URC-64 and URC-4 Aircrew Rescue Radios

The AN/URC-64 radio was issued to USAF aircrews as a replacement for the AN/URC-10. It was apparently only issued within the USAF as the Navy and Army seemed to have other equipment for the task as the technology for this type of radio was evolving rapidly.
(Now is not a good time to learn Morse Code!)

The radio is UHF only, using 4 selectable channels with AM Voice, MCW Morse Code or a sawtooth chirp signal (Tone) as a homing beacon. Transmitter output was 200 milliwatts, plenty for long distance LOS comms to an aircraft at altitude or one overhead.

AN/URC-64 Instructions

The radios were all solid state and held a replaceable 13.5 volt BA-1113 battery. They came with an earplug that snapped into terminals on the bottom. The microphone also doubled as a speaker.

To operate the radio, the antenna is pulled out to full extension, thus actuating the power switch. Choose the desired mode and frequency and operate. Simple. As it should be.

The radio includes a little analog meter that indicated modulation, power output as well as a battery test function. The channel selector could be locked in place; a volume control was included.

The set would have been carried as part of aircrew survival equipment along with other items from the bail-out kits. They are fairly small and self-contained.

URC-64 Essential Survival Gear

Make sure your compass does not indicate the speaker magnet as “North”.

I would not be surprised if radios such as these found their way into small ground units for supporting their internal comms (hopefully on non-emergency frequencies). It would fill the bill in the absence of a dedicated set available at the time. They would be handy. Stuff happens.

My examples were refurbished by the Sacramento Air Logistics Center in 1989 and painted with a distinctive yellow back panel. This was to denote use in training only; the radios were re-tagged as AN/URC-64T versions that were crystalled with 4 non-emergency training frequencies.

Yes, of course I broke the seal!

These radios were rebuilt with crystals that were not on the standard UHF Emergency frequencies. Those emergency frequencies included 243.0 mc and probably 282.8 mc, another SAR channel in use at the time in deployed radios. Another one that might make sense is 277.8 mc, the standard Navy “Fleet Common”, in case you needed Navy help! Or possibly frequencies used by the owners squadron, however that would take some work to get and install special crystals and then tune them up.

It took some effort to convert operational sets to the “training” variant.  With a unique set of crystals, a dedicated, new NSN and even nomenclature and paint job.  There must have been a big need for these in SERE training schools.  Well done.

Today it would be a simple matter to re-crystal and re-tune one of these radios to operate on the 220 mc Ham Bands.

AN/URC-64T with Training Frequencies installed

The URC-64 was first fielded in 1964 when it replaced the URC-10. They were widely available during the Vietnam war, notably by Lt. Col. Iceal Hambleton a USAF officer who ejected from a damaged EB-66 EW aircraft just north of the DMZ. Call Sign BAT 21 Bravo, his rescue was the subject of the movie “BAT 21”. When he was asked what was the most important piece of equipment he had: “The URC-64”.
The AN/URC-4 Aircrew rescue radio

For a downed aircrew, short range Ground-Air communications would be essential of course. Earlier than the URC-64 it was the URC-4 VHF/UHF radio that would have been the local ground-air set in the 1950-60’s. Its 35 milliwatt transmitter could be heard nearly 100 miles away by a high altitude aircraft with otherwise line-of-sight to the radio. The receiver is a simple Super Regenerative type.

URC-4 Aircrew Rescue Radio

Above: The URC-4 with the horizontal dipole antenna configured in the collapsed position for UHF communications on the 243 mc Guard freq. It could also operate on the standard VHF emergency frequency 121.5 mc. In that case, the dipole elements would be pulled out to full extent for the lower frequency. The VHF/UHF band switch is on the side of the radio. Note that 243 mc is the second harmonic of 121.5 mc. Simplifies the circuitry.

URC-4 VHF/UHF Band Switch

This 8 vacuum tube transceiver was first fielded around 1950 and saw service in Korea, and through the Vietnam war aboard practically everything that could fly. It was eventually replaced sequentially by the AN/URC-11, AN/URC-64, AN/URC-68, AN/PRC-90 and others in the series.

The URC-4/RT-159 requires an external Mercury battery delivering 1.3 Volts and 136 Volts. It is connected by a short cable intended to keep the weight split between the 2 sides of an aircrew E-1 survival vest or similar.

The external BA-1264 battery contained nearly a pound of Mercury (Reference 83). Internet Folklore has it that the radio and battery “kept going” after the opening shock of the parachute caused them to tear through the bottom of the pockets of the survival equipment vests.

URC-4 and Signal Mirror

The radio mode switch could be “Locked” in a Receive, Trans (voice) or a continuous Tone function. This Tone, when selected, would be a beacon for an aircraft equipped with a homing system allowing the pilot to locate the crew. For example the Strategic Air Command “over the pole” bomber crews had these radios which would enable rescue/pickup by C-47’s equipped with the ARA-25 UHF directional antenna mounted on the nose.

On 23 August 1950 the USAF SAC had established the 8th Air Rescue Squadron specifically for this aircrew recovery mission. They were equipped with ski-capable SC-47 aircraft that could land on frozen tundra or the polar icecap. More info here: SAC Bomber Crew recovery with the RS-6/URC-4

This example may have seen service in the 8th Air Rescue Squadron.

AN/URC-4 rear panel

“ARS” looks to be stenciled on the back. Set 33 apparently. That clip enables the battery to be physically mounted on the back of the radio, the power interconnect cord was still required.

After landing the crewmen would fire up their  RS-6 HF CW radio to call for a pickup….Then, once seen or heard, the crew would switch from Tone beacon to Voice to coordinate and designate an LZ for subsequent pickup.

URC-4 Operator Instructions

Francis Gary Powers had one in his U-2. The Soviets had other ideas about his “pick up”.