I posted a message on CQ-Contest a few weeks ago about the effects of my
204BA on my 402CD. Esspecially pronouned when the booms were not parallel
with each other. W6QHS (Who's opinion I value highly) suggested that I get
some old TV flyback transformer cores and tape them to the boom of the 204BA
as far from center as possible. ((This option is preferred over buying 2
new antennas of the Cushcraft variety.)) Dave said he wasn't sure if it
would work, but thought it might be worth trying.
Now... I've asked the 2 local TV repair guys that I know in town and neither
had any of these cores available for my scrounging. Does anyone on this
system have such cores that they would like to sell or give me for this
experiment? I would gladly give you credit in the writeup that I do after
the tests.
On this same subject... I decided to model the two antennas. The following
results are from AO with 10 foot spacing between the antennas (The 402CD on
top).
402CD Alone - Frequency = 7.1Mhz - Free Space
Impedance 47.3 + j 7.0 _
SWR 1.17
Forward Gain 3.66 dBi
F/B 7.33 dB
402CD & 204BA with 10' seperation. Frequency = 7.1Mhz - Free Space
Impedance 49.4 + j 30.7 _
SWR 1.84
Forward Gain 2.75 dBi
F/B 3.90 dB
This is fairly close to what I am seeing in real life BTW.
If someone who is good with AO could take my file and rotate the 204 or 402
90 degrees in the model I would appreciate it. I would like to see the
effects with them this way too.
If I don't get the 204BA's detuned for 40M, I'm taking them down and selling
them. I didn't go to all of this work to have my 20M antennas detune my 40M
antennas.
Thanks for your help in advance.
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