Yes, I used telluromenters in the 1970's when working for a coal company in ND, Wyoming, Utah and Montana. First ones were MRA Something? didnot look like either the of the two shown but do remember the MRA part.(101's)? Big heavy box and were ran them with 12 volt car batteries, which were a real treat to lug up and down hilltops. they were capable of very long range, up to 25 miles it seems. thin the longest length I measured was more in the 10 mile range. Company then got a new version, CA1000's. Still long range, but way more compact and lighter to carry, with a managable battery pack, we thought we had died and gone to heaven. 🙂
I used them back in the 70's actually the CA-1000 model of Tellurometer brand.?ÿ ?ÿI also spent a lot of time packing around and using the DM-20's.?ÿ
Was pretty amazing at the time to pop 20 miles with no line of sight.?ÿ But packing them very far along with a car battery to power them made you stay lean and mean.?ÿ I?ÿ can only imagine what health risks that we all suffered from standing behind those with the radiated microwave.?ÿ ?ÿFunny, never could have kids, doctors told me I was sterile.... hmmmm..?ÿ ?ÿIn fact, an old winter trick was that you could put your sandwich behind the fiberglass cover of the DM-20, and turn it on (which sometimes was a mistake to leave cover on then trying to take measurement) and it would warm it up.?ÿ ?ÿLittle did we know the kitchen appliances of microwave ovens would come along in a few years LOL.?ÿ Guess we were on the bleeding edge of that one.?ÿ?ÿ
YES; Had the Tellurometer MRA1 in the military in 1963 , then?ÿ MRA301 in 1968 in the military(military version of the MRA3) .
MA100 tellurometer (personal use) can't remember the year I got it(used in around 1990). CA1000 bought from a friend in 2000.
I have a set of MRA3's bought from a friend around 5 years back.
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JOHN NOLTON
I usually pick up an old survey equipment after I finish a work and collect payment from a client. The wife usually allows it if profit is ok. I put it on my shelf in the office and it kinds of reminds me of the work that paid for it. It also reminds me of how hard the survey profession was in those early days compared to what we do today because of the newer equipment.
The thought alone of the weight of the early equipment makes my back hurt.
So how do you know that you are pointing in the correct direction of the other receiver?
it’s radio, so precise alignment isn’t as sensitive as an EDM. And you can sweep the instrument. There’s an audible when find it.
I used one back in 1968-69, mainly for tying from primary pillars to set local control - typically lines of 20 to 40km. As already described, you don't need to point exactly, just swing to get the best sound signal back. The distance will always be the same, regardless of the pointing as you are measuring antenna centre to antenna centre. Any offset of a few cm. in pointing over a base direction of 40km. is irrelevant.
shortest? 2-3 meters, indoors on metrology bench.
My personal best long shot is with RangeMaster: 63,000 ft. 9 glass, VA of about 8 degrees. Elevation difference about 8,500 ft; one shot. Simultaneous recip VA for trig leveling to check GPS elevation difference. About 1989 or 1990. I couldn’t hit the target. But the target crew said “we see it just fine”. (Visible ruby laser.) they had to talk me in. Then the tiniest return signal and it started to click away.
EDM at very short these days may be good. But an HP3805 under 100 ft is bit sketchy. AGA120 shooting curb ties at 10-15 ft was not best pest practices. GPS L1 static post processed at 2 meters is always fun, looking for 1 mm, back in the day, just to see if it could do it, with $5K antennae.
Like the good Mr. Nolton I used both in the Army (67-70, 656 Engineers Germany).?ÿ The MRA 1 was retired not long after I arrived.?ÿ Being my introduction to EDM I thought they were awesome.?ÿ They were somewhat more susceptible to uncertainties in temp and pressure and just like GPS they could create some strange multipath effects when shooting low over a body of water.?ÿ Years later when the first GPS satellites went up and we were working out many of the early kinks at NGS, it dawned on they're just Tellurometers in space although moving a bit faster then we did in the Army.
If I recall correctly the units we used were like this set
source: https://images.app.goo.gl/vM3mMu1omq4Ewmg89
they were quite simple to use, we only needed a short session to demonstrate.
My longest EDMI "shot" was with a Cubic Electro-Tape DM-20 in the Spring of 1983 (also my last observation with those units).
Porcupine USGS PID MR0680 in Utah (me)
to Session Mtn ET USGS PID MR0861 in Wyoming (my little brother)
206,872 feet (39.2 miles).
We made several other shots that day, but that one was the last one, and the longest.
Pushing the envelope for those units (sorry, not pictures that day).
I still have some blank "calculation forms" for that equipment (somewhere).
Loyal
1976. Laying out a triangulation control network for the City of Helena, Montana. NGS came in with their Telurometers to set the baselines for us. Didn't get to run the instrument, but got to drive the old Willies Jeep to the top of Mount Helena with the cargo load in the back. Had to pack that beast the last 100 yards. That was plenty far enough.
Well I got hold of a pristine HP3805A last year. Picked off 10,000 ft like it was nothing. Which well beyond the 1 mi brochure range. And it checks out on the CBL better than brochure too. And, it??s no worse than shagging a T2. ?ÿ
@jbstahlFellow Surveyor friend of mine used one. He said they referred to it as the MRA C__k sucker. He had two strokes this past week and is in the hospital. When I mentioned this article he got a twinkle in his eyes.
Didn't you have to add a constant over 6500 feet and add a correction to the output of a 3805? That was the one you just aimed and pushed the button wasn't it?
Ah, you are informed. In the manual it simply state ??near or beyond 2Km it does not function correctly?.
however, there was a hand written instruction sheet in the case re: over 2Km, subtract 0.220 m. And it was written that 1999.999 is good, 2000.001 is subtract 22 cm. I didn??t test the exact boundary of the 22 cm bug.?ÿ
I did compare a 2.2Km range and subtracting 0.220 appeared to be exactly the right thing to do.
the more nagging issue is the hardwired 28 mm mirror offset. And I have an array of Wild 70 mm, and a good old AGA triple 28 mm. Nightmare.
The mirror offset is only in the manual. And no HP instruction on exceeding 2Km.
Fortunately, it??s now only for demo, and more relevant: chain calibration only. And it is a fine standard for chain cal.?ÿ
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I used one doing aerial photography control. The first time I shot over 6000 feet it gave me a reading of 200 feet or so, which I obviously knew was wrong. Called HP and they gave me the magic number to add and the correction numbers. I don't think it was in the manual. We only used HP glass. It would shoot over two miles to a triple prism.