Date: Thu, 11 Mar 2010 09:01:17 -0500
From: "Rex Lint" <rex@lint.mv.com>
Subject: Re: [Amps] Amps] Solenoid polarity on DC reed relays
To: "'Bill VanAlstyne W5WVO'" <w5wvo@cybermesa.net>, <n8cc@mei.net>,
Bill,
I'm doing a similar project with my SB-220, but the HF version. I got the
reed relay from Richard Measures. He also has things to say about snubbing
diodes and resistors. See
"High Speed Switching / QSK for the TL-922 and SB-220..." at
http://www.somis.org/QSK922.html, and his order page at
http://www.somis.org/Price-Info.html. I haven't done the mods yet...
-Rex-
## measures uses a reed relay on the input.. and a transistor for switching
the bias.
## come glitch time, don't be surprised when the bias switching doesn't work.
## the drawback to using a reed relay on the input is.. the amp will not handle
more than 100w
on bypass ! OK to use a reed relay for the bias though.. as long as
contacts are up to the job.
## In my case.. the L4B has a built in wattmeter, and the only way to calibrate
it is to apply 1 kw from
a 2nd amp.. via a calibrated wattmter,.. to the input of the L4B [ with L4B
in bypass mode]
## In bills case.. he's using vac relays on both input and output. Either use
a new reed relay
for the bias.. or a vac relay...esp for qsk
## If the surplus relay in question , is only good for 100 k operations...
and no doubt it's used
it probably does not have a lot of life left in it..esp for qsk use.
Later... Jim VE7RF
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