The R-4 covers: 3.5-4, 7-7.5, 14-14.5, 21-21.5 and 28.5-29 MHz plus ten 500 kHz crystal positions (with optional crystals). Four standard filters: 4.8 kHz, 2.4 kHz, 1.2 kHz and. 4 kHz which work in all modes. The dial accuracy is and impressive ±1 kHz. Features include: PBT, Line out, Crystal Calibrator (100 kHz), RF Gain, Mute Jack, Speaker Jack, Anti-Vox Jack, ¼ inch headphone jack and Dial Lamp.
This radio requires an external speaker. Transceive operation maybe obtained by adding the T-4 exciter or T-4X transmitter. 120/240 VAC 50-420 Hz 60 watts. 10.75 x 5.5 x 11.675 inches 16 lbs.