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Telemetryin the late 1960s :-))
about the time the U.S. did a moon landing
and safe return :-)))
In 2016, I was complaining about Ampex Tape Drives when used for commercial data processing in the early 1960s.
It turns out that both J.P. Moore and Ignacio (Iggy) Menendez had:
- used Ampex tape drives (for telemetry, worked just fine)
- worked at Vandenberg AFB in California
and exchanged experiences and pictures of their time at Vandenberg AFB - "Western Test Range".
I wanted to include a reference to "Telemetry, How does it work" - but there seems no such thing. Even the current (May 2016) article in Wikipedia is useless. After stating that telemetry is getting information from here to there - it just gives a long list of uses - race cars, space vehicles, inside of aircraft or cars, ...
None of the life blood of how telemetry works, data channels, data sampling rates and why, compression yes or no and why, commutation, super-commutation, sub-commutation, ADCs, PAM, PDM, FM-FM, PCM, data synchronization, demultiplexing, system time tags, calibration and conversion to engineering units, ... - very disappointing, no understanding, just fluff.
Is our world so busy, trying to learn how to run the 500 apps on our "smart" phones, that there is no time to contemplate how anything really happens? If you can't get it into a seven second sound bite for your seventh grader - just give up ???
Some notes from Iggy Menendez
Ed, in my prior life in the USAF, I had the pleasure of working with Ampex FR600 (FR800?) and FR1400 on our ground telemetry station at Vandenberg AFB, down the coast here in CA. The telemetry station was built by Radiation Inc. in contract with Boeing.
Perhaps our use was light, or the instrumentation recorders were made to higher quality standards. I don't recall us having a single problem with these, or the large Ampex tape reels, in the years that I was there.
Glad to hear from another person that actually worked at VAFB.
My time at VAFB was much earlier, back in 1962 to 1965.
I worked on the telemetry station on the hills behind Point Sal. We had at that time our own telemetry antenna, and we would record raw PCM/FM serial data, as well as the range timing signal from WWVH.
We would decode, demux, the 700+ channels of digital data from all the Minuteman I and II transducers. When I left, we were just getting ready for the MM III.
We would make some oscillographic recordings, after conversion to analog data, on CEC machines, which used a Quartz lamp and reflected the light to sensitive paper, with tini galvanometers.
We received the data from tens of transducers, and occupied more channels to reproduce faster or transient pulses. We also recorded some of the guidance computer data, from an Autonetics D17 initially and a couple of later model airborne computers.
Our raw data tapes with the digital ( Octal) data, were reproduced and sent to be further analyzed by an IBM 7090 or 94, don't recall exactly which one.
We also had the responsibility for the testing and arming of the command destruct system We had a Microdot generator from Motorola for this testing.
We were considered part of the launch control team, and physically participated with our input during the launching of these Minuteman Missiles We had the capability of real time display of selectable channels during the launch.
For instance we would inform of "ignition" when the rockets ignited and the pressure in the engine transducer was noted. These missiles were launched from inside the underground silos.
The engines for the three stage missile were always pre fueled and the missile was ready to fly in 30 seconds, anytime.
It was kind of interesting to climb in a little cage, suspended by a steel cable that went around the missile, and winched you up, down or around the rim of the silo.
We used to call that 'damned cage' the 'blue goose'..... (the space between silo tube and missile down below, by first stage is pretty tight)
At VAFB, when descending between the silo steel tube and the missile, our cage had a tendency to hang momentarily for a second or two on the ribbets, the cage would start tipping over, then let go of the hang and drop a couple of inches, to continue on down. It was a very memorable and exiting moment, that one can never forget.
Three was about two foot clearance between the missile and the side of the silo. We had to go down, by the nozzles to connect our instrumentation cables, required to be able to get the measurements, while the missile was inside the silo.
Well, I think That Ivgit carried away talking about the good old times.
