I have always wanted to try building one of those big amplifiers. One thing that stops me is that I have no idea where you get or how you build all the "sheet metal" parts --- complicated pieces of chassis, etc. Anybody out there who knows how people manage to build or source these?
Thanks. 73 de Brian W3BW -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Vic K2VCO Sent: Monday, May 22, 2006 12:40 To: michael taylor Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] QRO michael taylor wrote: > I'm curious, what makes RF amplifiers fairly expensive projects? Tube amplifiers are expensive because high power components (HV variable capacitors, high power bandswitches, power transformers, tubes, sockets, etc.) are expensive. In addition, although the basic circuit is quite simple, ancillary circuits to protect the expensive parts and provide functionality like QSK and automatic tuning are needed. Finally, the enclosure is large and must be well-constructed to be RF tight. A homebrewer can build an amplifier relatively cheaply by using surplus Russian tubes and scrounging parts. But you need to know what you're doing, since mistakes can be fatal. Transistor amplifiers are expensive because they are more complex. A KW amplifier may have 8 power transistors, and the protective circuitry may be more complicated than that for a tube amplifier. If you know that you will be driving a 50 ohm load, automatic tuning is simple; just switch in the appropriate lowpass filter for each band. However, transistor amps are unhappy with even a low-to-moderate SWR, so a built-in antenna tuner is really needed. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
