[Hammarlund] 6C4 issues - progress ! (was dead on 15m HQ-170a)

[Ken Kaplan]

Hi Glen,

I have heard this about using the unit itself as the tube checker and I understand why. But 
are you suggesting that a tube that measures low in an emissions test may work just as well 
as a tube that measures high in the same test? Even more odd, it sounds like you may be 
saying that the opposite may sometimes be true (high emissions = poor performance and low 
emissions = good performance).

If such is the case, then it seems to me that the emissions type testers are not testing 
enough. Actually, I think we probably all agree on that <g>. But I'm guessing that even a 
transconductance tester is not totally sufficient? Maybe that Tektronix 570 Curve Tracer I 
passed up a few years ago would be the ticket. Then again, I could buy a lot of tubes for the 
price of that beast.

What do you think? Is emissions and/or transconductance testing a waste of time?

73 Ken kb7rgg

> This is exactly the reason that I say the best tube checker in the
> world is the unit itself.  I have seen a lot of occasions where a tube
> would check "good" in a tube tester and not work at all in the radio. 
> Then other tubes check bad in a tube tester and work fine in the
> radio. 
>
> Glen, K9STH
>
> Website:  http://k9sth.com