Afterthoughts

Well,

I'm forever adding bits to projects after they are complete. The recent PTT Switching box I made back here is no exception.

Since the original design I've added/changed a few things:

1. I've significantly sped up the sequencer;
2. I've added automatic relay switching for the DRV and RX antenna connections to the TS-990. This means that the transverter RF connections are automatically selected when the band select switch is on 2M or 4M. There's even a delay to the relay activation so that passing the switch through that position doesn't falsely change things over;
3. I've included all the external switching into the schematic as best I can

So there are 4 external PTT connections - these are the triggers to the sequencer and are selected as Radio 1 - Radio 4.

Associated with each Radio PTT input is an ALC output back to the radio so that the selected radio does not generate any RF until the sequencing is complete.

There are PTT outputs to the 3 amplifiers; HF, 2M and 4/6M - these are only keyed when the band switch is in the appropriate place.

There are PTT outputs to both by transverters. Ditto for the amplifiers, these are only keyed when the Band Select is in the appropriate place.

The full schematic is:

and also in a higher res PDF here.

This is our very beautiful Bonnie Dog; in our local dialect her facial expression is translated as "thank God it's spring".

Local conditions.

The PTT Conundrum

Well,

You may remember a while back I described a PTT switching circuit to manage the PTT line to the HF linear, 4/6M combined linear, 4M transverter and 2M transverter and linear. Well, I changed it a little more tonight and added a selection switch so I can drive any amplifier/transverter from any radio. This is the original plan:

I've now broken the line from the TS-990 to the PTT select in the diagram above and added another rotary switch. The complexity is in the need to switch the 4M transverter and the 4/6 amplifier in one setting and just the 4/6 amplifier in another.

The unit looks like this now:

Not the most complex project I've ever tackled, here's the front of the case:

and the back:

and here is the finished article in position:

There's been a few other changes here, I've sold some things and bought some things. Tomorrow my new toy should arrive.... I'll keep you posted.

Local conditions.

Good, egh?