KPA 500 Flex 6400

Scotty

Hello all! I recently received my KPA 500 (KAT 500 still on backorder) I was wondering what delay, if any do you use? Elecraft instruction manual is a little light on flex settings so I am looking for what settings anyone may have, even if it's just a screen shot.

Thanks Scott

N2DZ

Patrick

I used 50ms TX delay, but it is most important to run your keying line to the KAT500 from your XCVR first then to the KPA500. This will protect the amp when antenna tuning is commanded. Or for the KAT500 to hold the amp off until a commanded band change. Set up the amp and the tuner to run off the commands and frequency control via the USB connection. If you need more USB connections a USB hub will work fine to increase connections. Make sure you set up the amps config to intervene to protect the amp if a keying event occurs that would put 100% TX power while amp is keying to transmit. Check amp manual on how to do this. I accidentally killed the diode TR switch and had to have it repaired. Other then that I loved the amp and the really good tuner. Sold them as I needed more power. They had very good resale value.

Scotty

OK I think I have it all setup with the exception of one issue that I am hoping anyone using this amp and flex can help with.

When I change band on smart sdr the amp follows as it should. When I change band on the amp front faceplate the amp changes bands but the radio does not. Am I missing something here?

Craig_KØCF

Nope. That's the way it works. The USB connectors, for the most part, are one-way OUT of the radio. They do not accept incoming commands.

73, Craig KØCF

Craig_KØCF

I had a KPA500 and now have a KPA1500. The amps follow the radio perfectly. I personally don't see any reason to ever have the amp control the frequency/band of the transceiver. Just ignore the band switch buttons on the amplifier and let the radio control it.

73, Craig KØCF

Scotty

He Craig does your amp hum a little when doing ft8/am/fm? Did ft8 a min ago and it humms a little bit just wanna make sure thats normal.

Scott

rbrossetto

I run the same set up. Kpa500. Craig is spot on, one way communication, the amp will not instruct the radio. This is mentioned in the manual. Love this little amp, works well.

Craig_KØCF

I have not worked FT8 in a long time. I think it is normal for a transformer to hum a little under heavy load, and FT8/AM/FM provide that kind of load.

They are great amps, for sure!

73, Craig KØCF