|
|
|
|
|
|
|
RX CIA Bugs Other → ← SRR-5
Apart from the antenna and any external audio equipment, the lightweight
receiver is fully self-contained and suitable for stationary or mobile
applications.
An external video device (panorama monitor) can be connected in order
to visualise a 5 MHz segment of the spectrum (90-1000 MHz).
The SRR-8 is a double conversion superheterodyne,
with four independent tuners, all driven by a common shaft.
Frequency readout is
through a bulged plexiglass lens at the left of the front panel,
behind which a film-type scale is moved.
Intermediate frequencies are at 25 and 6 MHz.
|
|
|
The receiver is powered by an internal removable
AC Mains Power Supply Unit (PSU)
that can be swapped for a battery pack
to allow portable and mobile use.
The unit measures 33.5 x 31 x 11.5 cm and weights just over 9 kg.
Development of the receiver at the TSD of the CIA started between
1958 and 1960. In 1960 the design was passed to the Radio Recepter
Co. Inc. (RR) in New York.
At RR, the receiver was further developed during
the course of 1960 [3]. The first prototypes — known as XRR-8 — were
released in 1961, and were so secret that each page of their
manuals
were stamped SECRET. It is believed that full production of the
SRR-8 started around 1963.
|
-
The Technical Services Division (TSD) of the CIA was renamed
Office of Technical Service (OTS) in 1974 [1].
|
All controls and connections of the SRR-8, with the exception of the mains
socket, are located at the front panel which is somewhat recessed
and has a hinged grip at either side. The front panel has a black
wrinkle paint finish 1 and is very similar to the front panel
of the earlier SRR-5 CIA receiver.
Central to the design is a clear yellow illuminated film-type frequency scale,
with an individual row for each of the four frequency bands.
To the right of the scale is the course/fine frequency adjustment knob.
The desired frequency band (1-4) is selected at the bottom right.
At the bottom right is the BNC antenna socket to which an external
antenna can be connected. Alternatively, a telescopic antenna can be screwed
into the antenna mount, located along the upper edge of the font panel. It can
be mounted in two ways, allowing the receiver to be used horizontally and
vertically. An IF output (video) is available for connection of a
panoramic display.
When using the SRR-8 on a desktop, the front panel could be
raised somewhat,
by fitting a short metal stub at the center of the lower edge of the
front panel.
This raised the front panel by some 8 cm and provided the operator with a
better view of the controls and the frequency readout.
|
 |
-
Some receivers had a white/blue finish.
|
|
The SRR-8 has four tuners, one for each band, that are all mounted to
the same tuning shaft. By operating the frequency tuning dial at the front
panel, the tuning shaft operates all four tuners simultaneously. Fine tuning
is possible thru a planetary ball drive that is mouned directly behind
the tuning knobs. For the two highest bands (3 and 4) an aditional fine
tuning is available (trim).
|
- 30 - 88 MHz
- 88 - 250 MHz
- 250 - 500 MHz
- 500 - 1000 MHz
|
|
The following additional equipment is required for proper use of the SRR-8:
|
|
Audio is provided at the 6.3 mm jack socket at the front,
at a level that is suitable for a pair of 600Ω headphones.
When using high-impedant headphones,
a 600 ohm shunt resistor should be connected in parallel. The socket
accepts a standard 6.3 mm mono jack.
|
|
|
An external antenna can be connected to the BNC socket at the front.
Alternatively, a suitable telescopic antenna,
such as the one supplied with the
SRR-4 or the
SSR-5, would be
appropriate for short-range reception.
The antenna shown here was supplied with the earlier
SSR-4 surveillance receiver,
and fits the antenna mount of the SRR-8.
|
|
|
When using the internal PSU, the receiver can be connected
directly to the 110V / 220V AC mains, by connecting the
power cable to a 2-pin socket at the rear, which can be
accessed through a small door.
In some cases, the door has
a hole through which the cable can be inserted.
As the original power cable is currently missing from the
receiver featured on this page, we have modified a common Winchester
Electronic plug to fit the existing socket.
|
|
|
The receiver is usually supplied with a removable internal
power supply unit (PSU) which is suitable for connection to
the 110V or 220V AC mains. The unit measures 175 x 80 x 42 mm
and is held in place by a metal bracket.
The PSU can be removed
without removing the outer case shell.
The desired mains voltage can be
set with a (mechanically protected) toggle switch.
The mains voltage should be supplied to the brown 2-pin
socket.
|
|
|
The SRR-8 could also be used as a portable receiver, in which case it
the mains PSU was removed and replaced by a same-size
Mallory battery pack SR2552-3 that was connected to the existing 5-pin
DC connector.
No image of the Mallory SR2552-3 is currently available.
It is unlikely that any of them have survived. The SR2552-3 can not be
found in any existing Mallory list, and was probably made especially for
the CIA.
|
|
|
The front panel of the SRR-8 can be
raised somewhat
for easier operation,
by screwing a metal stub into a threaded hole at the center of the lower
edge of the front panel.
The stub is approx. 6 cm long and has suitable
thread at one end. The image on the right shows the raised front panel.
|
|
|
The SRR-8 was supplied with a
51-page ring-bound manual, which contains
full operating instructions, circuit descriptions and circuit diagrams [A].
