[TowerTalk] Steerable wave antenna question

James C. Hall, M.D. nwtcc at earthlink.net
Wed Oct 20 19:49:32 EDT 2004


Hello:

I have my first Beverage variant - a 2-wire end fed SWA - up going NE - SW.
As per W1WCR's Beverage Antenna Handbook, I have wound and deployed
terminating transformer and receiver end transformer. I'm using 75 ohm RG-6
CATV coax to feed it. Back in the shack, I have an ICE preamp, model 135B,
which is then hooked to the back of my transceiver. So far, I'm just
changing the coax manually to see how it performs. I got a new one on 75M
with a GI0 station using a 80M delta loop on transmit and I was favorably
impressed. My plan is to add a center-fed SWA going essentially orthogonal
to the first one and build the improved null steering circuit as outlined in
the handbook.

The QRN as been quite a problem here in NW TN with the recent storms and I
was unable to hear the TJ station at all on 160M - I did hear him on 80M
however. In switching the two coaxes, I'm having a hard time telling much of
a difference (or preference) in reception. I assume the null steering
circuit is a must for this to occur. Can anybody who has built this circuit
recommend certain parts (Mouser #'s) - I have the FET's and the cores to
wind the baluns - the RS here did not have the recommended POT's, or more
than one DPDT switch ! Is there a reason why one capacitor is listed as 0.1
mfd and another is listed as 0.12 mfd ? Is there any measurements I need to
make outside at the antenna to make sure all is well ? (I have an MFJ SWR
antenna analyzer and a DMM - that's it).

Thanks ! Looking forward to low band activity this winter.

73, Jamie
WB4YDL




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