I think this is a lot of worry about normal behavior.
Although it's not directly discussed, some insight might be gleaned by reading through this old thread:
http://elecraft.365791.n2.nabble.com/K3-SWR-Numerical-Indication-td7643839.html Wes N7WS On 4/10/2020 6:59 AM, Lyn Norstad wrote:
At 100w on 20m, my KAT500 Utility shows an SWR of 1.00 with the KPA500 on Standby and temp around 38ºC. But as I switch the KPA to Operate and increase the power to 300w the SWR goes up as high as 1.10. If I hold it there (key down) long enough the KPA temp starts rising slowly. At about 50ºC I can hear the fan picking up speed. By the time I get to 60ºC the fan is at probably level 2 or 3. SWR is still at 1.10 (max). Right or wrong, I've always assumed there is some slight heating in the antenna system (Tuner, Balun, Lightning protection) although all components after the tuner are rated at 5 KW. 73 Lyn, WØLEN -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Alan - G4GNX Sent: Friday, April 10, 2020 6:27 AM To: Elecraft Reflector Subject: [Elecraft] KPA 500 I have a strange fault a couple of times recently, where the SWR starts to increase during the time of a single 'over'. I've been using the K3S set at 100W out, via the KPA500 (in standby) and the KAT500 tuner, without any problem, but after I've switched the linear to Operate and driving it to 200W, the SWR creeps up. I don't think it's an antenna issue, but a possible heat problem with the KPA500. I watched the temperature display on the KPA500 and initially on Standby it shows about 38 degrees C. After transmitting at 200W the temperature slowly rises above 60 degrees C, but the fan doesn't cut in. Does anyone know if this is normal behavior and what temperatures I should expect to see? I have tested the fan via the Menu function and it works as expected. 73, Alan. G4GNX
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