Sequencing for preamps etc

Steve Bunting

Hi everyone,

I have a 6500 that I use for VHF work, driving an transverter, Amp, and Mast head Preamp (MHP). I have managed to pop my MHP (again) which has made me think again about how this is all sequenced. This worked fine without an amp, but blew first time that I added the amp to the system.

At the moment I have the TX delay set to 100mS. TX1 (disengage MHP) at 10mS, TX 2 (Tvtr tx) at 30mS and TX3 (Amp tx) at 50ms. There is a 300mS delay in WSJT and same in PTT control in N1MM. Does that look sensible? I have made the numbers big on purpose to make everything safe supposedly!

I see that KM0T posted here a few years ago using a denkovi usb relay board to do external sequencing. What are the advantages of that comparted to using TX1-3?

Thanks

Steve, M0BPQ

Mike-VA3MW

Have you confirmed that TX RF is what is blowing the preamp or could it be some other cause?

The delays in TX1, TX2 and TX3 all run in parallel, meaning they all start at the same time.

The TXD or TX Delay timer starts at the conclusion of the longest running of TX1, 2 or 3.

The way to test this is to set the timers to some long values, such as 1000ms and with those long times, you can actually watch what is happening.

Mike-VA3MW

Here is a 'draft' diagram on how it works thanks to Dan N7HQ

KD0RC

Excellent diagram Mike. Dan does good work! I would like to see this in the hardware manual when it is revised.

Dan-N7HQ

Thanks for the compliment, Len. That diagram is included in the 8000-Series Hardware Manual - look for that on our website very soon.

73 and Happy Thanksgiving,
Dan, N7HQ

KD0RC

Very cool, thanks!

Dan-N7HQ

The 8000-Series Hardware Reference Manual is now available for download on our website.

Here is a link: FLEX-8000 Series Hardware Reference Manual

73,
Dan, N7HQ

Steve Bunting

Thanks. I had assumed that the TX delay timer overlapped with TXs 1-3, which makes my timing sequence even more conservative. I will get the preamp off the tower and replace the active device and try again……

Thanks

Steve, M0BPQ

W2PP

if you need a reliable sequencer check out the SSB Electronics one. I use it here. Gets the job done well

Petet