I got about a dozen replies. Here are the pertinent ones:
1) If it is like most Icom's, there is a loop in the receive line between
the T/R switch and the RX input on the radio. Simply remove the jumper
and get either a 2 - 3 - or 5 position cable tv antenna switchbox from
Radio Shack and put inline. You can then add several other receive
antennas to be switched. One secret hint -- the 5 position switch can
combine 2 or more RX antenna sources to one output!
Works great! I use the phono plugs for the RF cables and use F to Phono
adapters. This way it is easy to use RG8-X for the junpers. (OR RG58 -
ugggh!!)
**My comment. I did that with my IC-735 but the IC-746 doesn't have the
loop in the receiving line. I was hoping someone had gone inside the case
and found a neat way to do this on the IC-746.
from #1 a PS) Also, I put an ICE RX overload protector in the switch output
line.
2) I use the PTT line for keying the 12 volt dc relays. There are a
number of relays in use - some for selecting antennas, some for selecting
directions (on lazy v antennas) and some for selecting the EWE rx antennas or
directions.
** For those who misunderstood my question, I know how to switch the EWEs.
The method I use is a manual switch inside the shack. What I was looking
for was insight into whether or not ICOM had a loop in the receive line
between the receiver and the TR switch.
** And for those who asked about the IC-746, my 160m and 80m antennas are
down. I had to take out a dead tree and it fell accoss where the radials
were. The 160m elevated inv L and 1/4 wave elevated 80m vertical will be up
for the fall season. I hope to get on 10, 15, and 20 for the IARU contest
this weekend and try out the rig then.
73 Ed
K3IXD
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