Like an AM kws1, power supply separate. The 4x150/4cx250b take no driving power, they run AB1, you can drive the grids with almost anything. Two problems, they need forced air, and they start working at 1000 volts... They also don't like to be plate modulated without a mod transformer with screen windings, hard to find.
They make great modulators, if you don't mind forced air blowers. 300 watts out at 1000 volts, 600 watts at 2000 volts. I have bunch as spares for my mod deck, but think I will go with something else... Brett N2DTS > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Geoff/W5OMR > Sent: Saturday, November 22, 2003 12:28 AM > To: [email protected] > Subject: Re: [AMRadio] FW: next project! > > > > > Geoff, > > I think you missed my point. > > I already have racks and racks full of homebrew rigs, pair of 813,s > > with various modulators, push pull 812A rig modulated by 811A's, > > plenty of parts to build a pair of 4-125 rf deck, etc, but > > what I want to build is a SMALL tabletop transceiver, both > the receiver and > > transmitter in one small cabinet like dx100 size or thereabouts. > > > > The receiver and transmitter will be homebrew and in the > same cabinet... > > John Coleman/WA5BXO had this idea a while back... > > How about a single 4CX250B modulated by a pair? > > The tubes are small and plentiful. An RF choke to the plate, > a coil tapped for 40/75 (wherever else) switched from the front panel, > final sub-assembly on top of, or in front of the modulator > sub-assembly > seperated by aluminum plate, or put the final in the right-rear corner > of the chassis, the modulator in the right-front corner of > the chassis, > aluminum "T" near the center of the chassis, to seperate the > rx/exciter, > and seperate the final from the modulator, build some small VFO that > controls both tx/rx, a varactor diode for RIT control, a > single IC w/PLL > for the VFO... lots of neat things can be done. > > 73 = Best Regards, > -Geoff/W5OMR > > _______________________________________________ > AMRadio mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/amradio
