[R-390] 6082 tubes...

[David Wise]

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.

73,
Dave Wise


> -----Original Message-----
> From: Bob Camp [mailto:ham@cq.nu]
> Sent: Tuesday, December 31, 2002 8:17 PM
> To: Kenneth G. Gordon; r-390@mailman.qth.net
> 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" <keng@moscow.com>
> To: <r-390@mailman.qth.net>
> 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
> > R-390@mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/r-390
> >
> >
> >
>=20
>=20
> _______________________________________________
> R-390 mailing list
> R-390@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>=20