(c) 1999,2008 Peter McCollum
The RS-49 HF Radio Set
This set, which includes the RR-49 receiver, RT-49 transmitter,
and associated power supply, is a small agent radio similar in overall function
to the RS-6, but smaller and using all solid-state technology. It is an
excellent example of agent radio technology from the height of the Cold War.
Development of this set occurred in 1963 or early 1964.
Prototypes were built in CIA labs. Original production RR-49 receivers were
made by Collins Radio Company. A Collins schematic has dates starting at April
1964, with mods up to December 1965. The Collins manual includes copyright
dates of 1964, 1965, and 1966; the 2nd edition of the manual is
dated 1-Feb-66 (#523-0757606-00251D). A later model of the receiver, the
RR-49A, was made by Delco Electronics, as indicated by a Delco manual dated
November 1970. The RR-49A is nearly identical to the RR-49 – there are only a
few minor circuit changes. The manuals for the RR-49 and RR-49A are mostly a
match word-for-word, except for the Calibration chapter. No documentation has
been found for the RT-49 transmitter, so it is unclear who made it.
Note from a user:
This set was produced in our
lab and was the first to use 'sandwiched' technology by us. We had a very fine
clean room where prototypes were produced. Both sensitivity and selectivity are
good and it is quite stable. Our clean room was staffed by a bunch of little
country ladies... small nimble hands that were used to all kinds of needle
work. Good workers, but when they had a "poof" when working on a
board they teared up a bit.
The RR-49 receiver can be continuous-tuned, with a tuning dial
consisting of a tape that moves under a window; or it can be set to a frequency
via a front-panel crystal. It receives AM or CW signals from a random-length
wire antenna, and includes a 1 MC crystal calibrator. Power is supplied by
either a standard 9V battery in a rear compartment, or from the RS-49's 12V
power source when operating as a complete station. Controls include PWR
OFF/GAIN, BFO, XTAL IN/OUT, BAND, CAL, TUNE, and FINE TUNE. The TUNE and FINE
TUNE controls are mechanically operating the same tuning cap. The circuit uses
10 transistors: RF amp, mixer, IF amp (two), detector, audio, AGC, local osc.,
calibration osc., and BFO.
The RT-49 transmitter has some features that are reminiscent of
it's predecessors: three tuning controls and three matching indicator lights, a
connector to support a GRA-71 type of keyer (KE-8 keyer and CO/B-8C coder), and
a low-Z/high-Z antenna matching control. Power is applied through a DB-9
connector (the same type as is now used on PC serial ports). The power supply
has the mating connector, and sits directly beside the RT-49 when in operation
(there is no cable). The transmitter has a binding post for the receiver's
antenna, and there is an internal antenna change-over relay. The transmitter
supports a VFO input (unknown type). The circuit includes about 8 transistors,
3 of which are large power types (about the size of a TO-66 case, but without
the flange). The final stage appears to be 2 transistors in parallel in a
common-base configuration, each with a 2.5 ohm emitter resistor for current
balancing.
Through experimentation, the following has been learned about
the RT-49 transmitter:
·
Similar to the
T-784/GRC-109, the xmtr cannot be keyed without connecting something to the
‘Keyer’ connector.
·
The ‘Keyer’ connector
includes a pin which activates the T/R relay. Grounding this pin seems to be the
only way to close the relay.
·
The ‘KEY’ button on the
panel does not seem to operate the T/R relay, so perhaps it is only intended
for tune-up and receiver spotting. When the T/R relay is NOT on, the KEY button
turns on the oscillator and final to allow tuning to be adjusted. But when the
T/R relay IS on, the KEY button has no effect and the xmtr must be keyed via
the ‘Keyer’ connector.
·
The ‘Keyer’ connector pins
are compatible with the KE-8 keyer (from the GRA-71).
