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SINCGARS
  
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RT-1439
SINCGARS non-ICOM Radio

RT-1439/VRC is a military non-ICOM VHF/FM ECCM-capable transceiver for the 30-87.975 MHz range, developed and manufactured around 1988 by ITT. It is an early member of the SINCGARS family and does not have built-in voice encryption [1]. Instead an external KY-57 voice encryptor is required. It supports (slow) Frequency Hopping (FH) at 100 hops/s and is backward compatible with Single Channel radio devices, like AN/PRC-77 and the AN/VRC-12 from the Vietnam era.

At the centre of the front panel is the keyboard and the red LED display. The keypad is used for the entry of channel numbers and the selection of frequency hopping tables.

To the left of the keypad are the channel and mode selectors. The rig supports single channel operation (SC) as well as frequency hopping (FH). Six preset radio channels can be selected directly, others are entered on the keypad. Also on the left is the power selection, allowing the choice between low power (LO), medium (M), high (HI) and an external power amplifier (PA).
  

To the right of the keypad are two audio connectors. In normal use these are used for the connection of a handset and/or a secure communications unit (ICOM) like the KY-75. The upper connector is also used for an ECCM fill device, such as the MX-18290 or CYZ-10.

RT-1439 left angle view
RT-1439 right angle view
RT-1439 front angle view
Front panel
Rear panel
RT-1439 straight up
Backup battery compartment at the bottom
Backup battery
Front panel of the RT-1439, showing the two audio connectors with their combined functions.
AUDIO/FILL and AUDIO/DATA connectors on the front panel of the RT-1439
Setting the serial baud rate
27-pin system connector
55-pin socket for connection of a COMSEC device
RT-1439 with CY-8523 battery case installed at the rear
BB-940 battery installed in battery case
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RT-1439 left angle view
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RT-1439 right angle view
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RT-1439 front angle view
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Front panel
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Rear panel
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RT-1439 straight up
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Backup battery compartment at the bottom
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Backup battery
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Front panel of the RT-1439, showing the two audio connectors with their combined functions.
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AUDIO/FILL and AUDIO/DATA connectors on the front panel of the RT-1439
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Setting the serial baud rate
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27-pin system connector
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55-pin socket for connection of a COMSEC device
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RT-1439 with CY-8523 battery case installed at the rear
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BB-940 battery installed in battery case

Features
The image below provides an overview of the controls and connections of the RT-1439. The unit is powered by a 10.5 to 15.5 V/DC power source, such a 12V battery, that must be installed in an adapter that is connected to the system connector (P1) at the rear. All controls are at the front panel. At the centre is a LED display and a 16-button keypad for user I/O. The other controls are explained below. At the front panel are also 4 receptacles: a BNC socket for connection of the antenna (ANT), two audio plugs (AUD/FILL and AUD/DATA) and one for retransmission (RXMT).


At the right side is a circular 55-pin socket (J5) for connection of a COMSEC device such as the KY-57 or KY-99. Note that a special interconnection cable is needed for either of these devices. The unit is switched ON with the MODE-selector, whic is further explained below.

MODE selector
  • OFF
    Power off
  • TST
    Test
  • SQ/ON
    Operation with CTCSS squelch
  • SQ/OFF
    Operation without CTCSS squelch
  • RXMT
    Retransmit mode (operation as repeater)
Frequency Hopping Mode
  • SC
    Single Channel
  • FH
    Frequency Hopping mode
  • FH/M
    ?
RF output
  • LO
    500 µW
  • M
    160 mW
  • HI
    4 W
  • PA
    50 W (only when PA module is fitted)
Channel selection
  • MAN
    Manual frequency entry (via display and keypad)
  • 1-6
    Preset 1 to 6
  • CUE
    ?
ECCM
The RT-1439 has built-in ECCM provisions in the form of a (slow) Frequency Hopping (FH) capa­bility with a hop-rate of 100 hops/second. Note that FH can only be used if at least one valid hop-set and a valid Transmission Security Key (TSK) have been loaded into the device by means of an MX-18290 or CYZ-10 fill device. Frequency Hopping serves the following purposes:

