[Amps] Alpha 99 Exhaust vent temps

[Ron W4BIN]

   Hi  Warren NI5L:

> Hello all. I was referred to this list by Glenn, AE0Q, for an answer to my
> question about Alpha 99 exhaust temperatures. I am seeing about 155 to 160
> degrees F when running RTTY with 4.5 second transmissions at 500 watts.
> It doesn't really seem all that high to me but I would like to make sure I
> am not cooking the tubes. Has anyone here looked at exhaust temps and
> determined what a safe temperature range is? I am using an NIST traceable
> thermometer about ½ inch above the vents in the case, so the temps are pretty
> accurate.

   In my experiences the tube manufacturers specify air flow as a 
measure of tube cooling.
You might want to invest in a air flow meter if you  are concerned.
I am sure many finned anode tubes operate at a fin temperatures 
exceeding 230.º F in
broadcast use.
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