Mt. Hebo, OR - an historical and recent look

Contributed by George Pell

Mount Hebo AFS is located at N45 12.8 Lat. -123.45.4 Lon at 3154 feet MSL, and is accessable from highway 22 which is south of Hebo, Oregon by the access road which is near the Ranger Station. The road was paved by the Air Force, and is still in relatively good shape. The site has been 'restored to it's former condition' although the civilian buildings including the forest service tower are still there. The actual point designated on the Forest Service maps as Mount Hebo is actually the site of the GATR (Ground to Air Transmit and Receive) site which was north of the radar site. The firing range was also on that site. I qualified on the M1 rifle there. You can locate the GATR site by junction of the road which continues on to the North Lake camp site. The site is straight ahead to the north, the campsite is a right turn to the east. The main site was just west of the road which was along the east fence line which accessed both the ranger fire tower and the cinder block building which housed the commercial radio site and the television translator system which brought television into Tillamook before cable television.

South of the main site was the Automotive Hobby Shop, which also enclosed the Tillamook Sheriff's radio equipment. The road to that site is extremely rugged, but a couple of years ago, I managed to drive there in my car. I discovered that they had also removed the Hobby Shop building. The Sheriff's radio equipment has been relocated into it's own cinder block building.

One of the newspaper photos shows the large radar dome which was supported by a superstructure on the main tower. That photo was taken when the AN/FPS-24 radar was there. Another picture shows both the main tower and the heightfinder tower without radar dishes. That photo could likely been taken in 1968, at least that's what the site looked like when I got there. The last picture shows a much smaller radar dome on the same tower. That was after the AN/FPS-27 radar was installed. Your site indicates the -27 radar was installed in 1972 (I think that's what I saw). In fact, it was being installed in 1968 and was completed sometime after that as it was fully operational for quite some time prior to my leaving on August 10, 1971. I recall it going operational because just before it did, one of the AVCO civilian contractors was killed when he disabled the interlocks on the transmitter pulse transformer room and entered it with power on. He was killed instantly.

The pictures also show the corrugated metal sewer pipes which ran from building to building and even under the road on the main site, and the main access tunnel which ran from across the road from the security shack down to the radar towers. They were used to protect personnel from the high winds and massive amounts of snow which accumulated on the top of the mountain. I recall setting a six pack of beer on the snow outside my window -- not too unusual unless I told you my room was on the second floor.

The Portland Radio and TV weather reports would always call for the current wind speed during storms. It would generally be in excess of 90 mph -- and we would lose the anemometer a couple of times a year when the winds exceeded 150 mph. One winter, one of the NCO's parked his travel trailer against the north fence and went to work. When he got off work, the trailer was gone. He accused everyone of playing a practical joke on him, until he discovered it sitting over the side of the hill on a fire road a couple of hundred feet over the side of the hill. The wind had picked the whole thing up, lifted it over the chain link fence, and gently deposited it on the road below. He recovered it the next spring when the snow melted, and the only damage was a broken window.

One of the color photos shows a round radar dish inside a radome. That photo is of the AN/FSS-7 SLBM radar. At one time, that was a highly classified radar. The FSS-7 would sweep around just like the search radar dish does. But when it detected a possible missile target, the computer would stop the sweep, and begin quickly scanning back and forth horizontally, and at the same time rocking up and down while tracking the path of the target. One problem with the system was that the rapid deceleration of the massive antenna would sometimes shear the main spline shaft, and the dish would no longer be controllable. That system was controlled by a mini-computer which was physically about the size of a [DEC] PDP-11.

About halfway between Hebo Lake and the top was the key personnel housing area. It was located just where the snow began to stick. On really bad days, you would park at the housing area and ride the snow cat to the top. Otherwise, you would stop there and put on your chains. I carried a set of snow tires with chains already installed. When I got to the housing area, I would change tires. It was easier than putting on chains in the cold.

Commercial power was available at the site, but the only thing it powered was a single clock in the power house. The site was completely independent of the power grid, and the commercially powered clock sat next to another clock powered by the generators. The powerplant operators would compare the time on the two clocks and tweak the speed of the generators to keep them synchronized to the same time. That way, everyone would get to work on time every morning.

All of the Air Force buildings have been removed, including the housing area which was located at the snow line along the access road. There were several buildings including a two story airman's barracks, the orderly room/commanders office, an open bay barracks, a commissary, a bx (with a single lane bowling alley), a carpenters/machine shop, security police building, a chow hall, an airmans club, an officers club, a power plant with fuel tank, a MARS station, and a recreation center.

There were three radar towers, the main tower was built to support an AN/FPS-24 radar which had a huge parabolic refector which would catch the +100 mph winds and cause all kinds of grief for the radar technicians. After several attempts of trying to build an oversized domes over the dish, only to have each one blown down in the high winds before they could be completed, the Air Force finally gave up and in 1968, replaced the AN/FPS-24 with a much smaller AN/FPS-27.

The other two towers housed an AN/FPS-90 heightfinder, and an AN/FSS-7 modified as a SLBM (Sea Lauched Ballistic Missile) defense radar with a range in excess of 700 miles. This radar was capable of tracking missiles from the launch phase, through re-entry and would calculate the impact point giving about 7 or 8 minutes of warning in case of a surprise attack. I observed this radar tracking satellites as they passed overhead.

I was NCOIC of the AN/FST-2 Radar Data Processing System for a short time while the other members of my group went to school on the AN/FYQ-47 (I think that was it's designation) which was an integrated circuit design of the Radar Data Processing System. The AN/FST-2 had approximately 7100 vacuum tubes in three bays of racks, powered by two 400 cycle motor generator sets. The system would process the raw radar data, antenna position information, and IFF data, and transmit it (at 1200 baud, I think) over dedicated phone lines to the Direction Center at McChord Air Force Base, Washington, where it was processed and displayed by the AN/FSQ-7 located there.


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