>
>Rich says:
>
.........
>>During the grate parasitics debate, when we were discussing
>> gold->evaporation from an 8877's grid, I showed that RF grid-current in an
>> 8877 >(operating at its max. ratings of 4kV and 250MHz) exceeds 43RMS
>>amperes.
>
>This does suggest why you can get troubles with poor grid grounding
>techniques. Does the 8877 have a grid ring for a collet,
? Yes. Eimac makes a grid collet grounding device that has minimal L.
>.........
>Even a 3-500Z would appear to have 1.8 amps of RF in its grid connection at
>28MHz. This suggests to my mind that something better than disc ceramic
>capacitors ought to be used to bypass the grid.
? Kenwood, Heath and Drake used three, paralleled 500v mica capacitors
that were not current rated. It worked ok.
>I suppose that you can get away with a lot on SSB, but SSTV or RTTY really
>separates the men from the boys when it comes to reliability.
>
? Continuous is way different from SSB's 15% avg, duty cycle.
>
- cheers, Peter
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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