[R-390] Ballast Tube Thread

[John Page]

John Page K4KWM
Hollow State since 1953
(ex W8PKU,N8BLB,NA8O)

Jeff Daniels also played a Union Civil War officer in the movie "Gettysburg" 
and did a fantastic job. John



>PS -- As I write this the History Channel is playing "The Crossing" with
>Jeff Daniels as G. Washington.  Am I mistaken, or didn't he play opposite
>Jim Carey in "Dumb and Dumber"?  Either (a) I don't know how I feel about
>that, being rather fond of the original George and/or (b) Jeff D. has quite
>a range and may qualify as the worlds most underrated actor -- tho' I
>wouldn't mind trading paychecks.
>
>
>
>----- Original Message -----
>From: "JamesMiller" <jmiller1706 at cfl.rr.com>
>To: <r-390 at mailman.qth.net>
>Sent: Sunday, July 04, 2004 11:11 AM
>Subject: Re: [R-390] Ballast Tube Thread
>
>
> > >From page 15 section 4.2.2.1 AC Power Units of Final Engineering Report
>on
> > Radio Receivers R-389 and R-390 Sept. 15, 1953:
> >
> > http://www.r-390a.net/faq-eng-r3.pdf
> >
> > "The filament regulation circuit for the oscillator filaments should 
>also
>be
> > covered here although this ballast tube is mounted on the IF unit.
> > Considerable work was done with Amperite Corp. in designing this special
> > ballast tube which feeds a constant 300 mils to the two 6 volt 300 mil
> > oscillator tubes used in the VFO and BFO. These three tubes are 
>connected
>in
> > series across the 26 volt filament supply. The ballast tube (3TF7)
>operates
> > on a current of 290 to 330 mils and holds this current within ±10 mils 
>for
> > input voltage variations of ±15%. This reduced the 15% variation to
> > approximately 3%. There is some question if a filament regulator is
> > necessary in these receivers since the oscillators are very good even
> > without regulation. However, since the stability was a big factor in 
>this
> > design and since the factor of tube aging was not known, the regulator 
>was
> > included."
> >
> >
> >
> >
> >
> > _______________________________________________
> > R-390 mailing list
> > R-390 at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/r-390
> >
>
>
>_______________________________________________
>R-390 mailing list
>R-390 at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/r-390

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