If you’re using a BALUN is it saturating or ha anything changed in your antenna system? Connectors checked for tightness?
Sent from my iPhone ...nr4c. bill > On Dec 19, 2018, at 2:13 PM, Bob McGraw K4TAX <[email protected]> wrote: > > I just performed a transmit test on 10M with my radio. CW mode, key closed, > 100 watts into dummy load, PA current 17.38A as indicated on the radio, PA > voltage 13.6 volts as indicated on the radio. After a 2 minute key closed > period the PA temp was 56 C and stable. Fans stepped to max. > > Same test on 80M. PA current 18.3A , PA voltage 13.5V and PA settled at 57 > C. Fans stepped to max. > > Also ran 10M RTTY / AFSK at 100 watts out with a 1 minute transmission and > observed about the same as above. > > The 15 second transmit / receive cycle sounds like WSJT-X and FT-8 mode or > MSK-144 mode {not normally used on 10M} Normally I do not run any analog > digital mode at 100 watts due to a bit of compression that appears to occur > in the PA stage. My suggestion, as I do, run 50 to 75 watts with analog > data. Likewise with the KPA500, about 300 to 400 watts max for analog data > signals. > > In working SSB do you get reports of "fuzzy audio" or with PSK-31 get reports > of poor IMD ? If so I would suspect an issue with the KPA3A. Consult > Elecraft Tech Support. > > 73 > > Bob, K4TAX > > >> On 12/19/2018 10:34 AM, Robert Harvey wrote: >> Hi Bob and Don: >> >> Actually, I am not transmitting data at anywhere near that length of time. >> I am talking about a 10-15 second transmission in which I notice this. >> >> Just some observations: >> >> 1. There is no cooling fan obstruction and they run normally as far as I've >> been able to observe. >> 2. This is a new problem. >> 3. The power supply is delivering 14.0 volts under load, with a line drop >> of .2 volts on transmit. >> 4. This occurs into a dummy load, or any one of three matched antennas. >> Even bypassing tuners into the DL or antennas shows this same effect. >> 5. The antenna system SWR is steady, both on the DL and on the antenna's >> while this is taking place. >> >> If this is more or less normal behavior on 10M, and not indicative of >> bandpass filter failure or imminent failure, I can live with it. I can run >> the KPA500, which only requires about 20W input on 10M to get full output, >> so I am not concerned about loss of signal all that much. >> >> Thanks and 73! >> >> Harv >> K2PI >> >> >> -----Original Message----- >> From: Bob McGraw K4TAX [mailto:[email protected]] >> Sent: Wednesday, December 19, 2018 1 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