·
The ‘Ant. Load’ indicator
measures reflected power, so it only illuminates when there is a serious
antenna impedance mismatch.
|
RR-49 / RT-49 Specifications |
|
|
|
|
|
Receiver RR-49 |
Transmitter RT-49 |
Power Supply RP-49 |
|
Weight |
13 oz. |
about 1.5 lb. |
? |
|
Dimensions |
3-15/16" X 2-13/16" X 1-9/16" |
5-1/4" X 4" X 1-9/16" |
? (Similar to the RT-49) |
|
Frequency Bands |
2.970-6.150, 5.925-12.3, 11.850-24.600 MC. |
3-6, 6-12, 12-24 MC. |
|
|
Power input |
9V internal battery, or 12VDC external; 75 mw, average. |
24 VDC at about 0.6 amps max. |
12 VDC. |
|
Power Output |
1 mw into 2K ohms. |
About 10 watts max. |
Provides 24 VDC at about 1 amp for the
xmtr; 12 VDC for the rcvr; and a floating +/- 12 VDC to operate the KE-8
keyer. |
Other RR-49 specifications, from the Collins
manual:
·
AM
sensitivity: 10 db S+N/N, 0.1 mw, 15 uv input.
·
CW
sensitivity: 0.1 mw with 5 uv input.
·
Battery
life: 18-20 hours.
·
IF
frequency: 455 KC.
·
Selectivity:
3db, 5kc; 6db, 12kc; 40db, 16kc.
·
Audio
bandwidth: 300-2500 cps.
An RR-49 receiver. The dial pointer slides across
the window, to adjust for calibration at 1 MC points. There is some backlash in
the tuning dial (perhaps due to wear on the dial-tape), but the receiver is
stable otherwise. Author’s collection.
An RR-49A receiver. This image comes from the Delco
manual - note the serial number "000". The "T" shaped
protrusion is intended to protect the controls from damage. Image courtesy of
P.V.D.H.
An RT-49 transmitter. The entire top section comprises
a heat sink, with 5 devices mounted in it. The DB-9 connector visible on the
far left is the DC power input. The antenna/ground/receiver posts are in the
upper right, not visible. Note the 3-pin VFO connection – the center pin goes
directly to the power connector, and so is probably to provide DC power for the
VFO device. Author's collection.
An interior view of the
RR-49 and RT-49. Note the metal-tape tuning dial on the receiver; and the
unusual tuning caps marked “TRW” in the transmitter. The transmitter’s heat
sink contains 3 large transistors and 2 smaller devices. Some components have
date codes of early to late 1964, so these units were likely assembled in 1965.
Author’s collection.
An RP-49 power supply.
Visible on the right is the DB-9 connector that mates with the transmitter.
Another view of the RP-49
supply. The small 3-pin connector supplies power to the receiver.
Above are views of the RS-49
coder accessories.
On retirement, some CIA communications officers received a
plaque with an RR-49 mounted on it. This occurred until at least 1995, and
implies that there was some “old stock” equipment still being stored.
The RR-49 is reported to have been used by Belgian intelligence
(the Staatsveiligheid, lit. "state security"). However, apparently
the RT-49 was not included in that project - only receivers were delivered.
RR-49
receiver schematic (285 KB)
Click
to see the RS-49 set in a case.
Click
to see RS-49 tape-coder accessories.
The following table shows the connector pinouts for J-100
(power) and the Keyer connector on the RT-49 transmitter:
|
Connector pin |
Function |
Wire color |
|
J-100-1 |
GND |
|
|
J-100-2 |
+24 VDC input |
Red |
|
J-100-3 |
N/C |
|
|
J-100-4 |
+12 V supply to keyer (floating) |
Yellow |
|
J-100-5 |
-12 V supply to keyer (floating) |
Green |
|
J-100-6 |
N/C |
|
|
J-100-7 |
Rcvr antenna |
|
|
J-100-8 |
N/C |
|
|
J-100-9 |
VFO power? Goes to center pin on VFO conn. |
White/orange |
|
|
|
|
|
Keyer-A |
GND |
Black |
|
Keyer-B |
T/R relay control (active low) (not used by KE-8) |
White/red |
|
Keyer-C |
-12 V supply for keyer |
Green |
|
Keyer-D |
Keyed signal from keyer, active low thru a 1K resistor |
Blue |
|
Keyer-E |
+24 VDC (not used by KE-8) |
Red |
|
Keyer-F |
GND (keyed signal) |
|
|
Keyer-H |
+12 V supply for keyer |
Yellow |