If something goes wrong in the RX antenna switch, you don't have to
worry about the rig transmitting into its own receiver. That can't
happen. The only thing that can happen is that you could damage the
antenna or its preamp. The reed relay is just like the one in your
radio, so it shouldn't be unreliable. I've never heard of one of
those failing.
Reed relays, and on rare occasions other relays or relay systems, come in
two variations.
Some use a single contact bar that moves between NO and NC positions. These
are OK, because they can never do two connections at once if something
fails. The contact carrier is either one way or the other. These are
potentially good as transfer relays.
Some use dual reeds or dual contact carriers that are mechanically
independent. If something goes wrong, they can make two connections at the
same time. They also can have sequence issues where they make two
connections at once. Some vacuum reed relays have two glass tubes inside the
coil with independent NC and NO reeds. These relays are questionable for
anything. They can lock in two contact positions at once, tying all three
terminals of a DPST together. As a matter of fact, they actually do this for
a millisecond or so when transferring. These are bad relays for many
applications.
By the way, some popular radios transmit RF even after telling the external
relay line to release, and some transmit at the very same time as they tell
an external relay to transfer. Most radios are good, but not all radios are
good at timing. Some hot switch on the leading edge, and some on the tailing
edge.
73 Tom
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Topband reflector - topband@contesting.com
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