Separating the Tx and Rx lines on 2 meters in the IC746 could not
Put the rig on the bench with the front panel facing towards you, and
turn upside down, with the front panel still facing towards you.
Remove the bottom cover.
At back-left there is a 5 inch square metal screening plate held in
place by four screws - remove it.
You will see a miniature co-ax plug and cocked, labeled VRX.
unplug, tuck the original plug out of the way and plug in a new plug
attached to a length of miniature coax, which can neatly leave the rig
through the hole on the back panel that contains an earth bolt. Now
you have your separate receive input!
You could cut off and re-use the miniature co-ax plug, but I preferred
to contact my local Icom dealer and buy a new one (a couple of
dollars) - the Icom description is: PLUG TMP-P01X-A1 (Min Coax)
Icom 746 2m RX and TX separation mod.
For most of us weak signal enthusiast we run mast mount preamps at the antennas. The problem is switching the preamp out of the TX line. This can be done with two coax relays at the antennas, but to keep losses down one relay is used at the antenna and two feed lines are used, one for TX and one for RX but this requires another relay in the shack adding more loss and costs. An easy solution is the modify the rig with separate RX and TX connections therefore eliminating the in shack relay. This is also eliminates the need for relays in or behind your amp.
This mod was posted on moon-net by G4YTL. I have not tried the mod yet but will be doing so soon. If you have done the mod already pse let me know your results and I will post them here. _________________________________________________________________