[R-390] R-390 slugs

Sun, 5 May 2002 10:33:05 -0400

Hi Bob,

It appears, from my research, that there are two series of R-390 slugs.  The
first series is for the earlier production runs of the R-390.  This is
discussed in the Final Engineering Report for the R-390, available at
www.r-390a.net/faq-refs.htm .  Apparently the earlier production runs used 3
different values of slugs in the R-390.

1.  For the 8-16, 16-32 RF coils, and the 9-18 Variable IF coils.
2.  For the 4-8 RF coils, and the 3-2 Variable IF coils.
3.  For the .5-1, 1-2, 2-4 RF coils.

They are not necessarilly matched to individual coils, but the type of slug
is selected for the above listed coil banks.

The second series of slugs, for later production runs, were poorly
documented in the 1962 TM 11-5820-357-35, page 3.

Nowhere is there a definitive explaination or graph detailing how to
identify the different values of slugs for replacement or alignment
purposes.  Some on the list attempted to chart their exhisting R-390 slugs,
to varying degrees of success.  This is documented in the Yahoo Archives as
discussed below.

I will continue to research this issue and report back from time to time.

Jim
73, KF4ICZ

----- Original Message ----- >
> Well, I have been going over the Yahoo archives and it seems that there is
> no easy way to judge what slugs and coils match in the R-390.  There was
> considerable discussion about color codes, etc.  Everything you ever
wanted
> to know about R-390 slugs is discussed in the April 1999 time frame, give
or
> take a couple of months, in the Yahoo archives, except the final,
definitive
> answer.  So it seems there is no real answer, beyong going back in time to
> question the manufacturers of these items. :-)
>
> Jim
>
> ----- Original Message -----
> From: "Jim Temple" <[email protected]>
> To: <[email protected]>
> Sent: Tuesday, April 30, 2002 10:58 PM
> Subject: Fw: [R-390] Question about R-390 (Non A)
>
>
> >
> > ----- Original Message -----
> > From: "Jim Temple" <[email protected]>
> > To: "Paul H. Anderson" <[email protected]>
> > Sent: Tuesday, April 30, 2002 10:56 PM
> > Subject: Re: [R-390] Question about R-390 (Non A)
> >
> >
> > > All the slugs, except one, had some kind of brown shellac coating
them.
> > One
> > > was black on the 16-32 slug rack.  I swapped this one with the one
coil
> > slug
> > > that was unstable, and the peaking instability went away.  Perhaps
> > somewhere
> > > along the way, the slugs were exchanged, hurting the stability of the
> > unit.
> > > It would be nice to have a comprehensive tally of the various
> combinations
> > > of slugs available in the R-390.
> > >
> > > Jim
> > >
> > > ----- Original Message -----
> > > From: "Paul H. Anderson" <[email protected]>
> > > To: "Jim Temple" <[email protected]>
> > > Sent: Tuesday, April 30, 2002 10:55 AM
> > > Subject: Re: [R-390] Question about R-390 (Non A)
> > >
> > >
> > > >
> > > > You're ahead of me on the 390 alignment, but one thing I do know is
> that
> > > > there are at least three different types of slugs for the RF deck -
> and
> > > > can for can, they change depending on the mod level.
> > > >
> > > > I'm away from my manual, but the 1962 390 manual (tm 11-5820-357-35)
> has
> > > > some info about slug changes.  David Medley had knowledge about
them,
> I
> > > > think, but didn't make it clear to me if he knew which color slug
went
> > > > where, or even if there was a scheme for that.
> > > >
> > > > We really, really (as a group) need to figure this out if we can - I
> > > > suspect a lot of 390/391's are suffering from mismatch of RF deck
> slugs.
> > > >
> > > > Paul
> > > >
> > > > On Tue, 30 Apr 2002, Jim Temple wrote:
> > > >
> > > > > Things have been a little slow, so thought I would ask a couple of
> > > > > questions.
> > > > >
> > > > > 1.  After aligning the RF section, the calibrator signal peaks at
a
> > > > > different position than where the antenna coils aligned.  I did
make
> > > sure
> > > > > that the antenna trimmer was at half mesh and did not touch it
> during
> > > the
> > > > > complete alignment.  Now, the antenna peaks at "0" and the
> calibrator
> > > will
> > > > > only put out about 1 volt diode load voltage.  The diode load will
> > peak
> > > at
> > > > > about 5 volts if I peak the antenna trimmer, which ends up at
about
> 2
> > > > > O'clock.  I tried to leave the antenna trimmer in the position
where
> > the
> > > cal
> > > > > is peaked, and realigning.  The realignment went fine, but the cal
> > > signal is
> > > > > still displaced at about 2 O'clock.  Adjusting the two trimmers on
> the
> > > > > Calibrator deck does nothing to move the peak to coincide with the
> > > antenna
> > > > > peak.  Does this anomaly suggest off value parts in the calibrator
> > > deck??
> > > > > Perhaps this is normal for the R-390?  On my R-390A both coincide
> > > perfectly.
> > > > >
> > > > > 2.  On bands below 16mhz, the antenna trimmer will peak with
> internal
> > > noise.
> > > > > At 16mhz and above, I can not detect a peak with internal noise.
> > > However,
> > > > > it will peak with an incoming signal.  My R-390A will peak with
> > internal
> > > > > noise on all bands.  Again, is this normal for an R-390?  I
> understand
> > > that
> > > > > the 16-32 coils, in earlier units, might have slugs and coils that
> do
> > > not
> > > > > realize the total potential that later units have.  Has anyone
heard
> > of
> > > > > this?
> > > > >
> > > > > Thanks for your past support.
> > > > >
> > > > > Regards,
> > > > >
> > > > > Jim
> > > > >
> > > > >
> > > > >
> > > > > _______________________________________________
> > > > > R-390 mailing list
> > > > > [email protected]
> > > > > http://mailman.qth.net/mailman/listinfo/r-390
> > > > >
> > > >
> > > > +---------------------------------------------------+
> > > > | Paul Anderson           Public Data Queries, Inc. |
> > > > | [email protected]             734-213-4964 x308         |
> > > > +---------------------------------------------------+
> > > >
> > > >
> > >
> >
> >
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>
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