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← USA Cold War CIA SF
CIA spy radio set
TAR-224 was a highly compact self-contained spy radio set,
developed around 1970 by AVCO Corporation in Cincinnati
(Ohio, USA)
for the US Central Intelligence Agency (CIA),
as a successor to the ageing
GRC-109 (RS-1) of the 1950s.
It was intended for communication with field agents behind enemy lines.
Due to mechanical and electrical problems, nearly all units were
reworked by WES Industries
in 1972 [6].
After a long operational life,
it was phased out in the late 1980s.
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The entire unit is completely waterproof, with all switches and controls at
the front panel properly sealed, allowing the radio to be stored under
harsh conditions for an extended period of time. A plastic lid can be placed over
the controls to protect them against dust and dirt. It is held in place by
three metal latches at the edges.
The image on the right shows a typical TAR-224A unit, without the optional
CS-224 30-channel crystal selector
installed. The unit roughly consists of
two parts: the receiver (RX) at the left,
and the transmitter (TX) at the right.
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The radio covers all frequencies between 2 and 24 MHz. The receiver has
a Variable Frequency Oscillator (VFO), allowing continuous tuning of all
4 frequency bands, whereas the transmitter is crystal operated.
The unit can be powered by an external 12V source that is connected
to a 3-pin socket at the front left, or by a special
12V battery pack that is installed behind a
watertight panel at the front left.
A plastic grip,
at the left of the radio, allows the unit to be carried around easily.
The TAR-224 was introduced in 1970 and the user manual was updated
once in September 1971. The unit shown here, was probably issued in the
early 1970s, and was last inspected in 1976.
Most TAR-224 units were used by the CIA on special (overseas) missions [4],
but the radios were also used by intelligence services in Europe [1].
It is known to be used on a mission in Angola in 1975.
According to CIA communication specialist Teddy Roberts,
the TAR-224 was still being used in operational context in 1983,
when he trained a unit of US Army Green Barets on its use.
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PLEASE HELP —
Little is known about the operational use of the TAR-224, so we'd like
to hear from people who actually worked with it in the field.
Furthermore, we are looking for the optional CS-224 Channel Selector that
can be installed in the empty slot in the top right corner of the radio.
If you can help, please contact us.
The image below gives a good view of the TAR-224 controls and connections.
The left half of the radio contains the receiver (RX), whilst the right
half contains the transmitter (TX). The two sections are separated by a
vertical white line at the center. The radio can be powered by an internal
12V battery, but also by an external power source that is
connected at the bottom left.
The receiver has a Variable Frequency Oscillator (VFO) that can be adjusted
to any frequency between 2 and 24MHz, but the transmitter requires a suitable
crystal for each TX frequency. The crystal is inserted into a special socket
at the bottom of the TX section. At the top right is room for an expansion
unit, such as the CS-224 crystal selector
or a digital frequency synthesizer.
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Overseas use of the TAR-224
Teddy Roberts started his professional life back in 1960 when —
fresh out of high school —
he attended a Radio Intercept Operator's Training
in Imperial Beach (California, USA).
After passing a Naval communications training later that year,
he got his first assignment at the US Naval Communications
Facility in Adak (Alaska), where he learned to work with
sophisticated high-powered computers, video display terminals
and the collection and analysis of communications signals.
In 1963 he was transferred to the Naval Communications Station
in Honolulu (Hawaii).
In 1964, following his release from the US Navy, he
entered communications training with the CIA, after which he
was assigned to the American Embassy in East Africa.
Later that year, whilst being on medical hold for any overseas posting,
Terry was temporarily assigned with an engineering office at
the CIA's communications training facility.
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After his medical hold had been cancelled in 1965,
he was assigned to a US Embassy in West Africa.
In the following years, he worked in several countries
including Germany, Libya, Israel, the Phillipines,
and China, until he landed in London (UK) for a five-year
assignment with the US Embassy. During these years he worked
closely with the British Intelligence services in support
of NATO war planning programs.
