>> the tube still usable or should I send it back to the guy I got it from?
>
>Why don't you install a proper fault protection resistor and try
>again.
What do you call a proper fault protection resistor? I did have two 10
watt 10 Ohm wirewounds in series right after the HV DC bypass caps at the
DC entrance point to the RF deck. They opened up during the arc or
whatever. I just have to get new ones. Isn't that a proper fault
protection resistor?
>
>> OK. The series resonance of the plate RFC is around 23 to 24 MHz. Is
>> this perhaps a little too close to 21 MHz? Perhaps putting the lid on
>> lowered the resonance. I'll have to check for that. I was wondering if
>> that might be the case.
>
>That's pretty darned close, but workable in most cases. You
>absolutely need to measure it with the cover on. I know you like
>using the GDO, but there are MUCH better tests.
>
>One is to use a resistor, diode, and signal source to measure choke
>impedance. The problem (I hear an echo) with a GDO is it tells you
>nothing about choke impedance.
Yes, yes, I know. The GDO doesn't measure impedance. I hear that loud
and clear. All it measures is resonance. So how do you measure
impedance with a resistor, diode and signal source? Are you talking
about making a noise bridge or something? Enlighten me.
>
>> Chalk it up to inexperience with tubes again. I always thought gassy
>> tubes are typically tubes nearing the end of their useful life and that
>> during that time, gain and such would begin to fall off.
>
>Might or might not. Brand spanking new tubes with lots of emission
>are sometimes gassy, so are old worn out ones.
OK. Interesting. I thought it was just old tubes that got gassy.
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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