I am in the early stages of lashing together a Harris RF-110 amp. It runs a
pair of 8122s in class A driving a pair of 4CX1500Bs. I am driving it with the
transverter output of my Kenwood TS-850, about 20 to 30 mW.
I'm sure that when mated to the proper Harris exciter, there is fool-proof
interlocking between the exciter and the amp - i.e. applying drive without HV.
I haven't yet found a convenient way to do this with the Kenwood. There are a
couple possibilities, but they involve feeding some signals out of the amp & if
you know the innards of this thing, additional output lines will be at least a
small challenge because of the physical layout of things.
Anyway - to the real question: Am I worried about a non-problem? If I apply
20 or 30mW drive to the 8122s without plate or screen voltage, will they be
damaged? The input is untuned and unswitched, fed directly to the grids of
the 8122s thru a .01uF cap. Looking at the datasheet for the 8122, the control
grid appears to be pretty tough - but grid dissipation per se is not specified.
I can't imagine a couple volts of RF doing any damage. WATSA?
By the way - this is a pretty nifty box. 20mW in, 1000W out, brick on the key,
no tune-up, etc etc.
Thanks! 73, Bill
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Bill Coleman N2BC
http://home.stny.rr.com/n2bc
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