Military Collector Group Post (Mar.21/2001)



I've long searched for information about the early testing, and use, of the Hughes HC-162(commercial model number for the PRC-74), but until
recently I've found virtually nothing except for some vague references to a SSB radio with nothing specific being named. Over the last few weeks
I've been doing some very intense Internet searching while trying to dig up the slightest little tidbit of information on the OPS series radios,
some interesting items have turned up instead.


 Memoirs of a Sneaky Pete
© 1997 Donald E. Valentine
exerts from 5th Group Vietnam 1963-Dec 1965

Testing of the GRA-71 & ? ca 1963:

[Our radio team went out twice. Our first trip was to Fayetteville, Tennessee for about a week or ten days, where we got rooms in a local downtown hotel. We set up our radio in one of our rooms and proceeded to communicate with Fort Bragg.

We were testing the "burst device" and "code machines" that were made to use with the burst device. There were two code machines. One of the code machines was made for use by anyone, no knowledge of morse code was required. It had a dial, a selector, and a little crank like the ones on
hole punches. On the face of the dial were all of the characters in the alphabet, numbers from 0 - 9, and "a blank space" for use between words.  You attached this tiny machine to a small tape cassette, selected a letter, a number or a space and hit the crank. The code machine
electromagnetically placed that signal onto the tape in morse code. When you had went through the entire message like that, you then connected the tape to the burst device and the burst device to your transmitter and when it was time to transmit the message, you just pushed a button and the message was transmitted at 300 words per minute.

The other code machine required a knowledge of morse code or at least a card showing the morse code for letters and numbers. It was the same size as the other encoder, but it did not have a crank and it did not have a dial. It only had three buttons. A "dot" button, a "dash" button, and a "space" button.

The dial-faced encoder was the only one worth having. If that one works, why in hell bother with the one that required a knowledge of morse code?  That tiny device, if it worked, would totally eliminate the need to train special forces troops or espionage agents in morse code. They only needed to know how to assemble and use the radio equipment. Unfortunately, neither method worked satisfactory.

When we completed our test there, the other guys headed back to Fort Bragg in the jeep and took the radio equipment with them................

........Harry Pee And I discovered that the base station at Fort Bragg never managed to decode a single message from the field. Part of the problem were the code machines. The code machines werenít putting the correct signal on the tape or they werenít putting any signal on the tape. There was no way for the person using the coder to know it was malfunctioning. Also successfully receiving the signal proved to be more difficult than first thought. The signal had to be taped and then slowed down from 300 words per minute to 15 - 20 words per minute so the receiving radioman could copy it. The burst device flunked the field test and never became standard issue for SF. That was too bad, it was a good idea.]

HT-1 & PRC-10 Use, Vietnam ca 1964:

[On our first operation we worked out of our base camp because the area of operations was near Nha Trang. Our officers planned the operation and were about to infiltrate the team before I even knew that there was an operation underway that I had to support. No one informed me about the operation, they just showed up wanting radio equipment. "This is a hell of a way to run a railroad," I said to myself. As it turned out, the staff officers had decided to use HT1s on the ground and a Prick Ten
[AN/PRC-10] in the chopper. I warned them, "One radio set is AM and the other is FM. It might work and it might not. If it did work it would be at short distances only." They went with their plan anyway and fortunately, the radios worked okay, but there could have been a tragedy on that operation.]

HC-162(PRC-74) Testing,

[Delta communications was responsible for combat testing proposed SF radio equipment. We had the only six prototypes of the HC-162 radio sets.  The HC-162 was a portable, Single Side Band radio with Morse Code and voice capability. It had a re-chargeable, wet-cell battery, a doublet antenna, a whip antenna, a head set, and a telegraphic key that is mounted on a clip that clamps onto your thigh for field use. The transceiver and battery weighed about 50 pounds. The battery was the biggest pain in the ass. It seemed to weigh a ton and always needed repairing, cleaning or re-charging. The battery weighed more than the transceiver.

Periodically we would set up a 162 at our base camp at Nha Trang and test it. We would use the fold-up whip antenna which was about eight feet long as I recall and a doublet antenna strung only three feet above the ground for these tests. We called the US Air Force control tower at Bangkok,
Thailand and Clark Air Base in the Philippines. Our signal was normally loud and clear. Just in case you donít know anything about radios, thatís pretty damn good for a man-portable, high frequency radio set that only has a 12 watt output. When we took those radios to the field we had to rig a demo charge to each set because they were classified TOP SECRET. That just added more damn weight. Besides, every damn thing we did was classified TOP SECRET and I didnít have a charge tied to my ass. Eventually, the RT guys stopped attaching demolitions to the radios.................

