[Elecraft] K3 with 2m tvtr - power control feature request

[Dave]

Hi Graham

This issue has been pointed out to Elecraft on more than one occasion over
the last few years.   

When using either the internal 2m xverter or the xv output from the back
panel, turning the power knob fully anticlockwise does NOT reduce the output
power to zero like on ALL other bands.  On my K3 setup the power range is 1w
to 9w (144.3MHz). On my K3S setup the range is 1.5-10W(144.3MHz). Both my
internal transverters as supplied were peaked at 147.5MHz , they were
adjusted to peak the output in the UK narrowband allocation(as supplied they
produced 7.5W and 6W respectively at 144.3MHz) 

If using the 28MHz XVerter output from the radio, with the XV level set to
0dBm in the menu,  the range controlled by the power pot is 0dBm to -9dBm on
my K3 and 0dbm to -8dbm on my K3S  If I set the XV level to -10dBm I get
-9dBm at 28MHz irrespective of the power pot setting (ie the power pot does
nothing!)

Rerunning the power calibration routines (on more than one occasion) has
made no difference to the K3 or K3S results

The last response I got from Wayne (sept 2015)  on the issue was that there
is no software solution to the problem;  the suggested "fix" involved
setting TX ALC to OFF

Dave
G4FRE 

From: Graham Kimbell <g3tct at g3tct.co.uk>
To: Elecraft at mailman.qth.net
Subject: [Elecraft] K3 with 2m tvtr - power control feature request
Message-ID: <595E458A.5090409 at g3tct.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I have a K3 (old style) with internal 2m transverter that I want to use 
to drive a  microwave transverter.  There are a few issues with the 
output power -

    * the max output is supposed to be 10W, but measures 7W even after
      calibration - seems wrong but I can cope with thisv
    * the minimum power is 5W but should be down 10dB on the max, ie
      0.7W.  This is a problem because I need about 1W to drive the
      microwave tvtr.
    * the XV config that allows setting the 28MHz input to the tvtr has
      been checked and is exactly the 1mW (0dBm) default.  With the
      power control set to minimum it measured -7dBm.

So it appears that the internal 2m xvtr has too much gain, and there 
does not appear to be any way to reduce the power output below 5W.  Is 
there any chance of making this possible?

I have a friend with a K3S with the same difficulty, so it seems to be a 
common feature.

Graham