Hi Phil, I've seen similar approaches for regulating the heater voltage a vintage Russian military tube receiver. There's a series resistor in the circuit that's connected when the batteries are fresh-charged, and this resistor is bypassed with a switch when the battery voltage falls inside the normal operating range of the tube heater (there's an embedded volt-meter in the tube received for visual check, just like there's such menu in the KX3).
This method is less power efficient than when using a modern SMPS, but it's very "low-tech" and reliable (simpler systems have less and usually more obvious failure modes). 73, Nikolay // LZ1NRD ----- Цитат от Phil & Debbie Salas (dpsa...@tx.rr.com), на 13.05.2013 в 14:45 ----- > I put two 1N5400 diodes in series with each other (these are 3-amp diodes). > The diodes are physically side-by-side, with the leads connected in series to > keep the assembly small. This all fits nicely between two PowerPole > connectors and has a piece of heat-shrink over it. When connected between my > 4S2P LiPo battery (16.8VDC fully charged), I get 14.8VDC on receive, and > 14.2V with 2.2 amps on transmit at 10 watts. When the receive voltage drops > to 13V (as monitored on the KX3), I unplug the diode assembly. > > Maybe it is not elegant. But it is cheap, works great, and doesn’t generate > any hash. > > Phil – AD5X ------------------------------------- Mail.BG: Безплатен e-mail адрес. Най-добрите характеристики на българския пазар - 20 GB пощенска кутия, 1 GB прикрепен файл, безплатен POP3, мобилна версия, SMS известяване и други. http://mail.bg ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