In 1988, he was assigned to CIA Headquarters in
Virgina, where he worked as chief of recruitment for the CIA's
Office of Communications. A few years later he was assigned
as Deputy Chief of Operations
of the Communications Area Operations staff for Africa.
In 1992, Terry was assigned as associate director of the
CIA's Global Network Management Center, planning the CIA's
world-wide communication needs on a daily basis, until he
retired from the CIA in 1995.
The image on the right shows Terry Roberts holding a TAR-224A in
his hands. He used this radio in an operational context in 1983,
when training a unit of Army Green Berets on its use.
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One of his most memorable experiences was his involvement
in the arrest of Daulton Lee and his partner in crime
Crystopher Boyce, during a three-year tour in Mexico,
where he worked in close cooperation with the FBI.
Whilst working for US defense contractor TRW,
Boyce used a Minox-B spy camera
to copy classified government information,
which Lee sold to the Soviets.
Lee and Boyce were eventually arrested in 1977,
and were sentenced to life and 40 years respectively.
The story was later told in the 1979 book
(and later in the 1985 movie)
The Falcon and the Snowman.
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THANKS —
The above story was extracted from the article
Teddy Roberts spent 40 years working for the CIA around the world,
written by Elaine Blaisdell and originally published on 28 February 2009
on The Journal (website) [4].
Many thanks to The Journal and to Elaine Blaisdell
for allowing us to reproduce part of that story along with the
photograph which was also made by Elaine Blaisdell.
Personal account of a WES employee · 1971-1972
I had the dubious fortune to work on scores of them when I worked
for WES Industries in Dumfries, VA in 1971-1972.
Evidently, AVCO had run out of resources when the time came to ship,
with the result that the TAR-224 units were shipped without final
testing; and as a consequence most of them didn’t work.
WES Industries must have been the low bidder to put them in working
order — we were frequently the low bidder on security projects of this kind.
I was one of two techs tasked with bringing them to operational condition.
Christhelm Ranald Kocherhans and I disassembled each of the units, made
modifications to improve/attain reliability, fixed the known problems,
troubleshot where necessary, and ran burn-in tests before returning them
to the customer.
The most frequent reliability issues related to solder connections to the
ground plane on the back of the receiver printed circuit boards. Although plated-through
holes were a known technology at the time, AVCO made the through-board
connections with eyelets. I don't know what those eyelets were made of,
but they wouldn't take solder. We often resorted to soldering a short
length of wire through the holes to pads on each side of the board.
I used to keep a big, black shingling hatchet on the wall above my bench,
engraved with 'TAR-224 Final Test'. I have that hatchet to this day.
Thanks for reminding me of those frustrating days of my misspent youth.
I have attached the WES Industries proposal, the TAR-224 test setup document,
the QC sheet for final test, and hand-drawn instruction documentation.
➤ See the original WES Industries documents
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The image on the right shows the bare TAR-224 transceiver, which is fully
self-contained. It is powered by an internal battery
and requires the installation of a quartz crystal,
an external (wire) antenna, and a handset.
The unit can be covered with a plastic lid that is held in place by three
spring-loaded clips at the edges.
When all options are correctly fitted, the unit
is water-tight, allowing it to be stowed under harsh and moisterous conditions
for an extended periode of time.
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The TAR-224 was usually powered by an internal rechargeable NiCd battery
pack that provided the necessary 12V DC power supply. It consists of 10
cells of 1.2V each, and can be charged in-situ by means of the
EMBC-224 battery charger.
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The NiCd battery pack can be charged in-situ by means of the EMBC-224
battery charger shown in the image on the right. It should be connected
to the AC mains, by means of the external mains power cord that is also
shown.
The charger has a hinged lid
below which a fixed 3-pin power cable is stowed.
This cable should be connected to the power socket
at the front panel of the TAR-224.
