DATV PAs for 24cms

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radiogareth
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Joined: Wed Jan 06, 2016 9:46 am

DATV PAs for 24cms

Post by radiogareth » Thu Dec 06, 2018 12:25 pm

A while ago (20years!!) I built a PA using one of the then popular bricks M57762 modules. Its on a Bob Platts PCB. As it was intended for ATV I didn't add any ptt in the box, making it a compact and fan cooled unit.
Is it suitable for DATV at reduced drive levels?
Be good to actually use it....
Gareth
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G8GKQ
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Re: DATV PAs for 24cms

Post by G8GKQ » Thu Dec 06, 2018 12:44 pm

Yes. I use one with reduced drive, but it is not very linear, so:
  • Only drive it to 5 watts output
  • Don't use it closer than twice your symbol rate in MHz to the band edges or anything else that you don't want to interfere with
Dave, G8GKQ

radiogareth
Posts: 212
Joined: Wed Jan 06, 2016 9:46 am

Re: DATV PAs for 24cms

Post by radiogareth » Sat Jan 19, 2019 5:15 pm

I remembered that back in 2009 (yikes, a decade has passed) I bought one of John G4BAO's 45 watt PA kits for 23. Having just built his pre-driver amp I dug it out, built it and asked John if it was good on DATV. He recalled an article (since found in CQTV 227 page 35) where it had been reviewed.

Looks like it could be a strong contender, I wonder if anyone else is using one for DATV? Looks like it might out-perform my old brick.....

73

Gareth

g0mjw
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Re: DATV PAs for 24cms

Post by g0mjw » Sat Jan 19, 2019 5:36 pm

I am getting 15W out of my Stealth Microwave 50W amplifier with shoulders 50 dB down. More power than expected. I can get more out, but not cleanly. It takes 15A with no drive rising to 18A at 50W CW, all 12V. It will be needing a blower.

Mike

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