Dear contesting OM, personally I am always SO and never even tried SO2R. In
‘80’s and ‘90’s, I had operated from MM / Multi-2 and I thought I understand
the setup rules.
In last few years in Club FD and WFD operation, we are expanding from 2 ~ 3 ~ 4
radios. Now the high band opening cannot be expected, so the operation stays
in 80, 40 and 20 most of the time.
Typically the radios are Flex 6600, TS-590, FT-950, TS-440 (and IC7300), all in
100W and old analog to SDR combination. No key click or audio distortion
issue. IC7300 is indicating ‘OVF’ without P.AMP so obviously over loaded.
Antennas are in the wide range of 40~10 multiband Yagi at 110’, 75/40 inverted
vee (2 antennas placed in N/S and E/W probably 20’ apart), 2 separate 40 and 20
¼ wave full size ground mounted verticals, 80-10 base loaded ground mounted
vertical … Antennas have balun, current choke, LMR400 or RG213 cables, Array
Solutions band-pass filters …
Type of the interference is not the single signal 2nd harmonic. Typically when
80 is on TX, the RX on 40 is interfered with S5-9 noise in almost entire band
up and down – desense by fundamental or 2nd harmonics ? Some in the backward
by ½ harmonics ? is also happening. RX does not use NB. ATT reduce the amount
of interference but the wide band interference does not disappear – cut more
real signals than the interference. Rule allows 2 TX’s in the same band as
long as in the different mode but we are not even close to 2 different bands
simultaneously.
Radios are at least 10 ~ 30’ apart, not grounded. What could be the next step
should I take ? Running 6 full regal power TX’s in 160 – 10 in the MM
environment is beyond the imagination. Ground Cu plate under each radio ?
More current choke ? Antenna separation in 100’s of feet ? (How do you do if
you have different band antennas on the same tower ?)
Your expert advice will be very much appreciated. 73 de Jon NN5T
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