[Swan] tube testing

[Kenneth G. Gordon]

Well done.

Ken Gordon W7EKB

On 20 May 2007 at 8:50, w7lrd at comcast.net wrote:

> Hello (again)
> I'd like to bounce this info off a few of you who responded to my
> prior emails about testing PA tubes. I have about three dozen
> 6LQ6/6JE6/6MJ6 PA tubes that I have been collecting over the years and
> didn't realize I had such a stash.  I used my favorite 350C,
> disconnected the B+ from one of the PA's, used the same socket for
> testing,  All I adjusted was to peak the PA plate and PA grid for each
> tube.  I recorded the power output as read on a Swan WM-3000.  This
> may or not be accurate, all I wanted was a relative indication for
> comparison.  I also recorded the Ip for each tube.  This way I can
> pair up a couple of tubes that are fairly close in capability. Prior
> to evaluating I neutralized the PA with one tube conducting.  One of
> the tubes took off like the 4th of July inside, lots of pretty arcs
> and sparking going on,  I really flew out of the chair.  Now, be weak
> or not I have some fairly closely matched PA's.  A couple of good ones
> will load up to over 550 MA and according t
>  he the
>  WM-3000 and are putting out over 300 watts.  This was done on 20
>  meteres, obviously the output will be lower on 10 & 15.   About 10
>  went right to the trash, zero or less that 5 watts output.  I will be
>  doing the same thing with some 6LB6's which are a 6 volt version of
>  the 8950, in one of my 700Cx'.  Your comments and or observations
>  please.
> 
> --
> 73 Bob W7LRD 
> AMSAT member 28498 
> Seattle
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