[HomeBrew] Transmitter design concerns/help

[kwylow zinjanthropus]

All:

I'm currently building a CW (AM capable with modulator) 2 tube transmitter that I'd like to have generate 50-60 watts between 160-10 meters. Just wanted to know if the following is possible or should I know about any particular problems:

Design is based partly on WA6VVL's dual 1625 xmtr with a 6AG7 osc. Instead of the 1625's, I'm opting for a single 6146. Most of the tank circuit parts came from a Bendix Marine transmitter that originally used a 6146 variant and produced 90 watts out. Tank coil is 1.75" in diamter, 2.75" long at 15 tpi. Plate cap is a variable Cardwell at about 350 pf and the load cap will be a triple 500 pf broadcast type unit. Bandswitch will be a 6 position BC-375 unit acquired from Fair Radio a few years back. The driver circuit will be an xtal/VFO switchable 6AG7 unit. Here are my questions. 

-I have a 600 VCT, 250 mA xfmr I also bought a few years back from Antique ES. Can I full wave bridge the secondary to produce 600 VDC while I bring out the center tap to a cap/inductor circuit to provide 300 VDC for the lower voltage circuits? I suspect that between the amp and the osc/driver, I shouldn't be "railing" the power supply's 250 mA capability. Sounds ok? 

-Position of the coil. I'm trying real hard to keep the bandswitch as close to the tank coil as possible. I think I can get it within 3" at the farthers point with the nearest point having the coil and the switch almost touching each other. Any problems here? 

-6AG7 circuits should be shielded/enclosed from causing any interaction with the PA circuits. Am I correct in this assumption? 

-The 1962 ARRL handbook shows the 6146 with a 10 pf feedback cap for neutralization. How necessary is this circuit (as I haven't seen EFJ Rangers or some other transmitters with a neuralization circuit)? Let me know on this!

-Will I have enough "juice" from this transmitter to add on an additional outboard p-p 6L6 driven by a 6SN7/6SL7 plate modulation set up? 

Let me know and thanks. Any other questions not addressed, please let me know. Cal, N6KYR.



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