[Milsurplus] TBW modulation

[Ray Fantini]

I have been running my TBW for a couple years now on 40 AM (7.29) quite a bit. The external power supply that I put together develops about 1,600 volts on the plate and the internal power supply that I built in the rectifier center section ( and before anyone starts it was gutted when I got it!) provides 400 volts for the B+. I have run the B+ at 450 and the related 500 volts but found that the IA tends to overdrive and produce more spurious products at 500 volts then 400 so I settled with 400, the output power stays the same. I used 1.6Kv because it was the only transformer I had around. with that set up I can easily light a 100 watt bulb in CW mode and a 60 watt in AM, I know its only a couple Db but I use to run a TCS transmitter and no one would hear it and now operating the TBW have no problem being heard. If you do not have the center section the modulation transformer may be a hard item to come up with and you may consider building a external plate modulator then you will have over 100 watts AM. Myself have thought about doing this but being the original modulator was the only thing in tact in the center section when I got it I used it as originally designed and am happy with it, always get lots of comments on the quality of the AM epically when they find out its a sixty plus years old radio and then that its suppressor modulated. Their are pictures of it on my web page at www.ka3ekh.net under project of the week.
Ray Fantini KA3EKH