To make this all simpler I normally run the transverter as the LAST box to be
sent to transmit (ensuring that RF switching is disabled!). So
Rig->sequencer->Tx relay->PA bias->transverter. This may hot switch the
transverter, but that's rarely a problem in reality with the low powers and
enables the system to be built with all the normal VOX / Semi-break in
facilities on the radio working normally.
Now just need to find out why some of the Amphenol N-type relays used for high
power switching have got into a state that can take up to 0.5 second to release
after volts have gone. Maybe they've got magnetised - they were originally 115V
AC relays re-wound for 28V DC, but one has already bitten the dust from the
consequent hot switching where the sequencer didn't figure on needing to take 1
second to changeover!
73,
Andy, G4PIQ
-----------------------------------
Brian Alsop wrote :
I guess I'm missing the boat on this discussion.
I thought all high power VHF ops used an external sequencer board that
did the following type of thing.
RX to xmit:
1) Bypass the mast mounted preamp, wait a bit
2) Put the amp in the tx mode, wait a bit
3) Put the xvtr in the tx mode, wait a bit
4) inhibit the RF output from the rig until 1-3 are complete.
With a relay based system 1-3 could easily be 60ms or more.
Going to receive does a similar thing --i.e. unkeying the various
components with delays..
You're not going to get his set of multiple delays from the K3.
There are external sequencer boards available as kits for about $20.
The K3 has an inhibit line for such use.
And yes, the big guns do have difficulty in the bang-bang contest
mode. You call them once and occasionally get the comment, I'm not
getting your call, my sequencing hasn't completed.
73 de Brian/K3KO
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