Rugged VHF/UHF Radio Transmitter


Model AT-9


The VLF/eentec AT-9 is a reliable, rugged, low power, field telemetry transmitter. The design features frequency synthesized operation over a 10Mhz range. Frequency band within a specific 10Mhz range must be specified at time of order. Minor frequency changes less than 100Khz, can be made by the user by changing dip switch positions.

Another useful feature of the AT-9 is the high efficiency, well-filtered internal power module that allows the user to adjust the output power from 100mW to 2W.

Typical transmission distance for a line -of-sight link is 100Km. Farther distances can be achieved with a 2W transmitter.

The AT-9 is completely compatible with Monitron radios and can be used as direct replacements in existing telemetry networks. In new networks, the unit transmits data from the PTSbg-x field telemetry instruments.

The unit is housed in an anodized aluminum case. It has a standard pin-out twist lock connector for power and audio input. The standard output connector is a “N” style with UHF or BNC optional. All connectors are wired to the Monitron standard.

Voltage input is between 12VDC to 14.4VDC. The AT-9 contains internal lightning protection circuits for the power and audio inputs.

Options and accessories include VHF frequency band, ¼ wave shorting stub for lightning protection on the RF line, external power supply if the unit is installed long distances from the field telemetry unit, and Yagi antennas.

  • Low Power
  • Rugged
  • Reliable
  • 100% Monitron compatible
  • Adjustable Output Power

Type: Synthesized NBFM

Frequency Ranges:
(Specify at time of order)

400-410.235 A band
410-420.235 B band
420-430.235 C band
430-440.235 D band
440-450.235 E band
450-460.235 F band
460-470.235 G band
Minimum Channel Spacing: 5 Khz
Frequency Stability: 2ppm, -30C to +60C
Output power: 100mW to 2W adjustable
Output Impedance: 50 ohm
Harmonics: -58dB below carrier
Spurious: -65dB or better
Audio Input Level: 1 Vrms for full deviation
Basic AT-9 Configuration The standard configuration is the specifications as stated, includes audio mating connector, calibration sheet and manual.

Specify at time of order

Lightning Protection Optional shorting stub ( consult factory)
Other Network Instruments

Field telemetry,
TC-70 or TC-80
Central Site,
Power supplies
Solar Systems
(Consult factory for correct configuration)

General Spares None

S Printer Friendly Format For Specifications

Modulation Frequency Response: 300 -3500Hz
Modulation: True FM, no pre-emphasis
Modulation Input: 2K ohm, single ended
Modulation Distortion: 0.1% or better
Deviation: ±5 KHz, internally adjustable with limiter
Dimensions: (inches) 7" x 4" x 2"
Operating Voltage: 12 V nominal (14.5 v MAX)
Case: Anodized aluminum
Operating Temperature Range: -30C to +60C
Operating Humidity: 0-95% RH (Non Condensing)
Controls: Power output (15turn pot)
Power and audio mating connector:

Pin A: Power,
Pin B Audio Input,
Pin C and D Ground

Antenna connection: Type "N" (others available)

Back to Top Specifications Subject to Change Without Notice
©eentec 2000, 2003, 2006