[Milsurplus] Transplanting R-390 IF modules to R-390A

[mikea]

On Fri, Feb 02, 2007 at 09:07:22AM -0500, Ray Fantini wrote:
> Ok, so maybe its a stupid question but why would you want to substitute
> a IF deck with mechanical filters to one without? What's the benefit? I
> have heard rumbling before about the A not being as good as a regular
> 390 and thought the filters were the only difference, well maybe that
> and the squelch.

The mechanical filters tend to "ring" a bit, in my experience, where 
the LC filters don't. If you need better phase-flatness across the
filter passband, the LC filters are preferable to the mechanical ones,
and it's my understanding that that's why the R-725 RDF receiver used 
the R-390 IF deck in the R-390A chassis. 

I could be all wet, of course; it wouldn't be the first time. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin