Re: [Elecraft] TX Calibration fails on 30m only THANKS TO TAX !!!

[Jim Brown]

On 4/7/2020 12:43 PM, Bill Steffey NY9H wrote:

Bob prompted what was my next step ..one short jumper to the load..


Expeditioners that do lots of portable setups have repeatedly preached 
that when anything goes wrong in a radio system to ALWAYS suspect a bad 
piece of coax, and usually a bad or poorly installed connector.


Back in the days when I was doing lots of live recording and sound 
reinforcement gigs, it was mic cables. A standard test was to plug a mic 
into the mixer with the cable(s) to test, listen on headphones with the 
gain up, and "rattle" both ends and the cable itself to expose any 
faults. To test coax cables, I'd do something equivalent with low power 
into a dummy load and watching SWR at the rig.


73, Jim K9YC
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Re: [Elecraft] TX Calibration fails on 30m only THANKS TO TAX !!!

[Bill Steffey NY9H]

yepper the radio is fine...  something between the k3  and the waters 
dummyload/wattmeter  did NOT like 10 mHz.


Bob prompted what was my next step ..one short jumper to the load...BINGO

Now I need to find just where that lump of something is hiding . I was 
fooled in that it calibrated up to 10mHz and manually looked good on all 
the other bands...


thanks Bob for precipitating me to do the right thing.

bill ny9h


On 4/7/2020 2:01 PM, Bob McGraw K4TAX wrote:

I’ve found that one should use a 12” to 18” jumper of known good condition and 
quality.  Use this jumper to connect the dummy load direct to the radio. No 
switches, and no tuners in bypass mode.

The dummy load should be 50 ohms +/- 5 (thats 10%)  ohms and be resistive.  
Light bulbs and soldered up resistors and the like,  aren’t resistive, meaning 
no reactance.   Don’t take what’s written on the label as fact!  They change!  
Measure them with an ohm meter and antenna bridge at several points from 1.8 
MHz to 54 MHz.  Anything greater than 1.1 to 1 is out of tolerance.

Run TX Gain cal on all bands.  Your results are only as accurate as your 
procedure and test equipment.

Bob, K4TAX


Sent from my iPhone


On Apr 7, 2020, at 10:59 AM, Bill Steffey NY9H  wrote:

thought it good day to do a tx calibration.

I don't very often use 30 meters..and today the calib quits at 30 meters 
saying  too high for calibration   4.1 swr...

All other bands indicate swr of 1.1 //  except 10mHz...


I looked and the 10mHz low pass filter is shared with 14mHZ... and 20 looks ok. Don't 
know if the problem is in the tuner while in "BYPASS " for the test, or 
elsewhere.   Any help ???  searching found nothing for me.


bill



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