During the Vietnam conflict, there were no individual personal cellular or landline telephones available for soldiers or sailors to use for calling family members back home. To address this, United States MARS (Military Affiliate Radio Service) stations from all branches of the service, Army, Navy, Marines and Air Force, were deployed throughout Vietnam. The MARS system offered soldiers and sailors a way to personally communicate with loved ones back home via the use of a “phone-patch” telephone connection over short-wave radio. MARS stations would allow each soldier a free 5-minute personal radio telephone call home to the United States.

The Navy-Marine Corps MARS program was established officially on 17 August 1962, and began operations on 1 January 1963. This follows the Cuban Missile Crisis and President Kennedy’s concern for viable and extended communications capabilities. Each military service had it own MARS program, networks, frequencies, operators and stations.  A ham could apply for MARS membership and help service members call home.

One of the operators explains the process in making a patch.  First the band would have to be open to patch quality conditions.  Then a MARS operator would call the MARS station in Vietnam for a “Listing” of service members who wanted to make a call, to whom and what phone number.  The only cost was a collect call charge the family had to accept from the ham’s location. The HAM operator in the states would then get a telephone company operator on their home phone line and have the collect call placed.  Once the charge was accepted and the family member was on the line, the operator would instruct the family member that only one person could talk at a time and they had to say “over” when they were finished talking and not start talking until after the service member said “over.”  Then the operator would call Vietnam for the service member to come on line.  The call then proceeded.

When using this system, soldiers were required to follow a certain protocol. Since this was a non-secure band, we were not to mention anything about where we were or what we were doing in Vietnam. The time limit was also strictly enforced – the crew member would hold up his hands and count down from 10 before terminating the call.

The most difficult part of the conversation was in remembering to say “over” when completing your comment, this was required for the ham radio operators listening in to switch back and forth. I remember speaking with my mother once when she forgot to say “over” after her comment and there was a longer than usual silent pause. I hollered into the handset several times for her to say “over” but she couldn’t hear me until the circuit was switched. Finally, after what seemed to be almost a full minute of silence, I heard her gulp and quickly respond, “oh, over,” which then allowed the switch to take place so I could talk again.  In just about all cases, MARS was the only way soldiers could call home from Vietnam. In other words, “MARS was the soldiers’ Telephone Company.”

When wanting to place a call, there was a sign-up list for your name, the name of the party you’re trying to reach and that phone number.  For us grunts, sometime. we weren’t able to use the system because of an exceptionally long waiting list or the MARS group was unable to get a decent connection. Both required time, a luxury that grunts on stand down did not have. I should mention that in any location where field hospitals were present, a patient wanting to place a call always got to skip to the front of the line.

The process was a science! Operators on both ends had to know:

  • when the peak of the sunspot cycle would ionize the ‘E’ layer of the ionosphere
  • when to point an antenna at exactly the right spot a hundred miles out in space
  • how to reflect a high frequency radio signal off the ionized layer, over the curve of the earth, and into a similar station in the United States
  • how to hook it all up to a telephone line for the call to take place.

Sometimes, when the signals became too weak to be ‘phone patch quality’, they sent and received written messages for the troops in the form of MARSGRAMS by ‘CW’, or Morse Code, that could blast through the interference.

Photo courtesy of Gardina-mars7-454

A network of more than 80 Army, Air Force and Navy/Marine MARS stations in Vietnam transmitted more than 2.5 million phone patches and handled more than 1 million MARSgram messages to several hundred stateside MARS stations, some in the homes of volunteer ham radio operators and the others on military bases.

