|[AMRadio] In Defence of Old Buzzard Transmissions|
k4kyv at charter.net
Mon Oct 12 17:37:51 EDT 2015
> I spent an entire day a few years ago experimenting with relays to come up with a method that would best isolate the rx on transmit and
protect the input coil. The way I do it now is almost too good
because I can't hear the 122 VFO for spotting on the CW rig. On the
3-400 rig I spot with both the vfo and driver
I picked up a shoe box full of little coaxial relays at Dayton one year. They work exactly like miniature Dow Keys, but have 24 vdc coils and use BNC connectors. I use them to select which transmitter the VFO feeds to, and with the receiver, to select what feeds into the antenna terminal. On receive it selects whatever receiving antenna I have selected with a rotary switch. On transmit, it completely disconnects the antenna input terminal from anything else and, to boot, grounds it. I can hear my VFO well enough for spotting, but sometimes I have to switch to a different receiving antenna to get enough signal. I have a separate spotting switch, so I don't have to switch to transmit to hear the VFO.
Lately I have been using my 3885 kc crystal for 75 while keeping the VFO connected to the Gates for 160.
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