Tom says:
> >That's right Carl, using a series resistance and a shunt diode for
> >bias is just plain dumb.
Back in the late 1960's, RCA used a transistor feedback amplifier on the
bias because of these problems. It was in their RF power data book, and
worked fine - which is more than a diode and resistor does, unless
you're running several amps in the diode. It's not as if op-amps are
expensive, and 741's are quite good enough with a small plastic power
transistor.
To my mind, failure to put in a proper bias circuit is worse than dumb,
it's technical incompetance. Further, when you see manufacturers
claiming a 160watt amplifier for 'FM, SSB or CW!', and proudly telling
us we get 130 watts out for 20 watts in and 165 out for 55 watts in, I
really query the SSB bit. (October QST, p.177)
Touch of agreement on this one, folks.
73
Peter G3RZP
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