On Sat, 17 Oct 1998 19:29:00 -0700 Brian.Harris@sv.sc.philips.com (Brian
Harris) writes:
>
>Sam (et al),
>
>When it was by itself my XM240 I measured the forward and reflected
>power using
>two different Drake W-4 wattmeters. The SWR in the first two columns
>below was
>caculated by the formula (Pf+Pr/Pf-Pr).
Whoops, the formula should be:
SWR = (1+SQRT(REFLECTED/FORWARD))/(1-SQRT(REFLECTED/FORWARD))
The third column was obtained
>by using
>a Mirage SWR meter in the shack. The Drake measurements were at the
>end of 85'
>of new coax but similar readings were measured in the shack through
>another
>100' or so of coax. While I don't believe the actual readings from
>the Drake
>meters, their relative readings seem to show there is little effect on
>my XM240
>by the TH6. The TH6 boom is parallel to the XM240 boom and the TH6 is
>10'
>below the XM240. I split the CW and LOW measurements on the XM240.
>
>
>On the other hand, when installed under the XM240, the TH6's minimum
>SWR point
>on 15 meters (I haven't measured resonance yet) moved downward about
>200 KHz
>from where it was when the TH6 was pointed straight up with the
>reflector about
>20' above the ground. The behavior on 20 and 10 meters was not
>noticeably
>effected. The TH6 was tuned for LO PHONE.
>
>Freq SWR (solo) SWR (w/TH6) SWR (w/TH6 and Mirage SWR
>meter)
>
>7.0 1.17 1.12 1.3
>7.1 1.00 1.04 1.1
>7.2 1.06 1.04 1.2
>7.3 1.30 1.17 1.6
Ok, the first two columns were calculated incorrectly, but the
Mirage column looks suspiciously flat also. I've never seen
a CC 40-2 this broad. I think something is amiss with the meter,
or the coax is bad, or the reflector has fallen off, or
something.
Dave Hachadorian, K6LL
Yuma, AZ
K6LL@juno.com
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