[Elecraft] k3 High Current Message on 10 meters

[Nr4c]

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 <rmcgraw at blomand.net> 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:rmcgraw at blomand.net]
>> Sent: Wednesday, December 19, 2018 1