Some notes from J.P. Moore
Good to hear from you. I worked on Minuteman I, I FORCE MOD, II AND III when I was active duty USAF. Stationed at Malmstrom AFB, Montana for 10 years. Very familiar with the damned workcage! We all hated it.....took longer to install then the actual job to be done. I have been known to use a rope ladder to get to the bottom of the silo to change out a sump pump. In and out of the hole in an hour. Timeline called for something like six or seven hours. Had to be certain no QC or other visitors were coming to the site ......rope ladder was for emergency use only. I considered a sump pump change an emergency.
At VAFB, during my time there, Federal Electric Corp was prime contractor for all telemetry. I worked in TAER, (Telemetry Analog Equipment Room) on VAFB roughly 83-89. We had banks of Ampex recorders, and they always worked perfectly. At least I do not remember any problems. Just keep the heads clean and they were good to go.
We would receive telemetry from TRS (Telemetry Receiver Site or Station?) which was located several miles from VAFB atop a ridge on a nearby mountain range. TRS had the antennae and receivers and would beam it down to us for processing. TRS recorded the raw signal, I think.
We also received signals from the 80' dish at Point Pilar up near Frisco. It came to us via special leased land lines. I think there was an <20 millisecond delay in us receiving it, which we compensated for.
First thing we did in TAER was run the signals through a bank of fixed freq. receivers and demuxes and then record it on our Ampexes. We had one man who was a Tape Certifier ....he would run all previously used tapes thru his special machine that erased all data and then checked the tape for drop-outs. The allowable drop-out was a very low number ....if a tape passed the test, we could use it to record on....a tape with too many drop-outs was destroyed. I think there was also a limit to the number of times a tape could be reused. We had 1/2 inch and 1 inch tapes.
Somewhere around the house I have pictures of TAER and all its equipment. I'll look for it.
It took awhile, but I found some TAER photos made in Dec. 1987. Then I had to fire up the old XP PC to use my scanner. Surprised it still works, has been in the closet for years.
1. AMPEX RECORDERS 1 INCH & 1/2 INCH MODELS. 2. TAPE CERTIFIER. That is all this guy did! 3.BRUSH Recorders: We had a ton of these things. An ATLAS launch required at least 25 Brush Recorders! Nightmare to set up and get patched to correct signal. 4.The DSS: DSS = Data Source Selector. It was an FEC invention that used 4 receivers to run a signal thru and compare them, then select the best output. It used TRS 30', 10M, & 9M antennae, plus Pilar Point 80' antenna. This where we had to delay the TRS sigs to sync with the delay from Pilar Point land line xmission. 5. JP's Decoms. We had 5 new Acroamatic PAM/PDM Decommutators in the Ground Station and they were my babies. Four had 96 DACs, one had 48 DACs. They had the capability to store up to 12 operational setups in memory. I programmed them and operated them during launches. They worked very well with the exception of some serious DAC overheating problems. I went though a lot of expensive DACs before it was fixed. 6. The Quick Look Room, across the hall from TAER. This where the customer and his entourage would come for launches or tests. Atlas launches were the worst because there were so many data channels and the user had many onlookers so we could hardly get to a Brush if there was a problem. I was lucky, stayed over in TAER with my decoms. ;>)) 7. Receiver Station. All the receivers were on a fixed channel, so there wasn't a lot to do here unless one died. Then it was pure panic. 8. The Shuttle (STS) Room. Did you know VAFB had a genuine STS launch pad and all the associated gear? It was called the Blue Shuttle (as in air force blue). We were tasked to record only the main engine data during a launch. It was all super secret, encrypted data, a pain in the ass. After going to school several months, I was assigned to work in here. Then someone found out that VAFB is one of the foggiest bases in the world, and STS launches, having humans aboard, require 100% visual contact during launch and ascent. Program cancelled. Had to have cost in the Billions to build the launch pad, MAB, roads, everything required to launch a shuttle. They even built a new runway that could accommodate the STS, super thick concrete and I think around 15,000' long.I don't think that fog was the reason, but they could have never launched if the program continued. The fog at VAFB is very serious. 9. Another shot of Ampex tape recorders.