The following tests wer performed today. I am looking for any
feedback...critiques on the methods.
Freq: 1830KHz
TX: TS940 at about 10W thru a 10dB Bird attenuator to minimize any VSWR
problems.
Feedline: 300' of 3/4" CATV hardline
TX monitor: OHR QRP Wattmeter reading 1W fullscale at all times.
RX Site: about 7 miles away at about 200' lower elevation
RX: Old Navy RBB-5
RX antenna: 60' vertical wire and 2 130' radials plus a 8' ground rod
Test Equipment: AIL Model 30 tuneable attenuator, resettable to within
.2dB. Ballantine Model 300 true RMS Voltmeter.
Coordination: Commercial 460MHz HT's thru my repeater. The other site is
a 2 way repair business owned by an old Navy buddy of 30+ years.
The test antenna is a full size 1/4 wave #12 wire vertical hung from the
top guy of a 180' tower. The antenna slopes out to about 65' from the
tower.
The second vertical was completely removed so as to not confuse any
readings.
Started with the original 6 elevated radials which start at 8' above the
ground, then go up at a 45 degree angle to about 20' above ground and
then supported at roughly that height on tree branches.
Set the reference at the above point.
Six new 150' radials on the ground.
Connected the six new radials while still on the ground.....results NIL.
Connected the six new radials at the same heights as the
others...results...about + 1dB maximum.
Retested with the original six radials but the other six still elevated
and not connected. Resuits....no measurable change from when on the
ground. Suspect the non-resonant length made them "invisible" when just
floating.
Finally I ran a pair of #12 wires from the base of the test antenna to
the base of the second antenna ( remember...no radiating element) with
its own six elevated radials....no other interconnecting wires.
Results...a solid + 2dB even though the new radial field is behind the
antennas view to the test site.
Conclusions: none yet, based on input I can either rerun these tests or
proceed to another test site with a real 160M antenna.
73 Carl KM1H
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