Don, Ron, and Bernhard, Thank you for responding. I now have a calibrated KX3. But I'm uncertain if it is sufficient. Nor do I know exactly what has caused the problem. It suspect the problem arose because of the cable or connector from the dummy load to the KX3 was not-quite-right. If you have any other theories I would appreciate hearing them.
Here is what I did. In the original transmit calibration I used an MFJ Model J 280-C dummy load . As suggested, I tested the MFJ dummy load at 52 MHz with an MFJ-269 SWR Analyser. It had an SWR of 1.1 (with R=53 X=3) at 52.0 MHz. While executing the KX3 "Manual Transmit Gain Calibration" the SWR shown at the same frequency was 1.6 at 4.0W. The calibration produced the same error as before. But note that the value of "d" is always a different number. I checked the SWR of the Elecraft DL1 that I built when assembling my K2. It tested at an SWR of 1.1 (with R=54 and X=4.) Running the manual TX calibration the SWR on the KX3 was 1.4. The calibration failed with the same error message as with the MFJ dummy load. Both of the calibrations above were done with an antenna cable purchased from Elecraft. So, I repeated the TX Calibration on the KX3 using a different cable from my spares box. The SWR with both dummy loads was the same but the test passed with the DL1 and not the MFJ. Then I repeated the calibration with other cables. About half of these calibrations done with the the MFJ and the DL1 failed with both dummy loads. However, using two other cables the calibrations with the DL-1 passed but not with the MFJ. Then, with two more cables the MFJ calibration passed and the DL-1 calibration failed. Note that the MFJ has a PK-259 connector and the DL-1 has a BNC connector. Since the cables I used for the calibrations vary as to which connector combination they have I was forced to use adaptors. I suspect the adaptors may not quite be up to snuff. So the calibration succeeds with some combination of cable and DL1 dummy load or MFJ dummy load. Tuck, W6TUK On 09/04/2015 01:14 PM, Don Wilhelm wrote: > Tuck, > > Do you know for sure your dummy load is a good 50 ohm load at 6 > meters? It is always good to check that with an antenna analyzer. > Try repeating the TX Gain Calibration on 52 MHz manually from the menu. > If it completes both 4 and 6 watts without complaint, you are 'good to > go'. > > 73, > Don W3FPR > > On 9/4/2015 11:30 AM, Tuck Watkins wrote: >> The problem is the KX3 TX calibration is failing on 52 MHz at 4.0 W. I >> would appreciate some advice on how to proceed with diagnosis and >> correction. [snip] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
