Navy-Marine Corps MARS in Vietnam

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Bien Hoa Air Base, RVN 1965 - 1973

Bien Hoa is on the Dong Nai River, near Saigon The city is on a main railroad; manufactures include rubber and timber products, tiles, and pottery.  The military airfield at Bien Hoa was the site of the initial buildup of United States air power following the Tonkin Gulf incident of 1964.  During the Viet Nam War (1959-1975) Bien Hoa was headquarters for the surrounding military region.
In October, 1966, when I arrived at Bien Hoa, MARS activity at the base was nil. The station was located on the second floor of a concrete building at one end of the base, and the equipment and antennas were in disarray. Since my hobby had always been Amateur Radio, I took an interest in getting something going, and we subsequently moved what there was of a station to the other side of the base into a Quonset building and got a couple of Eldico’s on the air. Somewhere about this time, the USAF MARS Director (can’t remember his name, but he was a Major) paid us a visit. We had several hams on base and we all met with him. I guess, seeing the interest, he offered to help us procure equipment.

One of my NCO’s (MSgt Meserve) decided to spend his spare time remodeling the inside of the building, and ended up constructing a sound-proofed operating area, a waiting area for troops making calls home, a sound-proof phone booth for the phone patches, a large work and storage area, and several operating desks. The USAF MARS Director came through with the equipment and the ultimate station configuration turned out to be:

  • A T-368 transmitter and 2 R390 receivers which we used for radio-teletype operations
  • 2-KWM2A HF transceivers and associated 30L1 amplifiers which we used for the in-country tactical networks
  • 2-KWM2A’s and 30L1 amplifiers dedicated to MARS
  • A 750 W rack mounted transmitter (can’t remember the nomenclature) which we converted to use as an amplifier for one of the MARS positions. A Collins 1,500 watt 30S1 amplifier served the other MARS position

We constructed several beam antennas for the various MARS frequencies, a full-size V-beam headed just a bit east of north, a couple of dipoles (mainly for the tactical networks), and a six element cubical quad which we put at the top of a 90’ pole.

This antenna never worked well, no matter what we did to it, until a tornado came through and broke a number of the fiberglass spreaders, at which point it became the best working (and worst looking) antenna we had. (The tornado also ripped the roofs off a number of buildings near us, which actually improved their appearance) Shortly after the tornado, at the morning staff meeting, the base commander asked me "when I was going to remove that eyesore?" I told him I’d do it immediately, however I wanted him to know that the phone patch he’d had with his wife the previous night had used it. He never mentioned the quad again, and it was still up and working when I left the base.

The most obvious benefit of the MARS program was the phone patches, and by early 1967 the efforts of the USAF MARS Director had really begun to pay off, and phone patches for troops were going strong from many of the bases in RVN. Stateside anchor stations included MARS stations at McChord Air Force Base, March, and Edwards AF Bases, and a number of stalwart hams who were members of MARS, mainly on the west coast.

The general operations scenario was for the stateside stations to come up around sunset in Vietnam (AM in the states), and spread out to several frequencies. I believe they coordinated this among themselves ahead of time, and I also believe they got quite a bit of help from the radio propagation agencies in Colorado. We knew where they’d be and when they’d be there, and we’d distribute ourselves among them. The hams would come up on the MARS frequencies that are just outside the ham bands (their antennas wouldn’t permit operation on some of the more distant frequencies).

Troops would register each day for a patch (if I remember right, it was "one patch a month"), and we’d give the listings to the CONUS stations. I believe they had the cooperation of the phone company (there was only one in those days!), and a phone operator would spend the entire session with the radio operator. They’d place the collect calls, however charges did not start until the troop actually began the conversation. Some would be busy, some a no answer, so whatever one they could complete first was connected, the rest stayed on the list.

The CONUS stations would rotate through each of the RVN stations, and the phone operators would basically have the calls "stacked up," waiting. Since they were not beginning the charges until the station actually came up on the rotation, it meant a much lower phone bill for the troops’ families, but sometimes a fairly long wait from the time the collect call was placed. Patches lasted 5 minutes. The number you could complete in a night depended on radio propagation conditions, of course, but under generally good conditions, we could complete 15 or so.

An interesting human nature effect occurred quite often. All the phone patches were on HF single sideband which is subject to various amounts of noise, and often does not sound very natural. Wives would often have a very difficult time understanding their husbands, however they could understand us, the radio operators, just fine. We finally concluded that 1) They tended to focus on the noise on the circuit rather than their husband’s voice, and 2) He didn’t sound normal. They had no idea what we sounded like in real life, so they had no problem talking to us. Nearly all of them got better with time.

