Thread: A/B Switching
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Old July 22nd 06, 02:54 PM posted to rec.radio.amateur.antenna
Dale Parfitt Dale Parfitt is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 112
Default A/B Switching


"Win" wrote in message
...
On Thu, 20 Jul 2006 12:56:35 GMT, "Dale Parfitt"
wrote:


"Win" wrote in message
. ..
I recently put an A/B switch between my FT-1000 MPV and my IC-746 to
make comparisons between receivers. I would now like to leave this
A/B switch in line, as I would like to use one radio for CW, and the
other for SSB. The IC-746 is known for having a sensitive front end
(easy to damage). I am running 200 watts from the FT-1K. The A/B
switch grounds the unused port. My fear is that the FT-1K will damage
the front end of the IC-746, even as the IC-746 port is grounded.

I have to assume, no matter how diligent I think I will be, at some
point in time, both receivers will be on the same band, near the same
frequency.

Is it probable that the grounded loop to the 746, being 1/8 inch from
200 watts, will survive without damage?

Has anyone operated an IC-746 under these conditions?

Win, W0LZ


My concern would be the port- port isolation of the A/B switch. Depending
on
the mfg, they're all over the map.

Dale W4OP


Dale, the one I have is a XS201, cast iron, much like the MFJ. I
would consider buying a better switch, though, if you could recommend
one.

Win, w0lz



Hi Win,
I have little expereience with the different manufactures of HF switches. My
experience is in relays for 1296 MHz LNA protection- and the port-port
isolation is all over the board.
Ask the manufacturers if they have this spec.
Dale W4OP