[TMC] R5007/FRR-502 : Additional Info

[Tom Brent]

In June of 2004 there was a lengthy discussion of the FFR and R-5007
receivers by this group and it has prompted me to take a closer look at the
6 receivers and 19 tuning  units I have. First, the difference between the
AN/FRR-49 and AN/FRR-502 is explained on the second page of my copy of the
NAVSHIPS 0967-114-2010 manual. AN/FRR-49 consists of receiver subassembly
R5007, one or more of the tuning units, and tuning unit storage cabinet(s)
CY-5045A as required. AN/FRR-502 is a specific system consisting of one
R-5007 receiver and one each of TN5010 (2-4 MHz), TN5011 (4-8 MHz), TN5012
(8-16 MHz) and CY5045.

The difference between the R5007 and R5007A may be explained by a label
attached below the ID plate on a US Navy R5007 I have. It reads: "Modified
to R5007A/FRR-502 by addition of FC#1-AN/FRR-49(V) under contract NObsr
81202". A posting on here in June indicates that this change is the addition
of a resistor and bypass capacitor near resistor R-100.

I also have one of the receivers with a different tube complement.
Specifically, there is a 6BE6 at V103, 6FM8 at V104 and a 7199 at V107.
There is also a crystal filter installed in place of the 1st IF transformer.
Although I do not have a schematic for this unit yet, I am sure these
changes were to install a product detector and AGC improvements for SSB. I
am now aware of 5 of these radios and all of them are Royal Canadian Air
Force surplus. In the case of the one I have, it originally went into
service with the standard tube lineup and was subsequently modified. The 1st
IF transformer was obviously installed at one time and this is evidenced by
the impressions in the chassis from the lockwashers used to attach it.
Similarly, it can be seen that a 7 pin socket was once installed at V107
where the 7199 (9 pin) now sits. The script identifying the new tubes is
stamped in black ink as original but is in a slightly different style and
size.

If anyone can add to the information on these radios I would invite your
comment, especially if you can refute anything I have said here. I will post
information on the tuning units with a different tube lineup at a later
date.