  1. Jamming resistance
  2. Low propability of intercept
  3. Low probability of direction finding
COMSEC
When additional Communications Security (COMSEC) is required, an external encryption device must be connected to the RT-1439. The first voice encryption device that was available when the RT-1439 was released, was KY-57 (VINSON). It offers wideband encryption over a 25 kHz radio channel using CVSD modulation at 16 Kb/s. For encryption it uses the secret SAVILLE algorithm, jointly developed in the late 1960s bu GCHQ and NSA. The diagram below shows the full setup with a KY-57. Later SINCGARS radios had built-in KY-57 functionality, known as SINCGARS ICOM.


In 1994, KY-57 was succeeded by KY-99 (ANDVT), which offers wideband (25 kHz) as well as narrow­band (3 kHz) encryption for both voice and data. In wideband-mode the KY-99 is com­pa­tible with VINSON devices like the KY-57. The diagram below shows the setup with KY-99.


Note that the standard MX-18290 fill device — used for loading hop-sets and TSKs — cannot be used for loading Traffic Encryption Keys (TEKs) into the KY-57 or KY-99. KEKs must be loaded with a separate fill device like the KYK-13. Both fill devices (MX-18290 and KYK-13) were later combined into the CYZ-10, which can handle all ECCM and COMSEC material.


Parts
RT-1439 SINCGARS VHF/FM radio transceiver
KY-57 (VINSON) wideband voice encryptor
KY-99 (ANDVT) narrowband voice and data encryptor
MX-18290 ECCM fill device for Frequency Hopping
KYK-13 crypto fill device
AN/CYZ-10 Data Transfer Device
Military handset H-250/U with U-229 connector (or equivalent)
M-80C/U noise-cancelling microphone
Lightweight headset
External active loudspeaker
Backup battery BA-5372 or equivalent
CY-8523 Battery Box
Main 12V battery BA-5590 or equivalent
Improvised battery charger
Power Amplifier
PA
Radio transceiver   RT-1439
At the heart of this SINCGARS system is the RT-1439, which is a non-ICOM radio with ECCM features. It features slow frequency hopping (FH) at a rate of 100 hops/s. Hop-sets and TSKs are loaded with an MX-18290 or CYZ-10 fill device.

For COMSEC, a separate KY-57 (VINSON) voice encryptor must be connected. When installed, it needs a different fill device, auch as the KYK-13.

  

Voice encryptor   KY-57
When the RT-1439 was released in 1988, it did not have buil-in voice encryption. Instead it had to be used with the external KY-57 secure voice module, that was inheriterd from the PRC-77 era. Later SINCGARS ICOM radios, such as the RT-1523, had built-in KY-57 functionaly.

Note that a separate fill device, such as the KYK-13 is needed to load the TEKs into the KY-57. The KY-57 was superceeded in 1994 by the back­ward compatible KY-99 (see below), which can also encrypt digital data traffic.

 More information

  

Voice and data encryptor   KY-99
In 1994, the wideband KY-57 (VINSON) was superceeded by the narrowband KY-99 (ANDVT). KY-99 was more suitable for use on narrowband HF channels (3 kHz), but was fully backward compatible with wideband KY-57 (25 kHz).

Like KY-57, the KY-99 uses the highly secret SAVILLE encryption allgorithm. Note that a separate fill device, such as the KYK-13 is needed to load the TEKs into the KY-99.

 More information

  

ECCM FILL   MX-18290
Frequency Happing tables (FH-sets or hop-sets) and Transmission Security Keys (TSKs) have to be loaded into the RT-1439 by means of the dedicated MX-18290 fill device shown in the image on the right.

This device is not suitable for loading crypto keys (TEKs) into the KY-57 voice encryption unit.

 More information

  

Crypto FILL   KYK-13
When using the external KY-57 voice encryptor for COMSEC, the required Traffic Encryption Keys (TEKs) have to be loaded into the KY-57 by means of a fill device that can handle 128-bit SAVILLE keys, such as the KYK-13 key transfer device shown in the image on the right.

Note that the KYK-13 cannot be used to load FH-data into the RT-1439. That can only be done with the MX-18290 or CYZ-10 (see below).