As the development of a 1 GHz receiver was quite special in 1961/63, both
the receiver and the manual were classified items.
➤ Download the manual
|
|
|
Below is the simplified block diagram of the SRR-8. At the top is
the antenna and the band selector, followed by four independent tuners,
all of which produce a 25 MHz IF-signal, which is fed to a 25 MHz bandpass
filter, an adjustable attenuator and then to the first IF amplifier.
After filtering and mixing with the 31 MHz 2nd IF oscillator, this results
in a 6 MHz 2nd IF signal, which is fed to the AM detector and,
via several limiter stages, to the FM discriminator.
Audio is then amplified in the AF stage at the bottom right to a suitable
level for 600Ω headphones.
A video output is provided by the 1st IF stage. It allows a 5 MHz band
segment to be visualised on a panorama display.
At the left is the mains power supply unit, which produces
three different voltages for the various electronic circuits.
It is suitable for connection to 110V and 220V AC networks.
The PSU is removable and can easily be swapped for a
battery pack of the same size.
For detailed circuit descriptions, please refer to the
original manual
which is available below [A].
|
|
The SRR-8 is well-designed and is very service friendly. Nevertheless
it is an extremely complex device that probably was difficult to repair
in case of a malfunction. Getting access to the interior is pretty
straightforward, an requires only 15 screws to be removed from the
outer case shell.
|
All internal parts are mounted to the front panel.
Once the 20 screws have been removed from the case, the entire
receiver can be pulled-out of the case shell. In the image on the
right, the bottom of the receiver is shown, revealing the front-end
of each of the four band tuners. The 25 MHz and 6 MHz IF and AF sections
are located at the rear.
In many cases, the transistors are socketed and are accessible from
the surface of each unit. This allows a broken transistor to be
swapped without removing and opening the individual units.
Most units are interconnected via coax cables.
|
|
|
All parts are mounted to a rigid metal frame that also holds the
front panel. The Power Supply Unit (PSU) is located in a metal bay
at the right side of the receiver and can easily be swapped for a
battery pack to make the unit portable.
Looking at the receiver from the bottom, clearly shows the four
individual tuners, one for each frequency band (1-4), as illustrated
in the diagram below.
At the rear side of the receiver are three more units: the 25 MHz
IF strip, which also houses the video detector, the 6 MHz IF strip,
which also contains the AM detector and the FM discriminator, and
the so-called MALO unit, which houses the mixer,
the audio amplifier and the local oscillator.
The diagram above shows the interior of the receiver, as seen from
the rear. At the left is a metal bay that holds the PSU. The PSU is
connected to the receiver by means of a slimline 5-pin power plug
(the large black disc). It is held in place by means of a metal
locking bracket at the bottom.
|
The actual PSU is housed in a small rectangular metal case that measures
175 x 80 x 42 mm. All connections and controls are at one of the short sides,
and can normally be
accessed through a door
at the receiver's rear panel.
After removing four recessed bolts, the lid can be removed and the interior
is exposed, as shown in this image.
Inside the PSU is a fairly small transformer that produces two secundary
voltages. Each voltage has its own bridge rectifier and stabilizer.
In total, three DC voltages are produced, which are available on
a 5-pin circular socket at the rear.
|
|
|
Device Countermeasures receiver Purpose Bug intercept and spectrum monitoring Principle Double conversion superheterodyne Designator SRR-8 Year 1960 Design TSD (CIA) Manufacturer Radio Receptor Company Country USA Frequency 30 - 1000 MHz Bands 4 Audio 4 mW into 600 Ω, 6% max. distortion Video 5MHz span, 0.1V minimum-high impedance IF1 25 MHz IF2 6 MHz Spurious rejection > 40dB Image rejection > 40dB FM limiter 1dB max, 10µV < Uin < 3000µV Dial accuracy 1% Temperature range -10°C to +50°C Dimensions 335 × 310 × 115 mm Weight 9 kg
|
- AM narrow band
- AM wideband
- FM narrow band
- FM wideband
- PM (pulse modulation)
|
IF1 12 MHz IF2 Wide: 250 kHz, narrow: 60 kHz
|
AM < 10µV at 6dB SINAD, with 30% modulation at 400Hz FM < 12.5µV at 20dB SINAD Pulse < 50µV at 10dB SINAD, with a 0.25µs pulse
|
AC in 110V or 220V (selectable) at 60 Hz DC 1 -14.5V ±0.5V, 60mA DC 2 -13V ±0.5V, 50mA DC 3 +11V ± 0.5V, 50mA Battery Mallory SR2552-3 (~50 hours)
|
-
Declassified in part and approved for release 5 December 2014:
CIA-RDP78-03153A000700020015-9.
Although the name of the company is redacted in the document, it is
present in the
original CIA file title
[2].
|
|
|
|
Any links shown in red are currently unavailable.
If you like the information on this website, why not make a donation?
© Crypto Museum. Created: Friday 25 November 2016. Last changed: Monday, 15 July 2024 - 07:35 CET.
|
|
|
|
|
