Maybe I spoke too soon! This past overnight the transmitter had two cutbacks in power to 75kw from 100kw for relative short periods of time, plus a ‘modulator protect’ alarm. After reviewing this information (plus my observation that the transmitter appeared to be over-modulating) with Joe Barker, the audio input was reduced by 0.1db. For comparison purposes, 1.0db is a barely perceptible drop in level. I also reviewed the transmitter manuals about what causes cutbacks and then tried to find, without success, the parameters that allowed its return to full power. We knew that it did, but why, in some cases, did it recover to full power within a few seconds and in other case it took a few hour?. Since this was not in the manual. I finally ended up calling Nautel, the manufacturer, who emailed this information to us. I thought about putting the information in this blog, but there are 6 different levels of cutback and 6 different recovery times. With this new information, we can now proceed with a clearer perception of what is actually happening.

I spent the afternoon at the transmitter site continuing to troubleshoot the faulty modulation module in the PA module. The manual stated to remove resistor R4 and test six different diodes. When I did this all the diodes appeared bad, so I removed them one at a time, finding each one removed was good but the remaining ones were bad. After all were removed and tested good, it appeared the manual had a misprint and that a different resistor should have been removed to do the diode test! So now I had to reinstall all the good diodes. Next step will be to reinstall the three good power transistors and replace the one bad one.

About 4:40pm, I headed to the office to pick up Virginia at 5pm, but wanted to stop by the house to do a little ‘decorating’, since it is our anniversary. Got to the office on time, barely, but Virginia was feeling lousy with a bad cold and runny nose. She said she did not feel like our usual nightly swim and instead of going out to eat, we picked up some Chinese carry out (sweet-and-sour chicken)and are at home at our ‘decorated’ table. It was very good. We both went to sleep early.