[Elecraft] KPA1500 SWR meter

[Bud Semon]

I have the same problem with S/N 64.  I thought it might be a cable but the
problem occurs on all bands, both antenna outputs and into a dummy load.
I'm only about 90% sure that it is related to temperature - I was too busy
working the contest to do much more troubleshooting.  And I agree with the
fan noise comments - the pitch of the noise comes right through my Bose
noise canceling headphones.

73, Bud  N7CW

On Sun, May 6, 2018 at 3:43 PM Don Butler <n5lz at comcast.net> wrote:

> Mike I had the very same thing happen last night while operating the 7QP
> contest..... which is the first contest I have operated with the KPA1500
> .... the heatsink temperature was down in the mid 40s C at the time ....
> and
> in my case it occurred on 160 meters only .... SWR as per other meters as
> well as the digital readout on the 1500 were reading 1.2:1 ... and did not
> change even when the LED flashing occurred ..... but I was getting
> intermittent flashing of all LEDs on the amp's SWR meter ....
>
> During the contest I was continuously running on CW with hourly QSO rates
> running between the 70s and 110s .... I opted to manually switch on the fan
> to keep the temperature below 60 degs C ..... level 2 seemed to keep it
> there most of the time .... but I did move up to level 3 a few times  (and
> BTW, at that speed the KPA1500 is clearly the noisiest amp I have ever
> owned
> .... but, arguably, it may very well be the "coolest" also ..... headphones
> were absolutely necessary with that noisy fan ..... clearly much noisier
> than the Alpha 9500 sitting right next door ... which I also used during
> the
> same contest...
>
> So Mike, you're not the only one experiencing this phenomenon.... whatever
> it is..
>
> Don, N5LZ   (KPA1500 #45)
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Mike Crownover
> Sent: Sunday, April 29, 2018 8:13 AM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] KPA1500 SWR meter
>
> I have noticed that after my KPA1500 gets above 50C the SWR indicator light
> starts to show intermittent high SWR. My KPA500 did not do that. I'm using
> resonant yagis and the digital SWR meter shows 1.1:1 and doesn't change nor
> does the SWR indicator on the K3S. It seems the SWR indicator lights are
> acting independent of the meter on the KPA1500 screen. RF? I have not had
> any faults or shut downs as a result of the indicated high SWR. The amp
> operates wonderfully, but the indicator lights are a bit bothersome. Anyone
> have similar issues?
> 73,
> Mike AD5A
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