75A-4 and KWS-1

They were designed to operate using the then new single-sideband (SSB) voice modulation as well as CW and AM modes.

[2] Both radios used vacuum tubes and employed Collins innovations including mechanical filters and permeability tuned oscillators.

[a] The KWS-1 final amplifier use a pair of 4X150 power tubes and operated at a power input of one kilowatt, the maximum allowed under Federal Communications Commission (FCC) regulations at the time.

The transmitter appearance matched the receiver, but its high voltage power supply was packaged in a separate pedestal.

[3][4] In a 2006 review of the half-century-old 75A-4[5] Stu Cohen wrote "Performance under all but extremely crowded band conditions is still excellent, and a 75A-4 will hold its own against almost any receiver.