[Elecraft] K2 current draw

[Robert Tellefsen]

Vic
The bandpass filter alignment merely assures you have adequate drive to the
PA.
The LPF will have more effect on the PA current, as it determines whether
you have
a match between the load the and PA.
73, Bob N6WG

-----Original Message-----
From: elecraft-bounces+n6wg=comcast.net at mailman.qth.net
[mailto:elecraft-bounces+n6wg=comcast.net at mailman.qth.net]On Behalf Of
Vic Rosenthal
Sent: Sunday, May 15, 2005 3:39 PM
To: Elecraft Reflector
Cc: Gary Surrency
Subject: [Elecraft] K2 current draw


I just noticed an interesting thing about my K2/100:  the current drawn by
the
low-power part of the K2 (that's the current measured when you tap DISPLAY)
is
extra high on one band: 20 meters.  When I'm running 100 watts out, the
current
displayed varies from about 2.2-2.8 amps on all bands other than 20.  On 20,
it's 3.5 amps.

My first thought was that the bandpass filter was misaligned on 20.  Sure
enough, after adjusting L7 and L8 on 30 meters, the 20-meter trimmers were
at
minimum capacity when the output peaked.  I had to add an 8 pf capacitor
across
one of them and a 27 pf capacitor (!) across the other in order to have the
peak
fall in the adjustment range of the trimmer.  Very suspicious.

After doing this, I verified that the current draw when running 10 watts on
20
meters was in line with the other bands.  But when running 100 watts, I
still
get 3.5 amps!

Something funny is going on.  Why was I unable to get a peak on 20 without
extra
capacity across the bandpass filter trimmers?  And why is the current drawn
at
10 watts normal, but high at 100 watts?

This is not something new, I've just ignored it until now!

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

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