Testing Collins 20 V broadcast transmitter after new final power tubes are installed.  скачать в хорошем качестве

Testing Collins 20 V broadcast transmitter after new final power tubes are installed. 

When you have one of these things you can really say you own a boat anchor. I've owned this beauty for about six years and it's like working on an old vintage auto. I even gave it a name, ie; "Carmen Electra" because of the size of the finals. LOL. It is set up to operate on the 75 meter amateur radio frequencies and is crystal controlled. I've recently come to the realization that the modulation was lacking. Reports came back saying that my audio was very weak. Turns out they were right. After adding a REA modulation monitor that allows me to look at both positive and negative peaks I found that while I was indeed applying 100 percent modulation it was only measured at the negative peaks and I had no idea that my positives were running only 20 percent. The final tube was able to deliver 100 percent carrier but when asked to provide 100 percent positive peaks the tubes poor emission wouldn't allow it. The replacement of the final tube closer to the front fixed the issue. BTW, the glass bulb next to the final tubes is a neutralization capacitor which is necessary when operating at higher short wave frequencies. I have a separate video covering this. You may notice I'm playing a music format into a dummy load which replaces the antenna while I'm burning in the new tube. Boy! Does it sound good through the local receiver.