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The TAR-224 can also be powered by an external 12V DC source, such as the
battery of a car, or by the purpose-built Power Supply Unit (PSU) shown in
the image on the right.
The PSU should be connected to the 3-pin power socket at the front panel
of the TAR-224. As soon as an external 12V DC voltage is supplied, the
internal battery is disconnected.
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In order to reduce the chance of interception and discovery by means of
radio direction finding (RDF), a high-speed burst
transmitter, or keyer, can be used.
It allows pre-recorded (preferably encrypted)
messages to be sent at speeds up to 300 wpm,
and reduces the on-air time.
The image on the right shows the KE/M-8 keyer that was supplied with the
TAR-224. It is the motor-driven version of the KE-8, which uses a spring-loaded
wind-up mechanism.
➤ More about the CK-8 coder/keyer
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Messages were pre-recorded on a tape cartridge that was installed
on the CO/B-8 encoder shown in the image on the right. The coder has a large
disc at the top, which allows any of the 26 letters of the Latin alphabet to
be selected. By operating the lever, the selected letter is recorded onto
the tape in morse code.
The coder does not require an external power source. Instead, the
energy that is required for its operation, is generated by a miniature power
generator that is operated by the lever.
➤ More about the CK-8 coder/keyer
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The image on the right shows a typical tape cartridge, of which several were
supplied with the radio set. The cartridge can be installed on the
coder in order to record a (preferably encrypted) message in morse
code.
Once the message is complete, the cartridge is removed and installed
on the keyer, which in turn is connected to the TAR-224. When the
start button at the rear of the keyer is pressed,
the message will be sent at 300 wpm.
➤ More about the CK-8 coder/keyer
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When using the TAR-224 for speech (phone), a microphone/speaker combination
– such as the handset shown in the image on the right –
should be connected to the 6-pin
U-229 socket marked PHONE at the front panel.
The handset has a so-called push-to-talk (PTT) switch at the side. Pressing
the switch enables the transmitter. Releasing it enables the receiver.
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When using the TAR-224 only for messages in morse code – for example in
combination with the burst keyer – it is recommended to use
a headset instead of the handset shown above, as a microphone is
no longer required.
The image on the right shows a typical headset that was commonly supplied
with a TAR-224.
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When using the TAR-224 in the field, the mains power network might
not be available. In such cases it is possible to power the transceiver from
an external 12V DC power source, such as the battery of a car, using the
cable shown in the image on the right.
The cable has two large crocodile clips at one end, for connection to the
battery terminals. The other end has a military 3-pin plug that should be
connected to the power socket at the front panel of the TAR-224.
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The TAR-224 has a slot in the upper right corner, in which a crystal selector
can be fitted. It gives the transceiver the ability to quickly switch between
30 pre-installed channels.
No image available at present
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The slot in the upper right corner of the front panel — normally used for
an optional crystal selector —
also accepts a digital frequency synthesizer, which allows the desired
frequency to be selected by means of thumb-wheels.
Apparently, a small series of synthesizers was professionally manufactured,
and was housed in the modified enclosure of a crystal selector.
Additional information will be added later
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The TAR-224 requires a single wire antenna to be connected to the ANTENNA
terminal at the right edge of the front panel. When tuning, the internal
motor-driven antenna matcher, will try to match the antenna. If it fails to do
so, a different antenna length should be tried.
Furthermore, it is important to connect a proper ground
(counterpoise) to the GRD terminal (just below the ANTENNA terminal).
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The transceiver consists of the following functional blocks:
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At the bottom of the front panel
are the MODE-selector,
the Beat Frequency Oscillator (BFO),
AF gain (volume) and RF gain (HF pre-amplifier).
When the RF adjustment is set to the leftmost position, the Automatic
Gain Control (AGC) is enabled.
The receiver also contains the POWER switch
and the connectors for
external power, microphone, speaker and external morse key.
The frequency scale can be calibrated by setting the MODE-selector to
CAL. This enables the built-in reference oscillator, which produces
a carrier at 500kHz intervals (3MHz, 3.5MHz, etc.).