 More information

  

Crypto FILL   CYZ-10
In 1993, the functionaly of the MX-18290 and the KYK-13 fill devices was combined into a new device — the CYZ-10.

The CYZ-10 is a more universal Data Transfer Device (DTD) that can handle various kinds of cryptographic keys of arbitrary lengths, as well has frequency hopping data.

 More information

  

Handset   H-250/U
For voice communication, the RT-1439 was usually equipped with a regualar military handset, such as the H-250 shown in the image on the right. There are many variants of this handset, from a variety of manufacturers.

In some situations, such as aboard an armoured vehicle, the use of separate headphones and microphones might be more appropriate.

  

Microphone   M-80C/U
In noisy environments and in situations where the use of a handset would not be practicle, a noice-cancelling handheld microphone was issued, such as the M-80 shown in the image on the right.

In this case, separate headphones or speakers must be used as well.

  

Headphones   H-251/U
In noisy environments, such as aboard an armoured vehicle, headphones might be more appropriate than a handset.

The image on the right shows a lightweight Astrocom H-251/U that was frequently used with SINCGARS equipment.
  

Speaker
Apart from handsets, most behicles are equipped with one or more speakers, such as the LS-671 active loudspeaker shown in the image on the right. It has a volume control and an U-229 receptacle for connection of a micro­phone or handset. Such speakers can be fitted anywhere in the interior of the vehicle, but require special wiring.

A good alternative might be the LS-454/U, which is a passive speaker that can be connected to one of the AUDIO receptacles of the radio and does not require special wiring.

  

Backup battery   BA-5372
The FH-sets and TSKs are retained in the static memory of the RT-1439 by means of a small 6V battery that is installed behind a lid at the bot­tom of the radio. Under normal circumstances, this battery should be replaced once a year.

In practice, these batteries often last much longer than one year. Noe that the same type of battery is used to power the MX-18290 and KYK-13 fill devices. The backup battery is also known as the Hold Up Battery (HUB).

 More information

  

Battery   BA-5590
The RT-1439 can be powered in a number of ways. When used in a panpack configuration, it was usually powered by a BA-5590 battery or equivalent, such as the rechargeable BB-490 shown in the image on the right.

The battery was installed in the CY-8523 battery box that had to be fitted to the rear of the radio.

 More information

  

Battery box   CY-8523
When batteries are used, they have to be in­stalled inside the CY-8523 battery box shown in the image on the right. The box is attached to the rear of the RT-1439 with four spring-loaded latches – two at either side. At the rear end is a lid that is held in place with another two latches. The battery is located behind this lid.

The battery box also holds two wire terminals that can be used to connect a tone-based Remote Control Unit (RCU).

  

Charger
When rechargeable batteries are used — typically with model numbers starting with 'BB' — a battery charger has to be used, that is suitable for the chemistry used in the selected battery. A variety of stationary, mobile and portable chargers is available.

The image on the right shows an improvised battery charger that was made from the internals of an unknown charger for the BB-490.

  

Antenna
We are currently unable to show a picture of the original antenna, as it is missing from the setup in our collection.   

Power Amplifier   AM-7238
We are currently unable to show a picture of the power amplifier (PA) upgrade, as it is missing from the setup in our collection.   

H-250/U handset with coiled cable
H-250/U handset
Right angle view
Rear view
Power terminals
Multi-connector (mates with receptacle at the rear of the RT-1439)
Interior
BB-940 battery installed in battery case
BB-309 battery
Rear panel with LCD readouts
Female connector
Improvised battery charger
Battery charger
Handheld noise-cancelling microphone
M-80C/U microhone
Lightweight headset with U-229 connector (without microphone)
LS-671/VRS external loudspeaker
Right angle view
Left angle view
Front view
LS-454/U speaker (without controls)
RT-1439 with CY-8523 battery case installed at the rear
BB-940 battery installed in battery case
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H-250/U handset with coiled cable
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H-250/U handset
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Right angle view
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Rear view
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Power terminals
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Multi-connector (mates with receptacle at the rear of the RT-1439)
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Interior
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BB-940 battery installed in battery case
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BB-309 battery
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Rear panel with LCD readouts
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Female connector
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Improvised battery charger
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Battery charger
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Handheld noise-cancelling microphone
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M-80C/U microhone
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Lightweight headset with U-229 connector (without microphone)
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LS-671/VRS external loudspeaker
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Right angle view
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Left angle view
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Front view
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LS-454/U speaker (without controls)
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RT-1439 with CY-8523 battery case installed at the rear
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BB-940 battery installed in battery case

