[Heathkit] SB-620 info

Thu, 12 Jun 2003 16:21:59 -0400

The March 1972 issue of CQ magazine had an article on using the SB-620 with
a 75A4.

Does anyone have a copy of the article they can scan and send to me?
or photocopy and mail, I will reimburse expenses.

73, Jim

> What frequency is it setup for now? Per the manual, changing to a
> different IF requires changing some parts. Or, if you know the IF the
> SB-620 is setup on, a simple outboard mixer to take the receiver signal
> and either up-convert or down-convert to the IF setup in the SB-620. I
> remember CQ magazine had an article on doing this with the HO-13.
> Pete
>
> On Thu, 12 Jun 2003 07:51:52 -0400 Jim Brannigan <[email protected]>
> writes:
> > I am taking another run at converting the SB-620 "Scanalyzer" to a
> > 455kc. IF
> >
> > Does anyone know the mixer oscillator injection frequency for a
> > 455kc
> > conversion?  It is not
> > stipulated in the manual or on-line sources.
> >
> > Here is my guess:
> > The IF of the Heath "Scanalyzer" is 350kc.
> > To convert 455kc., the oscillator may be either 805 or 105kc.
> > The "high" injection of 805kc produces first order products of 350
> > and
> > 1260kc.
> > "low injection of 105kc produces 350 and 560kc.
> >
> > The "High" injection products are further apart and it would be
> > easier to
> > filter the unwanted sum frequency.
> > So my "guess" is 805kc.
> > I know the value of the parallel capacitance.  If the oscillator
> > frequency
> > is known, I can calculate the coil inductance.
> >
> > Any help or ideas greatly appreciated.
> >
> > Jim> _______________________________________________
>
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