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Once the reference oscillator is selected, tune the receiver to a carrier near
a rounded frequency (e.g. 3MHz) and
adjust the scale ruler (CAL ADJ) so that its
center positions lines up with the frequency.
The receiver is suitable for the reception of morse signals (CW)
and voice (AM), but can also receive Single Side Band signals (SSB)
by the using the built-in Beat Frequency Oscillator (BFO). For normal
operation (CW) the BFO should be set to the center position (0).
For SSB signals, the BFO knob can be tuned
(-) for Lower Side Band (LSB) and (+) for Upper Side Band (USB).
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The transmitter is crystal-operated and is
suitable for CW (morse) and AM (voice) communication. A suitable
CR-18/U crystal can be inserted in a special socket at the front center.
If rapid channel selection is needed, an optional
crystal selector
can be installed in a special slot at the top right. If the selector
is not installed, the slot is closed by a thick plexiglass panel.
It is also possible to install a
digital frequency synthesizer — controlled by five thumb-switches —
in this position.
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When using the (optional) channel selector, three banks of 10 channels
each are available. When a single crystal is inserted into the
crystal socket at the front panel, the 30-channel selector
is disabled.
Two frequency ranges are available via a selector:
2-12MHz and 12-24MHz.
In the 12-24MHz mode, the crystal frequency is doubled.
When sending messages in
morse code, the TAR-224 was normally used
in combination with a burst-keyer, in order
to avoid detection and interception by a potential eavesdropper.
The standard burst encoder was the CK-8 (GRA-71).
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Alternatively, a morse key could be connected to one of the
6-pin U-229 connectors at the front left,
allowing manual transmission of morse signals. In case of an emergency,
the built-in morse key could be used for
this as well. The minimum output power for an unmodified TAR-224 is specified
at 13W in CW and 4W in AM, but in practice the output power was much higher.
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The radio shown here delivers 21W in CW and up to 8W in AM [3].
When used for phone (voice), a handset or headset
could be connected to one of the 6-pin U-229 sockets at the front left.
The (wire) antenna and a suitable counterpoise should be connected
to the two snap-on terminals
at the right edge of the transmitter.
The TAR-224 has a built-in Antenna Matcher that allows the transmitter
to be adjusted for the (wire) antenna in use. This can be done by
holding down the morse key whilst manually rotating the antenna
tuning knob at the right.
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Alternatively, the Automatic Antenna Tuner (AAT) can be enabled by
pulling-out the antenna matcher knob.
This engages a novel electronically controlled motor-driven
coil mechanism that will try to obtain the highest power output at the
best possible Standing Wave Ratio (SWR).
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The TAR-224 should be powered by any 12V DC source that can deliver 5.9 A.
The operational voltage range is 10.8 to 13.2 V DC. When using the
external power supply unit,
the so-called battery-protection circuit automatically
disables the internal battery in order to prevent damage.
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When a suitable power supply/battery charger is used,
it can be used to charge the battery simultaneously. For this purpose,
a separate contact is used in the connector and the battery.
The battery itself is a single-unit rechargable 12V accumulator
that is
installed behind a water-tight door at the front left
of the radio. In the battery compartment are
three contact pins,
marked J1, J2 and J3. The first pin (marked J1) is connected to the +12V
whilst J3 is connected to the negative terminal (-) of the battery.
The center pin (J2) is for charging the battery in-situ.
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Please note that the battery-protection circuit uses a latching
(bistable) relay. Once the internal battery is switched off, it will
remain disabled (even when the external power source is removed)
until the RESET POWER buttonon the front panel
– to the left of the MODE selector – is pressed.
Please note that when putting the radio in storage,
the power selector
at the front panel should be set to the OFF position (left).
When closing the radio,
an index stub
on the inside of the plastic top cover,
prevents it from being fitted when the power switch is not
in the correct position (OFF). The top cover is locked in place
by means of three latches at its sides.
