Mostly depends on what you can get your hands on. These days, you have to design around what you can get at a reasonable price.
As far as tubes go, one or a pair of 813's works VERY well in the RF deck, Pair of 811a or 812a tubes will also do nicely. A 4-125 will work well at 2500 volts. High voltage gets expensive, and the 811/812 tubes work from 1000 volts up to 2000. 813 likes 2000 but works lower. The 4-125, 4-250, and 4-400 tubes like higher voltages. A rice box makes a good RF exciter, and will drive 813's, 812a's, 4-125, etc no problem. For a modulator, KT90 tubes, 811a's, 813,s, 4-xxx will work, The zero bias triodes are easy, no bias, drive the grids with an 8 ohm to 6000 ohm output transformer using some solid state audio amp. Choices are driven by what mod iron you can find, power transformers, chokes, etc. I have a homebrew pair of 813's in pie net 160 to 10 meters Driven by a 4x150 (4cx250b) AB1 mod deck, I have a Push pull pair of 812a's modulated by 811a's, and a pair Of 4D32 tubes in pie net 40 meters only. The old Bill Orr books have lots of good building stuff in them. Brett N2DTS -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, September 28, 2004 3:50 PM To: [email protected] Subject: [AMRadio] Home Brew Hello All: I'd like to build my own AM transmitter. Tube style; more than 200 watts. Sure a heck of a lot to choose from...but I'd like to hear what you think. OR...if someone knows of a home brew for sale.... Tnx, Steve WA2TAK ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected]
