Hello the list,
I disassembled the toroidal transformer in the loop ATU and found the
cores to be good. I will attempt to pick up some teflon insulated wire tomorrow
and rebuild the transformer, if all goes well will be back on the air tomorrow
evening.
--
73 Warren K2ORS/WD2XGJ
FN42hi
http://www.w4dex.com/wd2xgj.htm
-------------- Original message ----------------------
From: [email protected] (Warren K2ORS/WD2XGJ)
Hello the list,
Many thanks for all the reports last night from Hartmut, Jean-Pierre (F5YG),
Juan, Gary, and Roelof (Hope I didn't miss anyone!)
As many of you have noted the signal dropped off at 03:00 UTC. At 04:00 I
noticed XGJ was very weak on the W3EEE 'grabber'. I went downstairs to the radio
shack to investigate. The antenna current (measured at 50 ohms) was less than
100 mA ! It should be approximately 5 Amps from the Decca PA. I checked the
Decca on a dummy load and it was ok. I tried the smaller transmitter and noticed
a very high SWR. I went out and looked at the ATU, flashlight in hand. The
secondary of the toroidal step down transformer had arced and burned through the
insulation. I believe that the very high humidity played a part in the breakdown
of the insulation. I will have a look at the transformer today and may be able
to repair it if the toroidal core is not damaged. I am hopeful that the core is
o.k. since impedance measurements showed no change and I was able to run the 250
watt transmitter into the antenna with a low swr after a period of time (after
the tuner cooled down).
I will of course use better insulated wire for the high voltage!
--
73 Warren K2ORS/WD2XGJ
FN42hi
http://www.w4dex.com/wd2xgj.htm
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