[R-390] HSR-2 vs 390a

[Cecil Acuff]

My guess is that his R390A is not as healthy as he thought it was.
Properly set up the 390A is a very sensitive receiver...from what I have
heard...right down to near the theoretical noise floor.  I can't imagine
there being that dramatic a difference and there not being a problem in the
390A in question.

Just my 2c worth!

Cecil...
----- Original Message ----- 
From: "Dan Merz" <djmerz@3-cities.com>
To: "R-390 List" <r-390@mailman.qth.net>
Sent: Tuesday, January 27, 2004 11:32 AM
Subject: [R-390] HSR-2 vs 390a


> Hi,  now I'm a relatively new guy on this reflector but I've gotten a
> lot of good information out of the questions I've put on here - and I've
> seen a lot of good information in the archives.  And I find the R390a I
> have is the receiver I use most often,  pretty much standard except for
> an audio improvement and substituting the 390 (non-a)  i.f. chassis.
> So I'm putting a somewhat general query out based on a recent article I
> read in Electric Radio,  Jan 2004 issue having to do with performance of
> an apparently pretty simple homebrew receiver vs. R-390a.  Just for
> information here,  the receiver consisted of 6be6 mxr, followed by 3
> i.f.  6ba6 stages and 6bj6 det.  etc. with no rf tube in front of the
> mxr,  just a couple of tuned circuits.  The full circuit is to come in a
> future article.   What caught my attention was the statement -
> "Comparison to my very well working 390a was dramatic,  I could CLEARLY
> hear signals that were well under the hash level of the 390a, but very
> comfortable copy on the homebrew receiver."  As best as I can tell,  the
> radio is being used on 40 meters and frequencies below that and
> primarily on AM.  I have in the past been made aware that rf stages in
> front of the first mixer are not so necessary below 20 meters,  probably
> first brought to my attention by the Squires-Sanders receivers and then
> later by advanced transistor receivers in QST.  But what I'm wondering
> about,  are there other factors that would make the 390a inferior in
> certain cases to a simple receiver as expounded in this article?   Dan.
>
>
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