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[Amps] HL2K high SWR input

To: "" <>
Subject: [Amps] HL2K high SWR input
From: Patrick EGLOFF <>
Date: Sat, 5 Mar 2016 07:41:21 +0100
List-post: <">>
Hi all,

I have a HL2K amplifier (pair of 3-500Z) for several years now (got it
second hand) and it always had a high input SWR on 21 MHz. I matched it
with my TS850 antenna tuner, so it was OK.

During last contest i had a problem on 40m (500pF/2kV in output tank
shorted). So i had to open the amplifier and while being there i wanted to
see what's wrong with this SWR.

I couldn't reduce the SWR in adjusting the capacitor.

I removed all components used in the input tank and checked them. They are
all perfect.
Coil is 0.34uH and caps are as marked and on diagram.. Input C = 150 pF and
output adjustable up to 200 pF.

So now, i'm stucked....

On all other bands, the input SWR is just fine, so i suppose there is no
problem with the tubes or anything else in the amp. I have full power and
everything is stable.

Does anyone have a HL2K and can confirm that it is OK (or not) on 15m ?

Any idea on what could be wrong ?

73, Patrick

Patrick Egloff - TK5EP
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