[Elecraft] KPA500 High Reflected Power Fault

[n5ge at n5ge.com]

Sounds to like your LDG Tuner can't match the load...

73,
Tom
Amateur Radio Operator N5GE


On Sun, 15 May 2011 11:00:57 -0400, Nels Anderson <nels at flightsim.com> wrote:

>Been enjoying KPA500 #32 for a couple of days now. Haven't yet made a 
>lot of QSOs with it, but the extra power on RTTY and to bust a couple 
>SSB pile-ups has been welcome.
>
>However, the amp does not like my 40m setup. As soon as I transmit it 
>instantly goes into high reflected power fault and shuts down. My 
>antenna is a 120 foot center fed wire using 1 inch ladder line and an 
>LDG 1 kw auto tuner. SWR on 40m is under 2:1 and the K3 and other rigs 
>I've used it with have always been happy with the antenna arrangement.
>
>In experimenting I used the K3 tune function and reduced the power in 
>steps to see if I could reach a low enough power level that it would 
>operate, but even at 1 watt of drive the amp still instantly went into 
>fault.
>
>On 80m it did the same thing the first time I tried it, but then I 
>manually tweaked the antenna tuner, got a lower SWR reading and then the 
>amp worked. On the higher bands that I've tried there has been no problem.
>
>So, any idea what is causing this?
>
>73 Nels K1UR
>
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