When placed in the upright position,
the radio can be carried around by means of the
plastic grip at on of the short sides.
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The TAR-224 is a compact self-contained transceiver. The complete
radio is housed in a die-cast aluminium case that measures approx.
12 x 18.5 x 31 cm and weights just 6 kg. The case is fully waterproof,
and all controls, connectors and adjustments have watertight rubber gaskets.
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After loosening 10 torx bolts at the edges of the front panel, the entire
radio can be lifted out of the case.
The image on the right shows the interior of the radio with the front
panel facing down. At the left is the transmitter with the coils of the
Automatic Antenna Tuner clearly visible (the preotective cover is removed
here).
At the right is the receiver and (at the front) the internal wiring of
the various controls at the front panel.
The construction of the receiver is extremely complex. It is attached
to the front panel with just four bolts and can easily be removed.
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The receiver is connected to the rest of the radio with only
one 29-pin connector.
After removing the knobs and the four bolts from the front panel,
the entire receiver can be lifted from the connector
and, hence, the interior. The RX block consists of a series of
shielded units that are bolted together. They are wired together via
two (green) 14-pin connectors at the side.
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The image on the right shows the RX unit with the frequency scale
facing upwards. The 29-pin connector and the two 14-pins connectors
are visible at the left. A separate SMC connector is used for the
RF antenna input (at the front).
In order to accomodate the four frequency ranges, a complex construction
is used for the Antenna Matching unit, the RF pre-amplifier and the
Local Oscillator (LO). These three units are mounted side-by-side in
a single enclosure, with a common axle (attached to the BAND selector)
running through each compartment.
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As each of the three units has to be adjusted differently for each
frequency band, four different tuning sections are mounted around the
common axle in each compartment. When rotating the BAND-selector
at the front panel, the axle turns 90° with each step, selecting
a different section.
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The image on the right shows the interior of the three units.
The tuning section are clearly visible at the center of each compartment.
The rotation from the BAND-selector is carried over to the common axle
by means of a serial of
cogwheels and a chain belt
at the side of the receiver.
The tuning section is normally closed by a common metal plate that
covers the three sections (the cover is not shown here).
The signals from the HF pre-amplifier and the Local Oscillator (LO)
are fed to the IF-stage that is mounted
to the bottom of the receiver unit.
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The right half
of the TAR-224 contains the transmitter (TX), of which the
Automatic Antenna Tuner (ATT) is arguably the most interesting unit.
It is mounted in the front right corner
of the radio. It consists of a large adjustable capacitor and
a very special variable tuning coil.
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The image on the right shows the ATT after its protective
cover has been removed. At the left is the tuning coil.
It is connected via a cog wheel mechanism at the bottom,
to a synchronized rigged solid metal spool behind it.
At the front right is the electro-motor.
It drives the tuning mechanism at 1000 RPM.
Also connected to the mechanism is the large tuning capacitor
that is just visible behind the motor.
When enaging the ATT (by pulling the knob at the front panel),
the tuning capacitor and the coil are adjusted for
optimum SWR.
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A novel winding/unwinding mechanism is used
for the adjustment of the coil. When running, the wiring is moved from
the coil to the solid spool and vice versa. As a result the
induction of the coil is increased or decreased.
When starting the ATT, the mechanism is first fully wound back to the
reference position. It then runs forward and will stop when the
desired position is reached.
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Aftermarket modifications
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The original TAR-224 radios, as supplied by AVCO in 1970, had serious mechanical
and electrical problems. There were many contact problems with the
through-plated holes of the printed circuit boards (PCBs), badly soldered
ground planes and incorrectly stripped teflon wiring, which led to premature
failure of many units. Flaws in the mechanical design caused inconsistent
behaviour of certain controls, friction in the fragile tuning mechanism and
unnecessary wear of some parts [6].
By the time AVCO was ready to ship the units to the CIA, the company had
virtually run out of resources and failed to perform a proper final test.
