On Sun, 13 Jun 2004 00:32:24 -0400, Rob Cherney
wrote:

On Sat, 12 Jun 2004 09:04:51 -0700, Jim Weir wrote:

snip

Just some thoughts, mindya.

A reasonable implementation would receive PTT key signal, wait some
time to let the relays settle, verify that the relay contacts are all
in the correct positions, and then key the appropriate transmitter.
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Robert Cherney e-mail: rcherney(at)comcast(dot)net

If we are going to brain-storm it, let's dump the relays in favor of
SSRs (that can be had in sizes less than a finger nail in real
estate.)

Let's by all means add fifty cents of security with back to back
diodes to limit receiver input excursions to 0.6 volts or less.

Come to think of it, how hard could a functional isolator be?
They've been around for sixty years. But wait: its the bandwidth that
makes those tuned things less practical - great isolation midband, but
skanky at the band-edges.

Brian W