[AMRadio] 3-500Z @ 4 kV (Was: Johnson trannies...)


Kim Elmore cw_de_n5op at sbcglobal.net
Sat Jun 4 18:38:50 EDT 2011


Hi Rob,

Heavens!  No worries. Know anything about Globe Champions? :)

73,

Kim N5OP

At 05:35 PM 6/4/2011, you wrote:
>Hi Kim,
>
>I probably had incorrect information or did not remember it
>accurately.  Sorry about that.
>
>73
>
>Rob
>K5UJ
>
>On Sat, Jun 4, 2011 at 3:21 PM, Kim Elmore <cw_de_n5op at sbcglobal.net> wrote:
> > I changed the subject line so as not to continue committing a 
> thread hijack.
> >
> > I never looked into the IMD characteristics before I did this, to be
> > honest. Almost all my operating is CW, so that doesn't so much matter
> > to me. But I looed at the the spec sheet I have (c 1980) and it says
> > that 3rd order IMD is -40 dB at 3.5 kV and 5th order is -45 dB.
> > Nothing is listed for 5th order below 2.5 kV, so it must simply be
> > below -46 dB. The best 3rd order appears to be at 1.5 kV, where it's
> > -46 dB. Third order IMD increases to -33 dB at 2.5 KV, then stays
> > steady at -40 dB for 3.0 and 3.5 kV, where the table ends. Under load
> > (400 mA CW) I see about 3.6 kV B+, but with SSB or a two-tone test,
> > it's closer to 3.8 kV. Originally, the B+ dropped to about 2.7 kV
> > with 400 mA CW and was up around 2.9-3.0 kV with a two-tone test. It
> > may well be that the IMD isn't as good as it was, but probably isn't
> > too much worse.
> >
> > I can do AM with the amp and my Orion II, but I'd rather do AM with
> > my Dad's Globe Champion 350, but have a problem somewhere between the
> > VFO and the AX-9909 finals. Jim Wilhite and I have looked at it and
> > we're still scratching our heads as to just what's going on. I
> > strongly suspect that my problem is self induced, but for the life of
> > me can't find what I've done to cause it.
> >
> > The VFO is fine and doing exactly what it's supposed to do with the
> > output amplitudes it's supposed to have. It's somewhere in the 6CL6
> > buffer or 2E26 driver. The symptoms are strange: there's no drive for
> > 40-10 m and it doesn't act right on 160 and 80 m, either. Resonating
> > the grid no longer gives me the big peaks I remember. There's always
> > a background grid current of between 5-10 mA, and the peaks are not
> > the pin-bending amounts the rig had before I got into it. This Champ
> > has never "liked" crystals (slow to take off, if at all), but I have
> > a couple that work on 80 m. These act exactly as I'd expect, but when
> > I use the VFO, things change for the worse. But, Jim and I have gone
> > over the VFO and it seems fine in and out of the rig.
> >
> > If there are any other Globe Champ 350 aficionados out there that
> > have experience with the rig, I'm all ears!
> >
> > Kim N5OP
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