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Radio Intelligence on the Mexican Border, World War I: A Personal View

The Radio Intelligence Service (R.I.S.) was created during World War I by the U.S. Army Military Intelligence Branch for the sole purpose of supporting strategic intelligence through radio intercept. This was the first unit of its kind and its success helped to lay the foundation for the use of radio intercept by the U.S. military.

The R.I.S. served mainly on the U.S./Mexican border, monitoring the threat of a Mexican-German alliance. Mr. Richard Egolf was one of the young men recruited for the R.I.S. in 1918. He served in McAllen, Texas, with Radio Tractor Units 33 and 34. In 1976, Mr. EgoIf was interviewed by members of the NSA History Department about his experiences in this earliest of signals intelligence organizations.

Following are highlights of that interview:

  • Do you remember the specific targets you copied from McAllen?

    Chapultepec was the name of one of the stations that we monitored. Twenty-four hours a day because they were communicating with stations in Germany, and I presume with German submarines in the Gulf of Mexico. I know we did copy when we could. I believe we got a lot of information that was very valuable.

  • Did you have knowledge of the type of materials you would copy?

    We were told, as I recall, that the main objective was to monitor signals as to what time of day they came on the air, who was being called, and what the code was. There was an awful lot of code that came out of Chapultepec and I'm sure a lot of it was copied and passed to Washington. I understand that the material had been transmitted back to Washington and it was very valuable. One of the primary points was that we monitored these stations at the exact time they came on - like that would come on at maybe eleven o'clock at night and that transmitted for about an hour and then stopped. The next night they came on and did the same thing. Well, each night whoever was on watch at that particular time could copy as much as he could without interference from the static.

  • Was there any type of a search mission where you would just copy anything?

    Primarily we copied stations that we heard which we thought were transmitting code or possibly some information that was being used by the submarines in the Gulf or was going back to Germany. The Chapultepec station - at that time called XDA - was a very powerful station. I was told later that the intelligence department had sent investigators into Mexico and had been able to get information about this particular station.

  • Could you describe the setting up of your station at McAllen?

    Well, the transmitting equipment had already been installed in the truck so the only setting up that the personnel had to do there in McAllen was to take the spikes out (which were the center of the umbrella antenna) and raise them and put the antenna up. The tent was set up right after the equipment came up there. We had a field meter which was hung on the wall, as well as an audibility meter. When you heard a station, you took readings on its signal strength and you came up with a pattern. You would then have a big lobe which was your strongest signal and then you took a reading - that was where the station's signal was coming from. As you rotated the loop around in the opposite direction, the signal got weaker. You took this signal bearing and passed that information on to one of the other units.

  • How was the antenna moved? I was wondering how you turned it so that you got the best lobe.

    It was operated manually. You turned it by hand. You see, it had a disc with degrees marked on it and it had an arrow on it which pointed to the degrees, so that when you rotated it, you took the reading off this disc on the bottom. To improve reception there was what they called the Armstrong regenerator circuit, which was one of the big things in reception. I constructed a similar one - built it and we used it. There were two coils; one was a fixed coil and the other one fastened onto a piece of wood which you pushed in and out.

  • It was a regenerative repeater?

    That's right. I made it a regenerative repeater. It wasn't in its day a regenerative repeater, but as a result of adding this it became one.

  • Would it be possible for you to describe what it was like when you came on duty - what you did? Let's say you came on at one of the shifts. As an intercept operator, what did you do? How did you set up your equipment?

    Well, the equipment was running twenty-four hours a day. Of course, we always had supplies of extra tubes and things like that. But the equipment was never shut off unless something went wrong with it and we had to fix it. In my recollection, we never had much difficulty with it at all. It always operated well and it was checked mostly every day.

  • So when you came on duty, you literally took over a warm chair?

    We just took over from the other fellow, that's right. I remember one night I came on - one of the late shifts like 11 to 7, something like that - and sat down in a comfortable chair. I put my feet down and felt something. By the way, we always kept a revolver on the table and I put my feet down and felt this soft thing. I said to myself this feels like a snake, so I took the flashlight and pulled the gun off the table. Sure enough it was a great big rattlesnake. Well, one of those smart alecs who had been on before me had cooked up the idea of giving EgoIf a session for himself. So I blazed away at this snake with a 38; then they all came running after hearing the shots. They were having a whooping good time, you know, laughing.

  • How long did you stay in McAllen?

    I stayed until 1919.

  • Did you stay on to train the new people?

    No, I didn't stay - I said I'm out and that's it!

  • We certainly thank you for talking to us and helping us. You have done an excellent job of recalling; we want you to know that.

Produced by The Center for Cryptologic History.