Don: You got it right!
An old AM/FM Broadcaster, Roger Agnew K1KQ - Austin, TX 888-536-5500 ----- Original Message ----- From: "Donald Chester" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, August 17, 2004 6:08 PM Subject: Re: [AMRadio] filament voltages > > > > >> > >Of course, we know that running voltages that are too high will kill > >>the > > > >life expectancy of the tube, by why is running too little voltage bad > >for the > > > >tube, if it's developing full emmission at a lower voltage? > > > > > If the lower filament voltage does not affect the emission of the cathode at > peak plate current, it will not harm the tube. But even if the average > plate current seems normal, but the lower filament voltage limits the peak > even slightly, tube life will suffer. > > The procedure with an AM transmitter is to modulate the transmitter to its > maximum positive peak capability, with full filament voltage. Then reduce > the filament voltage until you begin to notice a dropoff of the positive > peaks. Run the filament voltage back up just past the point where positive > peaks are fully restored. The point is to run the filament just above the > first indication that the cathode is being starved of emission. > > Don K4KYV > > _________________________________________________________________ > Express yourself instantly with MSN Messenger! Download today - it's FREE! > http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > >
