I looked at the homebrew pair of 4D32 rf deck over the holidays, and since there was room on the deck, and I had a socket and plenty of 4D32's, I installed a 3rd one.
It worked out very well, I now get 300 watts of carrier and 1200 watts pep out, running the rf deck and modulator at 1250 volts. The power supply is good for the power, but a separate power supply for the modulator would be nice, and increase the peak power through better regulation. I also ran the pair of 813's, and had some odd stuff going on, peak power was down, power cord got warm, 15 amp ckt breaker would blow after an old buzzard, and I found the shunt on the plate voltage meter on the power supply was off and reading about 700 volts low, so I was running the 813's at 350ma and about 2800 volts, I think the meter reads more off the higher the voltage, and an indicated 2000 volts is something like 3000 volts! No wonder the power cord got warm! I got to fix the meter on the power supply, but look at the volt meter on the RF deck for now. I also tried out the push pull parallel 100TH mod deck, which happens to be a perfect match to the mod iron at 2250 volts, 10,400 ohms. It took more driving power then the 4x150a mod deck but sounded good.... With 4 100TH plates behind glass glowing orange, I get radiant heat for the shack! I have been looking at balanced antenna tuners, I think I need to build a big one, somehow making a huge coil out of copper tubing. The design in the ARRL handbook uses one B+W 3 inch coil stock with 2 tapped link coils switched in series or parallel, with tuning cap, and the output coils are tapped for each band. I don't want to have to move jumpers and so on, so I like that design, but a 3 inch coil of number 14 is good for 250 watts of AM carrier per the book! How to make a nice coil of the size needed? Brett N2DTS ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
