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STR-1800 Multi-Mode UHF/VHF Mobile Data Radio
Flexible Solution for Reliable Narrowband Communications


  • Long Range VHF/UHF Data Telemetry Links
  • Distributed Power Control Systems
  • Remote Monitoring of Oil/Gas, Water/Wastewater Stations
  • SCADA Primary and Relay Stations
  • Small / Micro / Nano / Cube Sat TT&C Links
  • UAV, RPV and Similar Remote Control and Monitoring
  • Supports ARTM PCM/FM and SOQPSK

The STR-1800 family of VHF/UHF transceivers represent a MIL-spec ruggedized land mobile solution for applications requiring high power (up to 45 Watts) as well as high reliability. The ultra-compact size of these radios make them ideal for a wide variety of applications. The STR-1800 Multi-Mode Data Radio is a new generation of the STR line of mobile data radios that provides increased performance and functionality for deployment in legacy 25 kHz and newer 12.5 kHz and 6.25 kHz channels subject to FCC narrowbanding mandates.

The STR-1800 provides one of the fastest transmit turn-on and receive recovery times of similar high power products, making it an ideal choice for time-critical data telemetry applications. Supporting 25 kHz, 12.5 Khz, or 6.25 kHz channel spacing, the radio supports data speeds up to 19200 baud.

The main chassis is one-piece, die-cast aluminum, providing a product which is resistant to impact while also being extremely effective at heat dissipation. The thermal design provides for a high ratio of transmit to receive duty cycles. Up to 32 Configuration Profiles can be stored with user-defined link names and recalled with a single command, simplifying fast and accurate configuration changes.

A front panel DB-9 and DB-25 connectors provide all digital and analog user interfaces including those required for programming radio frequencies, bandwidths, and transmit power levels, as well as audio input/output, push to talk, and active channel selection. Rear panel connections are provided for the RF interface as well as primary power (+12 VDC).

SRI is a leading supplier of advanced products for defense, civil, and commercial satellite, aircraft and missile test range, and test & measurement data communications and telemetry applications and has been able to leverage knowledge and experience in these markets to apply proven, reliable military SOQPSK-TG telemetry transmission techniques to commercial Land Mobile Radio (LMR) data communications. Previous industry practices relied on variations of FSK and GMSK techniques to meet narrowbanding 6.25 kHz channel requirements. This breakthrough significantly improves link reliability and performance for applications requiring extended operating ranges over difficult terrain.

The radio features an output power level up to 45 Watts and is available for domestic and most international uses supporting analog and digital signals. Various models of the product family cover most commonly utilized VHF or UHF frequency bands. Different versions of the radio's are certified through the FCC, IC, ASA, and ETSI.

Specifications: PDF

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Key Features

  • Multiple Waveforms for 6.25, 12.5, and 25 kHz Channels
  • Multi-Mode Analog and Digital Transceiver
  • Embedded Audio Tone FM and Digital Modem
  • Supports ARTM Tier 0 (PCM/FM) and Tier 1 (SOQPSK)
  • Field Upgradable for Enhanced Performance
  • Specifications: PDF


Model STR-1800 Multi-Mode UHF/VHF Mobile Data Radio

RF Specifications

Frequency Range:

STR-1810 : 136 to 174 MHz

STR-1820 : 400 to 470 MHz

STR-1830 : 400 to 470 MHz (ETSI/Other Countries)

STR-1835 : 450 to 520 MHz (ASA)

Consult Factory for Other Frequency Bands

Channel Spacing: 25/12.5/6.25 kHz (UHF); 25/12.5 kHz (VHF)

Preset Channels: 8

Stability: +/- 0.0001% of Fc

Duty Cycle:

Capable of 30 seconds continuous transmit or 25% continuous transmit/receive duty cycle


Various models available for:





type certification. Contact factory for further information


Analog Modulation

Type: FM (V.23 FSK)


Rated Deviation:

+/- 5 kHz for 25 kHz Spacing

+/- 2.5 kHz for 12.5 kHz Spacing


Digital Modulation


Data Rates: 1200, 4800 bps

Occupied Bandwidth: 25 kHz

12.5, 6.25 kHz (FCC Narrowband Compliant)


Interface Conversion

User In/Output Mode: V.23 FSK, RS-422

Over-The-Air Mode: V.23 FSK, SOQPSK


Transmit Characteristics

Output Power: Selectable between 5, 25, and 40 Watts

Output Protection:

Operating into a 10:1 VSWR of any phase angle will not damage the transceiver

Spurious/Harmonic Output: -70 dB below rated power

Modulation Sensitivity:

Adjustable from 50 mvolt RMS audio input signal for 60% of rated deviation

Frequency Response:

Flat from 300 to 3000 Hz (no pre-emphasis)

Turn-on Time:

Within 25 msec (UHF) or 40 msec (VHF) of keying, radio reaches 90% of rated output power.

Output SNR: 30 dB minimum fully modulated

Audio Input Impedance: 50 Ohm


Receive Characteristics

Sensitivity: 0.25 uV (12 dB SINAD) typical

Dynamic Range:

0 to -100 dBm for 23 dB SINAD (1 kHz Tone at 60% dev)

Spurious/Image Rejection: 70 dB minimum

Intermodulation: 70 dB minimum


75 dB typical for 25 kHz spacing

65 dB typical for 12.5 kHz spacing

50 dB typical for 6.25 kHz spacing

Recovery Time: 30 msec from removal of key signal

Audio Output:

Adjustable from 60% dev for 1 V p-p output into 600 ohm resistive load for 1 kHz input signal

Frequency Response:

Flat from 300 to 3000 Hz (no de-emphasis)

Overload Protection:

A +28 dBm input continuous applied to input will not cause any permanent damage


Programming Control Specifications

Platform: Windows compatible PC

Preset Channel Controls:



Output Power Levels


Special control cable from serial COM port to STR-17xx


Other Specifications

Chassis: ~ 2" High, ~ 6" Wide, and ~ 7" Deep

Weight: 3 lbs


1 UHF for RF Input/Output

1 25 Pin D (Front Panel) for:

Programming Interface

Audio/Data Input/Output

Preset Channel Selection


1 9 Pin D (Front Panel) for:

Programming Interface

Digital Data Input/Output

Primary Power

13.6 VDC ± 15% ( transmit 12.5 A, receive 0.7 A)

MTBF: 25,000 Hours

Operator Adjustments: None


-30° TO 60° C (Operational and Storage)


2 g rms 5 Hz-300 Hz sinusoidal, 3 axes, continuous


10 g half sine, 15 msec; 3 axes


Up to 100% ‘non-condensing’


10,000 feet operating and 40,00 feet non-operating




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