I have used this approach many times for transverters and amplifiers. . . The
PTT goes through the radio and out to the switched element which then keys the
transmitter on a return pair to the radio PTT. I have not used this approach
on QSK so can't relate observations there. However, no pre amps have been
toasted nor amps improperly driven at normal VOX or transmission period keyed
CW.
BTW. . .Ian. . just ordered one of your triode boards from DEM. 'going to
install it in a 3cx1000a7 6m amp. . .
73
Art
"Ian White, G3SEK" wrote:
> >>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.
> >
> >Delaying relay break could cause a problem. Relays need to open quickly,
> >as well as close quickly (contact bounce time included). If the relays
> >do not open blazingly fast, the next burst of RF could arrive when the
> >contacts are bouncing.
>
> All transceivers have some break delay, in order to avoid hot-switching
> their own internal TX/RX systems. My suggestion would not affect the
> existing break timing - it would only speed up the make signal getting
> to the amp.
>
> 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
> 'In Practice' columnist for RadCom (RSGB)
> http://www.ifwtech.com/g3sek
>
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