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Brochures

Non-Directional Radio Beacons

- ND500- 125 W NDB Transmitter (Offshore & Airports)
- VR500-VR2000 - 500 W to 2,000W NDB Transmitters

Differential GPS Transmitters

- VRD750-VRD3000 - 750 W to 3,000 W DGPS Transmitters

NAVTEX

- ND 1250TT & ND 2500TT – 1.25 kW & 2.5 kW Navtex / MF Telegraph Transmitters

Antenna Tuning Units

- ATU500- 125 W ATU (Offshore & Airports)
- ATU-LP – 250 W ATU
- ATU-HP - 500 W to 3,000 W NDB ATU
- ATU-HP - 750 W to 3,000 W DGPS ATU

Antennas

- Helipad Wire Antenna (NSCL-HP)
- T-20 - Rated for up to 500 W average power
- T-35 - Rated for up to 2,000 W average power
- T-50 - Rated for up to 4,000 W average power

Accessories

- NRC1 and NRC2 - Remote Control Unit (Master and Slave)
- NRB4 and NLA/2- Remote Monitor Alarm and Loop Antenna
- SPU - Surge Protection Unit
- ECMP1 - Extended Control/Monitor Panel

Specifications (available if seperate from brochure)

Non-Directional Radio Beacons

- VR500-VR2000 - 500 W to 2,000 W NDB Transmitters

Differential GPS Transmitters

- VRD750-VRD3000 - 750 W to 3,000 W DGPS Transmitters

NAVTEX

- ND 1250TT & ND 2500TT – 1.25 kW & 2.5 kW Navtex / MF Telegraph Transmitters

Accessories

- Helipad Wire Antenna (NSCL-HP)

White Papers

High Accuracy Nationwide Differential Global Positioning System (HA-NDGPS) 
Lightning Protection Guidelines
Recommendations for Transmitter Site Preparation

Improving the Performance of LF/MF Transmitter Installations 
The United States Coast Guard operates a nationwide network of medium frequency transmitters to augment the GPS System by supplying correctional data to localized users. Operating in the frequency band 282 325 kHz at a power level of 1 kW, they are required to provide a field strength of 75 micro volts per meter at a range of 200 kilometers. This technical paper addresses a specific problem, whereby variations in the antenna system cause variations of the field strength at the specified range.

Development of an Antenna Coupler that Fully Compensates the Deficiencies of Electrically Short LF/MF Antennas
Advances in semiconductor technology have made today’s transmitters such as non-directional radiobeacons and differential GPS transmitters much more efficient than their predecessors. The subsequent reduction in their physical size has made them significantly more susceptible to the effects of mismatch of their terminating impedance that results in increased heat dissipation in their final amplifiers. This paper describes the development of an Antenna Tuning Unit, which provides automatic adjustment of both the loading coil inductance and the resistive matching network so that an acceptable transmitter terminating impedance is maintained over wide variations of antenna characteristics. Utilization of this technology can significantly reduce the field strength variations that are currently being experienced with both radio beacon and DGPS transmission systems. This could allow a far higher confidence level in meeting the required range and signal availability.

Comparison of a Southern Avionics Diamond Portable Antenna with a New Design Proposed by Nautel
The Nautel design has twice the RR value of the SAC antenna. As the radiated power is proportional to the radiation resistance (PR=Ia2 x RR), it can be seen that twice the radiated power can be achieved for the same antenna current with the Nautel design. The SAC transmitter has an efficiency of 40%, compared to 70% for a Nautel transmitter. Hence, combining this greater transmitter efficiency with the increased efficiency of the Nautel antenna, a 3.5:1 overall advantage is achieved

Engineering the All - Weather Antenna Tuning Unit for NDGPS Applications
Published in the U.S. Coast Guard Engineering, Electronics & Logistics Quarterly, Winter 2006 (Used with Permission)

Using the Optional Resistor Bank to Improve the Antenna Bandwidth
The height of a typical NDB antenna is much shorter than the ideal value.  As a result, the antenna input impedance appears as a small resistance in series with a high capacitive reactance.