Radio Set AN/GRC-142
The AN/GRC-122 family consists of medium-power, vehicular mounted HF-SSB radio sets used primarily for RATT operations; however, they are capable of AM and SSB voice and CW operation. With the addition of a Navy standard 1 kW Radio Frequency Amplifier, AM-3924/URT and Antenna Coupler, AN/URA-38A, the AN/GRC-122 becomes an AN/GRC-122(V2). This modified version provides the capability for long-range communications of 3862 km (2400 mi). The AN/GRC-122 and AN/GRC-142 are both shelter mounted. Except for minor changes, all sets are similar and will replace the older family of RATT sets:

AN/GRC-122 has replaced AN/GRC-26D. AN/GRC-142 will replace AN/GRC-46. AN/VSC-2 has replaced AN/VSC-1. AN/VSC-3 will replace AN/VRC-29.

Secure FSK operation is possible when the above sets are used in conjunction with Electronic Teletypewriter Security Equipment, TSEC/KW-7. However, current tactical speech security equipment is not compatible with the AN/GRC-106; therefore, secure voice is not a mode of operation.)
(Source: FM 24-24, Radio & Radar Reference Data, May 1977)