Radio Set AN/GRC-26 The "ANGRY 26" was a shelter mounted HF RTTY communications system. It could operate from mobile, moveable, and fixed locations. (The SCR-399 mobile HF radio set, used extensively in WWII, was modernized and equipped with a teletype apparatus. The new model with this modernization was designated AN/GRC-26. It was accepted for service in 1950.) (Source: TM 11-264, Radio Set AN/GRC-26)