>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?
** In Class A, there is no grid-current, so all of the exciter power
flows into the grid terminating resistor. If there is no 50-ohm grid
termination, your radio will likely be in a state of vexation.
> 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
** as I recall, the rated control grid dissipation is 2w max and the
screen is 8w.
>- 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
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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