[R-390] 6082 tubes...

Thu, 2 Jan 2003 11:01:59 -0800

Sorry, I gave the wrong doc name.  I meant the
Cost Reduction Report.  The Final Engineering
Report documents the design choices leading up
to the R-389 and R-390.  In my opinion, both are
riveting must-reads.  Check out how many tries it
took to get the R-389 frequency-changer topology.

73,
Dave Wise

> -----Original Message-----
> From: David Wise=20
> Sent: Thursday, January 02, 2003 10:24 AM
> To: [email protected]
> Subject: RE: [R-390] 6082 tubes...
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> In the R-390, they took the brute-force approach and
> regulated all B+.  During the Cost Reduction project,
> they found that the only really sensitive spots are
> the conversion oscillator screen grids.  In the R-390A,
> that's all that is regulated.  It's feasible to regulate
> this small load current with a VR tube.  With proper
> selection of circuit constants, this was found to be
> Good Enough.  They didn't even have to regulate the BFO
> screen.  The Final Engineering Report (available on the
> FAQ page) goes into some detail on this, and it's a
> fascinating read anyway.
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> 73,
> Dave Wise
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> > -----Original Message-----
> > From: Bob Camp [mailto:[email protected]]
> > Sent: Tuesday, December 31, 2002 8:17 PM
> > To: Kenneth G. Gordon; [email protected]
> > Subject: Re: [R-390] 6082 tubes...
> >=20
> >=20
> > Hi
> >=20
> > They dropped the 6082's from the 390A radios. The only=20
> > regulation on the B+
> > comes from a normal VR tube arrangement. This took a major=20
> > amount of heat
> > out of the radio.
> >=20
> > As far as anybody can tell this does not create a problem=20
> > when run off of
> > normal line voltage.
> >=20
> >     Take Care!
> >=20
> >         Bob Camp
> >         KB8TQ
> >=20
> >=20
> >=20
> > ----- Original Message -----
> > From: "Kenneth G. Gordon" <[email protected]>
> > To: <[email protected]>
> > Sent: Tuesday, December 31, 2002 10:21 PM
> > Subject: [R-390] 6082 tubes...
> >=20
> >=20
> > > I have never owned an R-390-A (although I hope to someday), but
> > > I have owned an R-390 and I presently have an R-389. Both of the
> > > latter have a pair of 6082s in them as shunt regulators.
> > >
> > > Does the R-390-A have the 6082s, or did Collins eliminate those in
> > > the interests of economy?
> > >
> > > Ken Gordon W7EKB
> > > _______________________________________________
> > > R-390 mailing list
> > > [email protected]
> > > http://mailman.qth.net/mailman/listinfo/r-390
> > >
> > >
> > >
> >=20
> >=20
> > _______________________________________________
> > R-390 mailing list
> > [email protected]
> > http://mailman.qth.net/mailman/listinfo/r-390
> >=20
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