[Elecraft] KPA 500

[Randy Farmer]

If the initial VSWR is really measuring 1.00:1 with low power, that 
means the detected reflected power is exceptionally low. I'm sure the 
algorithm used to compute SWR sets it to 1:1 if there's zero reflected 
power. If the load is not really perfectly flat, as the incident power 
is increased the detector will finally see enough reflected energy to 
give an indication. You have absolutely nothing to worry about in your 
system.

73...
Randy, W8FN


On 4/10/2020 9:59 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