K3 problems during Field Day

[wa9fvp]

If you received this several times, please accept my apologies.  It's been a while since I used
"Nabble" and I had problems up loading the image.


I'm not sure what software N2BJ was using but there was a complaint that the PC
software was doing something to the paddle.

The contest software sends a canned CW message thats stored as text and keys the
 K3 via the straight key input. The CW operator uses the paddle to send other
text.

I'm not sure exactly what was happening, there were 2 conflicting stories, the
operator claimed the paddle speed was changing.

My K3 was running the beta software version 4.51 and dsp 2.76.


My K3 was on 40 meters CW. The 20 meter operator was using a K2. He mentioned
that the K3 was transmitting "birdies" on 20 CW and they thought that it had
something to do with the switching power supply on the K3 that I provided.
They switched power supplies with an analog type but it didn't help.

My K3 is back in the shack and fortunatly I can run some test using another
receiver or a spectrum analyzer to check the spectral purity.

Here are the results;


When I transmit on 7.0644 I can receive a birdie on 14.060. The transmit power
on the K3 is 2 watts into a diapole 400 ohm ladder line and a home brew match
box. The Icom R8500 receiver is connected to my Hygain TH-11 beam. With 100
watts, the birdie is S5.

With a dead carried it sounds more like a buzzer than a birdie. It almost sounds
 like a bad TV antenna amplifier that transmits a drifting birdy on 6 meters but
 this doesn't drift.

[wa9fvp]

I have 20db of attenuation and a spectrum analyzer that can handle 3 watts. At 100 watts and 20 db of attenuation, the spectrum analyzer is receiving 30dbm or 1 watt. The reference level is 40dbm and and the 1st harmonic is 1 division down  from the top.  In this screen shot the 2nd harmonic is about 33db down but I think it should be greater than 45db down from the 1st harmonic.

The 2nd harmonic is at 14.13 but the birdie frequency is 14.060MHz.

[Jim Brown-10]

I was the primary op at K6MI  and worked N2BJ several times. Mostly the
signal was clean, but on one band it was fairly nasty, symptoms sounded
like RF getting into something, think it was Saturday afternoon my time.
Don't remember which band.

BTW -- K6MI was QRP, CW only, with solar power and a K3 on a lovely
5,000 ft peak about 30 miles east of Monterey.  Froze my &*%$ off
overnight, but I was working east coast and W8/W9 on 80M, and was able
to run on 20 and 15 with good rates. Had a BIG tri-bander pointed east,
low inverted Vees for 80 and 40 (but at 5,000 ft, low is relative). :)  
Lost some time due to computer and power problems, so only made about
800 Qs.

My neighbor, W6GJB, had his KX3 set up about 200 ft away and was working
the same bands at the same time into his own tribander using his own
call. We never heard each other, and didn't work, but he did take a
couple of shifts at K6MI.

73, Jim K9YC



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[wa9fvp]

I ran the same test using my Icom IC-7000 as the CW transmitter on 7.065.  No birdies were heard on 14.060.  In both test I was able to copy the 2nd harmonic with an S9 at 10 watts out but there were no birdies across the lower "Charlie Whisky" portion using the Icom 7K.  There was an increase in the noise floor as I tuned towards the 2nd harmonic, starting at 14.120, but below that, the band was clean as a whistle.