[AMRadio] Collins R390/URR versus R390A

Todd, KA1KAQ ka1kaq at gmail.com
Thu Mar 13 13:01:14 EST 2008

On Thu, Mar 13, 2008 at 1:43 PM, D. Chester <k4kyv at charter.net> wrote:

>  The mechanical filters result in tighter selectivity, but at the expense of
>  nonlinear phase shifts inherent to mechanical filters.  That is what causes
>  the harsher audio quality in the A version, as well as in receivers like the
>  75A-4 that use mechanical filters.

A couple of other issues with the R-390 are excessive heat from the PS
rectifiers and additional weight. Neither are show stoppers though,
and like Don, I also prefer the original model R-390 to the later A
model for overall utility. Both are excellent rigs, and pulling the
audio off the rear apron diode load connections, then feeding it
through a decent external audio amp will drive a big speaker with
amazing audio resulting.

R-390s tend to be a bit less available due to lower production
numbers, but they're available without much searching. And, contrary
to the new-age 'non-A' myth, both radios are indeed R-390 receivers,
with the latter, cost-reduced version nomenclature appended as the A.
Makes more sense to refer to a radio by what it actually is, rather
than what it isn't. (o:

~ Todd,  KA1KAQ

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