[Amps] Ameritron Amps

[Tom W8JI]

>>>When the Chinese were making 3-500Z tubes with regular 
>>>glass
>>>and holes were sucking in the sides, Rich concluded it 
>>>was a
>>>VHF parasitic that couldn't be seen or measured. This VHF
>>>oscillation supposedly caused dielectric heating of glass 
>>>at
>>>VHF.
>>
>>
>> Correct.  Rus Healy at QST was the first who told me of 
>> this
>> phenomenon.  However, it took Eimac a while to come up 
>> with a glass
>> recipe that would not melt at VHF, so I was not surprised 
>> that the
>> Chinese initially encountered the same difficulty.
> Do you know when this was? I'd like to know which date 
> codes to avoid.

Steve,

The Chinese tube problem was NOT VHF heating as Rich 
claimed. The Chinese used regular glass and the tubes melted 
even with no RF applied.

What I said was Rich **concluded** it was a parasitic.

I'm not aware of Eimac ever having that problem or any 
similar problem. It makes no sense at all to think they 
would.

The Chinese tubes are long gone. They were early Chinese 
tubes.

73 Tom