this installation. So I am trying to gather
actual info from other owners who have personal experience in measuring
their C-31XR's results.
My antenna is up by its self and should not experience any other
problems with the environment. The measurements I have done were using
a Bird Watt meter driving the antenna with a Collins S line with 30S-1
linear.
In addition, my antenna installer has gotten the same SWR measurements.
So we are in agreement. All of the suggested methods mentioned in the
instruction manual have been tried by my installer and nothing has
brought my VSWR measurements down to the Force12 specs for the C-31XR!
Thanks John K7JB
--
Best 73's
John, K7JB Amateur Radio Since 1958
Collins Collectors Association MEMBER
QCWA LIFE MEMBER
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