[Collins] Re: QRZ ALL R388 EXPERTS
Let me first thank all of you who have responded to my post on the R388.
All the answers were interesting and gave me food for thought.
I think that Ian has probably hit on what makes the most sense, at least to
me, considering the "every other band" phenominan. I am going to do an
alignment this weekend and I will let you all know what happens.
Thanks again to everyone's responses.
----- Original Message -----
From: Ian Webb <ian_webb@xxxxxxxxxxx>
Cc: <collins@xxxxxxxxxxxxx>; <collins@xxxxxxx>
Sent: Tuesday, December 12, 2000 9:39 PM
Subject: [Collins] Re: QRZ ALL R388 EXPERTS
> It seems to me that the ORIGINAL QUERY hasn't been carefully considered.
> it's been years since I've worked on an R388 or 51J I couldn't continue to
> on the sidelines mute so I dragged out my military manual for the R388.
> Sure enough, it states under "Variable Intermediate Frequency" that
> "The variable intermediate frequency consist of two ranges:
> one for a frequency of 2.5 to 1.5 mc, and the other for 3.5 to 2.5
> mc, used on even-numbered and odd-numbered bands, respectively.
> Using two variable i-f bands in this manner, cuts in half the number
> of crystals necessary in the h-f oscillator..."
> This should be an obvious clue to think about since the original post
> about EVERY OTHER BAND being off.
> >> The frequency alignment (the dial
> > > setting) seems to shift by the same amount as I change to every
> > > other band position.
> Hmmm.... wouldn't you think that might have something to do with the
> use of different IF frequencies??? For band segment 4 and up, on one band
> segment the signal goes into the FIRST MIXER and in the next it goes into
> SECOND MIXER using the different IF frequency on alternate bands.
> I'd sure want to do a careful alignment using a decent counter to set the
> frequencies used BEFORE I go off on a tangent of buying a whole set of
> to replace for fear that they are all bad with age. (Even without a
> alignment it would be possible to "split" the difference so bands were all
> within 2.5 kc of the same on the dial if you didn't want to do an
> Just my two cents worth!
> Ian, K6SDE
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