First, we have to assume Rich is unbiased and telling the truth.
Assuming that:
> At 2250 watts output, an 8877 draws less than 65 ma grid current.
> 75 ma limiting is plenty of headroom. A cap sits in the base circuit
> of the TIP120 to prevent nuisence trips.
75 mA is not plenty of headroom Phil.
At 3300 volts anode, a typical 8877 requires 125 mA of grid current
to produce 2500 watts output, At 125 mA of grid current, grid
dissipation is 11 watts.
At 175 mA, grid dissipation is 18 watts.
These figures are from Eimac's tube calculation software.
> > Ever ran an 8877 with no suppressor whatsoever?
>
> I have not personally, but if you look at old Orr and ARRL Handbooks, you
> will see several 8877 projects sans the Supp.
All of this hysteria is caused by one person. Eimac has never
found a "VHF sputtered grid" in an 8877 returned from an Ameritron
amp.
73, Tom W8JI
w8ji@contesting.com
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