[Elecraft] K3/AL-811 questions

[Jim Bennett]

John - 

I've got an AL-811 but this (luckily) has not happened to me. I suggest a call to Ameritron / MFJ, as it sounds like a component in the input circuitry in the amp has gone flakey: able to withstand low amounts of RF but fails under higher power. I had an issue with my AL-811 not being able to load up on 80 meter CW - they were extremely helpful on the phone.

Jim / W6JHB


On Aug 9, 2013, at 8:37 AM, John Shadle wrote:

> Hi all,
> This could be tangentially related to a K3 issue, or maybe K3 experts can
> give some insight here. FYI, when I am not using the amp, I can get 100W
> from my K3 with no problem. Please keep reading...
> 
> I have been using my AL-811 (not new, but new to me) successfully at 500W
> for the past few weeks. Recently (actually, the second time this has
> happened), my fuses both blew and I replaced them. Since I replaced them,
> behavior has not been typical. I can't get anything over 200W (most is in
> the 175W range). I use a tuner after the amp, and I know that the antenna
> is matched quite well to the amp, but my SWR meter on my rig (K3) is
> showing a high value.
> 
> When I tune up at 20-25W I can get about 100W out from the amp. When I move
> to 50-65W I get < 200W. And there is clicking. I can't tell if it's a relay
> or if it's something else.
> 
> So, the main issues are
> 1. High SWR from the rig to the amp (when the antenna is < 2:1 SWR to the
> amp)
> 2. Low power from the amp to the antenna
> 
> Happy to provide other information if folks have ideas on where to look.
> 
> Thanks.
> -john W4PAH
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