[AMPS] Hot Switching

[Dick Green]

> That's a good point, Dick - did you measure the 7ms delay in the FT-990
> using the transistor remote switching option, or the relay option?

I measured the timing of the transistor remote switching option. I didn't
see any provision in the 990 schematic for keying the amp on key closure
when the relay option is selected -- basically the switch just transfers the
signal from the transistor to the relay. So, I have to assume there's a 7ms
delay for the relay, too. I didn't think it was worth testing because the
relay isn't rated for QSK and it's noisy, so there was no way I wanted to
use it.

> Another possibility for the 990 might be to route the key closure
> directly from the key jack to the rear ACC socket. A couple of steering
> diodes should ensure that the amp gets the PTT signal in real time,
> while the 990 can still hold the PTT line down for a few extra ms on un-
> key.

Not a bad idea for QSK, but it won't work in VOX mode (don't want to key the
amp for every element in that case.) In VOX we  need a signal that does what
PTT is supposed to do -- switch on when the key closes and stay on until the
end of the VOX delay time. I haven't yet dug through the tech manual to see
if there is such a beast.

73, Dick WC1M


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