In fact, quality control (QC) at AVCO had been so bad, that many
units were dead on arrival (DOA). In addition, the units that did work,
often exhibited electrical and mechanical faillures early in their live
when they were used in the field [6].
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The high faillure rate prompted the CIA to look for a company
that could repair, modify and improve the design, less than a year after
its introduction. The contract for this rework was awarded to WES Industries
in Dumfries (VA, USA), where all radios were modified during the course of 1972.
The rework required full disassembly of the radio and consisted of
modifications in the electronic circuits, repair of contact problems, repair
of badly stripped wiring, conformal coating of the PCBs and many mechanical
modifications.
The image on the right shows part of a hand-made drawing that was made
by WES engineers.
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The diagram below shows the pin numbering and connections of the connectors
at the front left of the TAR-224.
The two U-229 sockets (left) are identical [5].
They both are fully wired (A-F) in parallel. The other socket (right) is the
socket for the external power source. A suitable connector for the latter is
the Amphenol PT06A-8-3S, which is available from distributors like
Digi-Key (US).
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Pin
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Function
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Description
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A
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GND
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Ground (common wire)
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B
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SPK
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Speaker (separate, or part of handset/headset)
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C
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PTT
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Push-to-Talk switch (connects to ground)
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D
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MIC
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Microphone (separate or as part of handset)
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E
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KEY
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External (morse) key
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F
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+12V
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Power supply (output) for external burst encoder
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Pin
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Function
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Description
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A
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+12V
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Power supply (input)
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B
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GND
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Ground (common wire)
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C
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CHG
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Charge input (for internal battery)
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Pin
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Function
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Description
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J1
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+12V
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Power supply (input)
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J2
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CHG
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Charge input (for internal battery)
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J3
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GND
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Ground (common wire)
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Device Spy radio transceiver Manufacturer AVCO Corporation, Ohio (USA) Customer CIA, Western intelligence Years 1970 - 1986+ Power 12V DC Current 50 mA (RX), 4.3 A (TX) Dimensions 311 × 184 × 121 mm Weight 6 kg
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Type Superheterodyne Frequency 2 - 24 MHz Bands 4 (2-3.7 MHz, 3.7-6.9 MHz, 6.9-12.9 MHz, 12.9-24 MHz) Calibrator 500 kHz ± 0.01% Modulation AM, CW, SSB IF 455 kHz BFO ± 3 kHz Output ≤ 2 mW into 500Ω
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Frequency 2 - 24 MHz Bands 2 (1-12 MHz and 12-24 MHz) Modulation AM (phone), CW (morse) Output 20 W Antenna Single wire, 40 - 250 Ω Speed ≤ 300 wpm (with external keyer) Crystal CR-18/U (HC-6/U), parallel resonance, 32 pF 1
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Fundamental frequency in 2 - 12 MHz range, doubled in 12 - 24 MHz range.
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001 PA3ECT, Netherlands 106 Private collector 193 eBay 232 eBay 306 Private collector 315 eBay 328 eBay 359 eBay 382 Museum Gausdal 398 eBay 410 Private collector
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434 Crypto Museum 437 eBay, France 444 Pete McCollum 472 Receiver is chassis #444 484 Transmitter in chassis #444 521 Private collector, France 549 Private collector, NL 553 eBay 576 Private collector, Italy 583 eBay 600 Private collector, NL (TX only)
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New copy, scanned from original document, uploaded on 18 December 2022.
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Document kindly supplied by Norris Dale [6].
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New copy, scanned from original document, uploaded on 18 December 2022 [A].
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© Crypto Museum. Created: Wednesday 21 November 2012. Last changed: Sunday, 23 April 2023 - 10:05 CET.
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![Photograph by Elaine Blaisdell. Copyright 2009, The Journal [4]. Reproduced here with kind permission.](img/TerryRoberts.jpg)
![Snippet from the hand-made disassembly and modification drawings [D]](img/tar_drw.jpg)