Station Location(s) Sponsoring Units Years
AB8AB Qui Nhon HHD, QNH Sub-Area Command 66-72
AB8AC Cam Rahn Bay C Co 41st signal 67-68
AB8AD Di An 121st Signal Battalion, 1st Infantry Division 66-70
Kontum Task Force #2, ADV 70-72
AB8AE An Khe 509th Signal Battalion 66-67
An Khe 41st Signal Battalion, 1st Air Cavalry Division 67-70
DaNang 142nd Trans 71-73
AB8AF Soc Trang 52nd Signal Battalion 67-70
Long Binh USARV Headquarters 70-73
AB8AG Nha Trang 54th Signal Battalion 66-73
AB8AH Phuoc Vinh 1st Brigade, 1st Infantry Division 66-69
Bien Hoa HQ, 11th Armored Cavalry Regiment 69-70
New Port (Saigon) USS LTC Page 70-72
AB8AI Bac Lieu MACV Advisory Team 51 66-69
Ca Mau MACV Advisory Team 51 69-72
AB8AJ Cu Chi 125th Signal Battalion, 25th Infantry Division 66-71
AB8AK Phan Rang 3rd Brigade, 101st Airborne Division 67-68
Camp Eagle (Hue) HQ, 1st Brigade. 101st Airborne Div. 68-71
Song Be MACV Advisory Team 28 71-73
AB8AL Lai Khe/Thu Dau Mot MACV Advisory Team 70 66-71
AB8AM Bien Hoa 173rd Airborne Brigade 66-68
Due Pho (LZ English) 173rd Airborne Brigade 68-71
AB8AN Can Tho 13th Aviation Battalion 66-72
AB8AO Xuan Loc MACV Advisory Team 95 66-71
Cao Lanh MACV Advisory Team 84 71-72
AB8AP Hue City Special Forces Advisory Group 66-70
Camp Eagle MACV Advisory Team 3 71 -72
AB8AQ Phu Bai 8th Radio Research Field Station 66-73
AB8AR Cam Ranh Bay 1st Trans Battalion, USNS Corpus Christi 66-68
Off of Vung Tau 1st Trans Battalion, USNS Corpus Christi 68-72
AB8AS Pleiku 4th Infantry Division 66-70
AB8AT   Co A 53d Signal Bn, II Field Force Vietnam 66-68
Long Binh (north) The Plantation Units of the 25th Infantry Division 68-70
AB8AU Camp Bear Cat / Dong Tam 9th Signal Battalion, 9th Infantry Division 66-69
Bien Hoa HQ, II Field Force, USARV 69-71
AB8AU/AZ MOBILE Unit Traveled throughout AOR 9th Signal Battalion, 9th Infantry Division 68-69
AB8AV Vung Tau 369th Signal Battalion 36th Evacuation Hospital 68-71
AB8AW Nha Trang HQ, 5th Special Forces Group 66-71
AB8AX Hoi An (Hawk Hill) 196th Light Infantry Brigade 68-70
AB8AY Phan Thiet (LZ Betty) MACV Advisory Team 37 67-68
Phan Thiet (LZ Betty) 3rd Brigade, 101st Airborne Division 69-70
Tan Son Nhut (Saigon) 224th Aviation Battalion 70-73
AB8AZ Dong Tam 9th Signal Battalion, 9th Infantry Division 67-69
Phu Bai 501st Signal Battalion, 101st Airborne Division 69-71
AB8AAA Long Binh 1st Logistical Command 68-70
Saigon Headquarters, MACV 70-72
AB8AAB Bien Hoa 3rd Brigade, 1st Infantry Division 68-70
Bao Loc MAC V Advisory Group 70-71
AB8AAC Bear Cat Mountain 4th Infantry Division 68-70
Dau Tieng / Phuoc Vinh 587th Signal Company for 3rd Brigade 25th Infantry 1968
13th Signal Battalion, 1st Air Cavalry Division
AB8AAD Chu Lai 523rd Signal Battalion & 27th Evacuation Hosp & Americal Division 67-72
AB8AAE Camp Eagle (Hue) 501st Signal Company, 101st Airborne Division 68-71
AB8AAF Tuy Hoa 261st Signal Company 68-71
AB8AAG Camp Evans (north of Hue) 1st Air Cavalry Division 67-68
AB8AAH Duc Pho 11th Infantry Brigade 67-71
AB8AAI Dong Ha (near DMZ) Units of 101st Airborne Division & 5th Mech 69-71
AB8AAJ Pleiku 43rd Signal Battalion & 71st Evacuation Hospital 68-71
AB8AAK Camp Red Devil (Quang Tri) 1st Brigade, 5th Infantry Division (Mechanized) 69-71
AB8AAL Phu Loi 520th Transportation Battalion 69-72
AB8AAM Pleiku (Camp Frank Jones) 146th Signal Company 70-73
AB8AAN Dalat 5th Special Forces Advisory Team 69-72
AB8AAO Dong Ba Thin Co. D, 43rd Signal Battalion 69-72
AB8AAP Vinh Long 7th of the 1st Air Cavalry & 164th Aviation Group 68-71
AB8AAQ Camp Evans 3rd Brigade, 101st Airborne Division 69-72
AB8AAR Firebase Mace 199th Light Infantry Brigade 69-70
AB8AAS Phu Bai XXIV Corps HQ & 101st Airborne Division 69-71
AB8AAT Da Nang 37th Signal Bn Compound 69-70 China Beach 71-73 68-73
AB8AAU Phu Lam (near Saigon) Stratcom HQ, USARV/MACV 69-73
AB8AAV Song Be (Phan Rang) MACV Advisory Team 69-71
AB8AAW Cat Lai MACV Advisory Team 68-71
AB8USA Long Binh Headquarters, USARV 65-72
Tan Son Nhut (Saigon) 69th Signal Battalion, USARV 72-73
AB8SG Saigon U.S. Embassy 73-75