Connections
Audio
At the top right of the front panel are two U-229 receptacles marked AUD. Either one can be used for the connection of a handset, headset, microphone or speaker. The upper one can also be used for connection of a fill device, such as the MX-18290 or CYZ-10. The lower one can also be used for connection of a data device, such as a message terminal. Below is the pinout for audio devices, when looking into the receptacle.  More

  1. GND
    Ground
  2. SPK
    Speaker
  3. PTT
    Push-to-Talk
  4. MIC
    Microphone
  5. ?
  6. ?
Data
The lower U-229 socket can also be used for the connection of a DATA device, such as a personal computer or a message terminal. In that case, the pinout is as shown below.  More

  1. GND
    Ground
  2. RXD
    Data from radio
  3. PTT
    Grounded when transmitting
  4. CLK
    Clock out (in synchronous mode)
  5. DIG
    Digital data mode select
  6. TXD
    Data into radio
FILL
The upper AUDIO receptacle can also be used for connection of a fill device, such as the MX-18290 or CYZ-10.  More

  1. GND
    Ground
  2. SWG
    Switched ground
  3. ACK
    Fill request acknowledgment
  4. DATA
    Fill data into KY-99
  5. CLK
    Fill clock into KY-99
  6. ?
RXMT
At the bottom left of the front panel is a U-229 connec­tor marked RXMT. It is used for connection to another RT-1439 to allow repeater operation (retransmit). Note that the two transceivers must be connected with a cross-over cable (not a 1:1 cable). This means that wires D/B and C/E must be crossed. Wires A and F are wired straight through. Below is the pinout of this connector.

  1. GND
    Ground
  2. SO
    Signal Out
  3. CI
    Control In
  4. SI
    Signal In
  5. CO
    Control Out
  6. ADS
    A/D Select

Specifications
  • Device
    Military VHF radio set
  • Purpose
    Voice and data communication with ECCM
  • Model
    RT-1439
  • Family
    SINCGARS
  • Country
    USA
  • Year
    1988
  • Manufacturer
    ITT, General Dynamics
  • Predecessor
    PRC-25, PRC-77, VRC-12
  • Frequency
    30 to 87.975 MHz
  • Channels
    2320
  • Spacing
    25 kHz
  • Waveform
    FM
  • Operation
    Single Channel (SC) or Frequency Hopping (FH)
  • Encryption
    External: KY-57, KY-99
  • FH
    100 hops/s (slow hopping)
  • FILL
    DS-102, MX-19290
  • Squelsh
    CTCSS (150 Hz)
  • Output
    500 µW, 160 mW, 4W (50W with external AM-7238 power amplifier)
  • Data
    73, 150,300, 600, 1200, 2400, 4800, 1600 baud
    AD1, AD2 (TACFIRE)
  • Power
    10.5 to 15.5V (typically 12V)
  • Battery
    12V, BA-5590 (or equivalent)
  • Backup
    6V, BA-5372 (or equivalent)
  • Dimensions
    371 × 236 × 84 mm
  • Weight
    8.5 kg
  • Price
    US$ 6,500 (est.)
  • Quantity
    16,475
Documentation
  1. TM 11-5820-890-30
    Technical Manual, Intermediate (direct support) maintenance

    Department of the Army, 1 March 1988.
References
  1. Brooke Clarke, RT-1439 SINCGARS
    2005-2022. Visited 27 April 2024.

  2. Wikipedia, SINCGARS
    Visited 2 May 2024
Further information
Other websites
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Crypto Museum. Last changed: Sunday, 12 May 2024 - 11:10 CET.
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