[Amps] new Alpha

Paul Christensen w9ac at arrl.net
Sat Jan 22 09:56:56 EST 2022


>"OM Power uses the Chinese FU728, about a $400 tube but can’t hold a candle to s your Eimac tube."

Seems fine with my OM Power 2000A+ amp that runs 24/7 at my remote site.  The amp is never turned off.  Being a tetrode, the FU728 easily produces 20 dB of gain.  15W in delivers 1500W out all the way through 6m.  Not sure if I'm just lucky but I've been happy with the amp and quality of the FU728 tube.  

The amp does have some issues that are addressed on my QRZ page, all of which are manageable by the end-user.  For example, when using QSK, approximately 10% of the keyed CW elements result in hot-switching the input T/R relay.  The root cause appears to be a periodic interrupt in the microcontroller code.  I solved the problem with an optocoupler.  The optocoupler senses the input key line and forces the input relay to close when in operate mode.   Problem solved. 

Paul, W9AC 




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