[R-390] Mechanical Filters and "A" (was Hi)

Barry Hauser Barry Hauser <[email protected]>
Sun, 08 Jun 2003 10:41:04 -0400


Hi Todd

Well, there's a fly in that ointment.  For example, the R-1051 plain (not to
be called "non-A" to prevent extreme confusion if the 'R-1051" part is
omitted) -- what was I saying? -- Oh yeah -- the R-1051 plain has mechanical
filters and there was no known R-1051A.  The R-1051B and later also had
them.

Then (somewhat coincidentally) there is the R-105/ARR-15 and the
R-105A/ARR-15 whereby the crystal filter in the former was replaced by half
a tube (12SL7) in the latter.  This is the famous airborne receiver with 10
frequency autotuning and remote control for the pilot, etc.  Please do not
refer to it as an R-1051 non-1.  Non of -- uhhh -- none of these had
mechanical filters.

Of course, then there was the BC-348(x)'s.  Used up practically half the
alphabet, but only started with "E" -- no plains or A's through D's.  Seemed
to end with "S", but still no mechanical filters, at least as originally
equipped.  All sorts of things appeared on them installed by their 2nd, 3rd,
4th, etc owners until the practice fell out of favor.

There are plenty more examples.  Skipping to more recent history, and a bit
of a mystery, an RA6790GM just sold on that e-place for $1,325.  It was
fully loaded with six mechanical filters, instead of the usually smaller set
of crystal filters (or none at all).  That particular one still has its mil
tag "R-2174A (P), however just says "RA6790GM".  However, my understanding
is the "A" version referenced the added fault light and had nothing to do
with mechanical filters.

BTW Todd, The WD-40 Company, has asked me to ask you to please cease and
desist from using your call sign which they feel is a thinly veiled attempt
to defame their product.  Or it may be a complete random luck coincidence
and you're innocent -- but change it anyway.

Also -- to the group in general:  Please do not use "Hi" as a subject line.
It's rather ambiguous and resembles a lot of spam.

10-Q
Barry


Todd Roberts WD4NGG wrote:

> Hi John, thanks for your posting to the R-390 reflector. I cannot agree
that
> it is just random luck that the SRR-11A, R-390A and R-388A all have
mechanical
> filters. I have both the original SRR-11 and the SRR-11A with mechanical
> filters. The manual clearly states that the SRR-11A contains mechanical
filters.
> It is nearly identical to the SRR-11 except for the added mechanical
filters in
> the IF strip. Can you give me an example of a U.S. military radio receiver
> with the "A" suffix that does not have mechanical filters? Yours Truly,
Todd
> Roberts WD4NGG.
>