The last MARS facility to go off the air was probably AB8SG located in the American Embassy in Saigon during the evacuation of the Embassy in 1975. Just about every Army unit in the field had a MARS station, including Airborne Brigades, Special Forces Advisory Groups, Infantry Divisions, Transportation Battalions, Medical Units, Aviation Battalions, and of course most Signal Corps units.

The traditional land or sea band MARS Radio Phone Patch is largely a thing of the past because land and sea based MARS stations have been dismantled in favor of Satellite Phones. However, modern military aircraft are still equipped with HF radios, and many military aircrews still use MARS Phone Patches as a backup or substitute to Satellite Communications. The USAF MARS Phone Patch Net provides 24/7 HF Radio Phone service to all branches of U.S. military aircraft worldwide.

Today, satellite phones and using Skype with a laptop makes it much easier for soldiers around the world to keep in touch with families.

I think I used the MARS system twice during my tour in Vietnam. Anybody else?

I did receive an email (11/11/21) from a former officer of one of the MARS stations with some history and a funny story which I’m including here:

I say MY station because I was the Officer-In-Charge who first established MARS station AB8AAO in Dong Ba Thin in April of 1969.  Back then, the AB8AAO call sign was assigned to D Co, 43rd Signal Battalion in Dong Ba Thin, on the east side of highway QL1 across the road from the heliport, north of the town right near the westward bend in the primarily north-south QL1.  We functioned as an independent signal company and actually reported to the 73rd Signal Battalion headquartered about 12-miles away in Cam Ranh bay.
Back then, our MARS station consisted of two AN/FRC-93 systems (essentially a civilian commercially available Collins KWM-2A high frequency transceiver, the matching 30L-1 kilowatt amplifier, a 516-2A power supply, and the 312-B5 station control module containing phone patch circuitry and an outboard variable frequency oscillator for the transceiver) all of which I obtained/signed for from 1st Signal Brigade headquarters in Long Binh and flew back to our company headquarters in Dong Ba Thin on the same helicopter with the equipment.  The army also issued us a HUGE log-periodic antenna that tuned from 7 to 30 MHz that arrived a few days later compliments of an Air Force C-130 flight to Cam Ranh Bay.  We mounted it on an 80-foot telephone pole that we “acquired” from the local engineer unit just down the road and they installed the pole for us with their truck mounted 20-ton crane in exchange for a certain number of “priority” phone patches.  We set up the station in an unused Quonset hut across the street from our company headquarters.
Funny story …
To get a full kilowatt out of each amplifier, we wired each one to a 240v main while the rest of the station and the lighting ran off of usual 120v “house current.”  Because of our proximity to the heliport, we were required to install a red light on top of the pole.  During our first week on the air, one of the operator/electricians was doing some work cleaning up the wiring and inadvertently tied the light on the pole to the 240v circuit which vaporized the bulb.  Since we needed to rotate the antenna about 30-degrees from where it had first been installed, I asked my E-7 platoon sergeant to organize a detail to replace the bulb and loosen the antenna fittings so we could rotate the antenna.  The next morning when I went out to check on the station, I found him with the members of the platoon having a meeting and they had thrown all the members names into a hat to see which two members of the platoon would get the privilege of climbing this unusually tall pole with a pole-lineman’s belt and climbing spikes.  When I arrived, my sergeant said, “Sir, even I put my name in the hat and you should too.  This is a big honor!”  I complained that officers do not climb telephone poles but considering the odds (there were 17 of us in the room), I figured what the heck, I’ll be a sport for the troops.  I lost!  Ultimately, my Hawaiian E-5 specialist and I climbed the pole. 
I completed my tour of duty and left Viet Nam at the end of June 1969 so I can’t help you with the history of AB8AAO between then and the MACV control you have listed beginning in 1971.
I would appreciate your making the correction to your listing showing AB8AAO in operation beginning in 1969 under the control of Co D, 43rd Sig Bn, not 1971 as you have listed.
Thank you,
Steven Belasco
back then, a 1st Lieutenant and now a retired Lieutenant Colonel.


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