[R-390] Staggertuned IF Question

[Barry]

Is it possible to switch filter covers between a straight-tuned deck and a
stagger-tuned deck?

Barry - N4BUQ

----- Original Message -----
From: "Cecil Acuff" <chacuff at cableone.net>
To: "Mark Huss" <mhuss1 at bellatlantic.net>; <Flowertime01 at wmconnect.com>
Cc: <R-390 at mailman.qth.net>
Sent: Saturday, September 16, 2006 9:52 AM
Subject: Re: [R-390] Staggertuned IF Question


> Good stuff....that's what I was looking for.  Some way to know when to do
> what.  Sounds like one can stagger tune or straight tune the dimpled cover
> decks...your choice depending on how you will use the radio but always
> straight tune the decks without the dimple.
>
> This probably needs to go into the Y2K book somewhere....and Pearls.
>
> Cecil...
> ----- Original Message -----
> From: "Mark Huss" <mhuss1 at bellatlantic.net>
> To: <Flowertime01 at wmconnect.com>
> Cc: <R-390 at mailman.qth.net>
> Sent: Saturday, September 16, 2006 8:22 AM
> Subject: Re: [R-390] Staggertuned IF Question
>
>
> > As I was taught (1975) at Devens (ASA), you tune using the Visual
> > Alignment and stagger tune flat on 16 kHz bandwidth. As an aside, it was
> > mentioned that if you ran across an IF deck with a filter cover with no
> > dimple, tune that one straght. No mention of replacing the IF Deck with
> > the newer ones. Making it meet spec was a big deal, since you did not
know
> > where it might be four years down the road. For 'Hogs' and 'RATT's' (
> > Morse Code Intercept and Radio Teletype) you could get a better noise
> > floor by straght tuning them, and we did that on special order, and made
a
> > notation with grease pencil on the IF Deck's filter cover.
> > R-390's and R-725's required sweep alignment for best operation. Never
> > bothered to do the three-point alignment on them (mostly R-725s).
Besides,
> > the point on them was to get flat phase shift through the IF deck, with
> > bandwidth being secondary. They were used for doppler DF, and phase
shift
> > could throw them off a few degrees, as well as widen the propeller,
making
> > direction more ambigous.