.............We recommended several changes for the HC-162 radio set.  Some changes that I recall were a lightweight, disposable dry-cell
battery for field use; a power converter/transformer for 110 volt ac, 220 volt ac, 12 volt dc for vehicle battery or a hand-cranked generator; add
receptacles so it could be attached to the "burst" device; an insulated wire for the doublet so it could be used in thick foliage without
grounding out but keep it light and strong; change the doublet reel to an enclosed spool with a handle, like some measuring tapes and level lines;
and the antenna reel should include an eyelet for attaching supporting lines. Delta Recon Teams used metallic deep sea fishing line as an
antenna and it was attached to an empty surveyorís plumb line spool. It worked great except, the antenna wire wasnít insulated. We were trying to cover all of the possible situations that you could encounter in guerrilla operations, counter-guerrilla operations and direct-action
operations. Some examples of what the SF Officers called "Direct-action Operations" are the Iran Raid and the POW raid into Son Tay, North

PRC-74 Adopted, Replaces  the RS-1/GRC-109 Which Replaced the GRC-9:

[Hughes Aircraft Corporation did a great job. From the HC-162, Hughes produced a damned good radio set, the Prick 74 [AN/PRC-74]. The 74 was almost exactly what Delta recommended ó almost. Hughes did not modify the doublet antenna system. But as far as I was concerned, the 74 was still ahead of its time.

The 74 was eventually adopted as the standard SF Teamís radio set. The 74 replaced our Angry 109, which was a hand-me-down from the CIA that had replaced the RS-1, which was another CIA hand-me-down that had replaced the Angry 87 [AN/GRC-87], which was a standard army-issue radio set. The 109 was a good clandestine radio set, it was a slightly modified version of the RS-1. The best thing about the 109 was its transmitter. It could use just about anything metal for an antenna, such as a wire coat hanger, a clothes line, a jeep or a barbed wire fence. Most radios are very sensitive to the length of the antenna and for best results, the antenna must be the exact prescribed length for the radio frequency being used ó not so with the 109 or RS-1.]

HT-1 & HC-162 Use:

[Delta also used VHF sets that were like World War II walkie-talkies except it was black and weighed about half as much and were AM not FM.  They were civilian radios made in Japan called HT-1s. You could carry the damn thing in one hand and it had a greater range than the Armyís conventional field man-portable radios at that time. It also included an earphone that made it especially dear to our guys in the field. That reduced the noise to almost nothing. Noise is the biggest danger to radio communications in combat. The biggest noise with the HT-1 was when you spoke into it. Before the earphone, it was the other way around. The most noise was the squelch and incoming voices that you could only control by turning the set off and that left you with no communications at all. In a fire fight, everybody shoots at the radioman or at a point just below the radio antenna, if thatís all they see, or at the sound emitted by radios.

A Delta radio operator rode the choppers when teams were inserted and when they were exfiltrated and relayed messages between the team and base camp. They flew two commo flights every day that teams were on the ground. The teams were scheduled to communicate by radio three times a day. The third was by the 162, usually by Morse Code. They had to make at least one out of the three scheduled contacts or we considered them to be in trouble. If they misused their team code name in a message, that meant that they were captured and forced to transmit.]

TR-20 & KWM-2A as Portable Stations:

[ The Delta Commo Section had to develop a mobile base station radio because Delta operated all over Vietnam. We had to communicate with our field teams and headquarters where ever we went.

We used a TR-20 at our FOB [Forward Operational Base] to communicate with the HT-1s on insertions, extractions, and commo flights. Our mobile base station morse code radio set had to be protected so it wouldnít be damaged during all of our moving around. Instead of the standard issue field single side band [SSB] radios, we chose the KWM-2A to communicate with our 162s in the field. Ham Radio Operators loved the KWM-2A. It wasnít made as sturdy as field radios, but it was much better otherwise.  "Buster" Keaton and the 5th Groups Signal Platoon solved our problem.

They designed a plywood box that served as a trunk for transporting the radio and it also served as a permanent radio console because the
sensitive equipment was permanently mounted on shock absorbers inside the box. It even had a small fan mounted in the back to keep it cool while it was being used. The top unlatched and raised up to help ventilate the equipment and the front unlatched and hung down horizontal on two chains and served as a desk top. The telegraph key was screwed to the desk top. It worked great.]

HT-1 Use:

[ On one night commo flight, the radioman called and called for the recon team. Finally the team answered, but he was whispering and the man in the air could not make out what he was saying for all of his Vietnamese teammates chattering in the background. The man on the ground was using the HT-1 with an earphone. The radioman in the plane radioed, "Speak up! I canít hear you for all of your troops talking." A very faint reply came back, "T-h-e-y  a-r-e  n-o-t  m-y t-r-o-o-p-s!." ]

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