Rich said:
>However, PIN diodes are a whole nuther ballgame.
My thoughts, too. I discussed this sometime back with George, W2VJN, and he had
his reservations.
>However, the NPN transistor will not key a negative-V.
Depending on the volts you are switching, an opto isolator can be a convenient
level shift/isolation device to go with a high voltage PNP/NPN transistor to
switch negative voltages.
>The good news about vacuum relays is they recover reliably from static
discharges.
I figure that as a good reason for tube PA stages. I arrange the antenna
changeover to be energise for receive. This connects the antenna to the
amplifier when the station is switched off, on the basis that a tube rated for
several thousand volts of swing has a better chance of sithstanding things than
a solid state front end - and probably with a tuning cap or two going to arc
first anyway. Not that we have lightning at all comparable with that which you
get in the US.
73
Peter G3RZP
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