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QCX+ 3.98 Watts to 7.5 Watts...Here is what I did...


Shane Justice
 

Brian,

That's some great twerking there! I'm still sorting through my no audio issue. Spent the last hour or so going through the complete IQ chain, all the way through the audio chain. Ugh! My back is aching from being stooped over the bench for the last five hours..

Congrats on your success!

Shane


On Oct 17, 2020 at 19:40, Brian N7BKV <cl@...> wrote:

I have been running my QCX+ for a couple of weeks now.  Initially the onboard power meter (Menu 9.2 RF Power) indicated 3.98 watts when I first got the radio powered up on 13.8 volts supply.

So I went back into the radio today and did another alignment procedure several times.  Cleaned up a few things and remeasured  into a dummy load.  This time the onboard watt meter pegged at 5.2 watts (that is all it goes).  I put the MFJ 868 Wattmeter inline and it measured about the same.

So I reviewed Han's video on Tuning Up Your QCX.  It is on the QRP Labs YouTube channel.  Messed with toroids just like he said   Measured performance at each messing.

The net of what I did was this: I spread out L4 windings, L3 stayed the same in the end,  Spread L1 a bit.  And REALLY compressed L2.   There were some not so good tries along the way that proved no good. So I just reversed the effort and tried the next thing.  Your experience will be different.  Measure watts at each step you take.

End result:  6.5 watts !!!!!!  Yippie!!!!  It seems mostly  in the toroids--Twist and Shout!!!!

Watch the vid and document your steps and results.

Once I had that all put to bed I switched from the Samlex 13.8 volt power supply to the Toshiba 15 volt supply.  That is the one I powered my original QCX with, which ran reliably at 7 watts.  This new QCX+ is delivering 7.5 watts into the antenna!!  I am happy.

Hope this helps someone.

Next step is to put the 50W PA on the new 20 volt PS that arrived today.  On 13.8 volts  and all tuned up it was delivering 45 watts. 
More to come!

73
Brian N
N7BKV