One afternoon, James Garner was visiting the base, and the commander brought him by to see if we could contact his wife who was hospitalized at the time. It was the middle of the day so no CONUS stations could be heard, however we were able to contact the MARS station at Clark AB in the Philippines. They had telephone service to the states (albeit fairly pricey … not a problem for "Maverick") and they managed to get his wife on the phone from her hospital room on the east coast. They had a good conversation. Along with Raymond Burr, who dropped in via chopper on one of my 1st MOB mountain-top sites north of DaNang one day, James Garner has to be the nicest movie star I’ve ever met. Our squadron commander at the time was William Garner, and I am sorry those pictures went out with all the others of that era.

Not long after the MARS phone patch activity began to ramp up, I got a message from the USAF MARS Director asking if we thought it possible to establish a network for handling written (i.e. "record") messages via MARS in addition to phone patches. I discussed it with the other volunteer operators, and we decided it was worth a try. He shipped us a couple of Kleinschmidt teletypes to augment the two Model 15’s we had, 15 or 20 cases of paper and teletype tape, and the FSK modulators/demodulators. He also lined up AK1AIR at Elmendorf AFB in Anchorage as our primary gateway.

AI8AIR in Saigon set up a couple of in-country MARS networks and we began collecting outgoing messages from units of all services throughout the zone and relaying them to Elmendorf. Slowly, the operation evolved until we were handling several thousand messages a month, both ways. The ultimate configuration had two parts:

  1. We gathered and distributed messages locally on the in-country MARS networks. These began on voice, however one Marine operator asked me once why we didn’t try CW (Morse code). It turned out there were code-qualified operators at a number of the in-country locations, and so we began using CW. Everyone seemed to have about a 30 wpm code speed (including our new squadron commander, a Major Knox), and traffic began to move much faster. We finally evolved into cutting the messages directly onto teletype tape from the in-country network. Everyone understood that when they finished sending, they’d get an "AS" (CW-speak for "wait a moment") then a pause while we cut the confirmation line onto the message and began the next header, followed by "R K" (CWspeak for "Roger, go ahead"), and they’d continue with their next message.
  2. We ended up running a full-duplex circuit to Elmendorf most of the time (sometimes also to McChord). We’d transmit on one frequency and they’d transmit on another simultaneously. This allowed each of us to put our tapes (sometimes hundreds of feet long) on and just transmit them. If a message was garbled due to a fade, we or they would just break into our transmission, send a few "bells," and tell the other end to restart at message xxxx, and then continue with our tape.  Every now and then, we’d be able to connect with a ham who was a MARS member and had teletype equipment, and some traffic was passed that way.

At one point when the circuit with Elmendorf was poor because of aurora activity over the North American arctic, a ham in California called us and told us we were loud and clear, and that she had teletype equipment and could take our traffic. She also had possibly 50 or so messages for us. She couldn’t work duplex, so she told us to go first, and we sent all our traffic (about 1.5 hours worth). She then began transmitting hers, and after 30 or 35 messages, she disappeared. We heard later that her antenna had failed trying to operate so far out of the ham bands.

When I was reassigned to McClellan AFB in Sacramento, my wife was pregnant with our second, so she flew out of Houston to her folk’s place in Los Angeles with our daughter and I drove. Grandma/Grandpa then kept our daughter while we motored up the Central Valley to arrange for housing. We had the dog (not welcome at Grandma’s), and I had a radio in the car of course. While chatting with a fellow near Fresno, a station in Sacramento broke in and told us to just come up to their place, we could have dinner and they’d find us a hotel and kennel for the dog. During dinner, he was asking me about my "ham adventures in combat" and I mentioned the above incident with the woman’s antenna. He said, "That is my mother! She was transmitting continuously into her beam antenna so far away from its design frequency that it literally caught on fire after awhile. The traps burned up there on the tower for 15-20 minutes after her transmitter quit."

Except for the few that were based at or came through Bien Hoa, the Marines provided their own phone patch facilities. However, a goodly fraction of the record traffic we handled either came from or was destined for the Marines. They (and the Army) had arranged with FTD for the troops to be able to send flowers, and they evolved a very compact message format that selected the arrangement and provided the delivery address. Some were actual addresses, but others were just a code where FTD knew the real address. We handled hundreds of these messages for birthdays, anniversaries, etc. We never knew what the flower arrangement codes were, however we did speculate some!

The MARS operation at Bien Hoa was probably at its peak when I left in late Nov, 1967. The problem of course, is that these were short tours (1 yr), so people kept rotating out, and unlike a MARS operation in the states, there are no civilians to carry the "base load" of operations and maintenance. Without a cadre of dedicated volunteers, it was hard to maintain the pace we had established (This was a second job for all the operators). I heard from a good friend, about 2 years after I left, that the record traffic operation had declined significantly. Apparently phone patches continued more or less unabated for awhile, but with the general troop withdrawal in the 70’s, even that apparently faded quite a bit.

The MARS operation at Bien Hoa was about as much of a bright spot as any that I experienced.

Fred C. Jensen  Captain USAF 1877 Communications Squadron  AI8AB - Oct 1966 - Nov 1967

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