DME Gauges history?
DME Gauges history?
Can anyone assist in advising the history of when DME and its related Gauges came into being plus, when they were started to be used regularly, particularly on civilian airliners?
Join Date: Mar 2007
Location: USofA
Posts: 1,235
Likes: 0
Received 0 Likes
on
0 Posts
I'm going to make an educated guess that it was around 1965/66. A UAL DC8 was involved in a mid air over Manhattan and part of the recomendations...I think ,was the addition of DME to the civil airlines of that time.
DME was invented in Australia in the 1950's - I knew one of the gentlemen that was in the group that did it - but I don't know too many more details than that sorry.
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
Posts: 3,832
Likes: 0
Received 0 Likes
on
0 Posts
The story according to wiki Distance measuring equipment - Wikipedia, the free encyclopedia
What principle did Rebecca work on in a Vampire? IIRC it was a guage similar to a turn and slip except the needle told you left/right and the bottom gave you the distance to go. There were still a couple of Rebecca transmitters in the early sixties.
Death Cruiser Flight Crew
Join Date: Jun 2001
Location: Vaucluse, France.
Posts: 613
Likes: 0
Received 0 Likes
on
0 Posts
Airline Pilot by Eric Leyland
A little book which was published in 1957 has the following:
"Airliners on routes to Australia, the Far East, South Africa, and South America, are fitted with radar apparatus and screens, equipment called Rebecca. On the ground is more equipment called Eureka.
Radar impulses are sent out by Rebecca, on the aircraft, and these start Eureka working. Eureka then sends back its own radar impulses, which are picked up by the 'plane, on the Rebecca screen. They are usually two letters in Morse, dots and longer dashes. Knowing the code letters of each Eureka beacon, the Radio Officer on board the airliner can identify each. On the screen there is a scale which shows the distance from the Eureka beacon. The direction of the beacon is shown by 'blips' of light which appear on the screen to the right or left of centre. If they remain in the centre, then the aircraft must be heading straight for the beacon.
The most important point about the Rebecca-Eureka system is that Eureka doesn't start to operate until a 'plane with Rebecca on board comes within range, which is usually a maximum of 120 miles. It is automatic, Eureka being 'triggered' by Rebecca. Once an aircraft is within range, Eureka must start operating."
Hmm ... didn't know it was that sophisticated.
"Airliners on routes to Australia, the Far East, South Africa, and South America, are fitted with radar apparatus and screens, equipment called Rebecca. On the ground is more equipment called Eureka.
Radar impulses are sent out by Rebecca, on the aircraft, and these start Eureka working. Eureka then sends back its own radar impulses, which are picked up by the 'plane, on the Rebecca screen. They are usually two letters in Morse, dots and longer dashes. Knowing the code letters of each Eureka beacon, the Radio Officer on board the airliner can identify each. On the screen there is a scale which shows the distance from the Eureka beacon. The direction of the beacon is shown by 'blips' of light which appear on the screen to the right or left of centre. If they remain in the centre, then the aircraft must be heading straight for the beacon.
The most important point about the Rebecca-Eureka system is that Eureka doesn't start to operate until a 'plane with Rebecca on board comes within range, which is usually a maximum of 120 miles. It is automatic, Eureka being 'triggered' by Rebecca. Once an aircraft is within range, Eureka must start operating."
Hmm ... didn't know it was that sophisticated.
Last edited by Georgeablelovehowindia; 2nd Apr 2010 at 12:32.
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
.... in November 1945 I witnessed a demonstration of an airborne distance measuring equipment (DME), built by the Combined Research Group at the U.S. Naval Research Laboratory, this time at 1000 mHz and, largely based on work that Hazeltine had been doing on the Mark V IFF, at 950-1150 mHz.
Join Date: Apr 2006
Location: On the Bay, Vic, Oz
Age: 80
Posts: 415
Likes: 0
Received 0 Likes
on
0 Posts
TACAN - Tactical Air Navigation was standard fit on our Vulcans as early as 1963. Did a course on it in '64 at RAF Yatesbury. TACAN comprised a rotating ground antenna, the transmitter of which responded to aircraft interrogations at 1030Mhz or 1090Mhz, can't remember which. The difference was the 60Mhz IF freq for the onboard receiver. The amplitude modulation, by virtue of the rotating antenna, provided a direction component whilst the delay timing gave the distance. The delay timing aspect was DME.
Not sure about the emergence of non-military versions, but RCA were shipping AVQ70's (DME) to the likes of Boeing by at least 1964/5. BOAC had retrofitted additional AVQ70 units to their fleet, making dual installations, by 1968. AVQ75, the GA version, was being shipping in significant numbers by 1968 as well.
Digging deep in the memory banks, but fairly certain that Gee II or III was a predecessor of TACAN. It had a circular CRT display that showed the time between interrogations and ground responses giving distance from the ground station. Triangulation on two ground stations would give you a position fix. This also operated in the "L" band frequency range, possibly also at 1030Mhz and 1090MHz. Gee II and Gee III were 1940's/50's DME kit.
Not sure about the emergence of non-military versions, but RCA were shipping AVQ70's (DME) to the likes of Boeing by at least 1964/5. BOAC had retrofitted additional AVQ70 units to their fleet, making dual installations, by 1968. AVQ75, the GA version, was being shipping in significant numbers by 1968 as well.
Digging deep in the memory banks, but fairly certain that Gee II or III was a predecessor of TACAN. It had a circular CRT display that showed the time between interrogations and ground responses giving distance from the ground station. Triangulation on two ground stations would give you a position fix. This also operated in the "L" band frequency range, possibly also at 1030Mhz and 1090MHz. Gee II and Gee III were 1940's/50's DME kit.
Last edited by alisoncc; 2nd Apr 2010 at 22:16.
I don't know abou a radar screen with lots of blips. The Vampire's Rebecca looked like a homing needle with distance to go. Next time I am in Duxford I shall look in one of my old Vampires and check. Eureka rings a bell as the ground equipment. There used to be a fair number at airfield boundaries. What I do know was that the homing ariels were mounted on top of the outer wings, backwards for some reason. They used to pick up ice at the slightest pretence and spend the rest of the trip flapping and viabrating away.
Join Date: Jun 2001
Location: due south
Posts: 1,332
Likes: 0
Received 0 Likes
on
0 Posts
alisoncc: I'm stretching my memory now but I do not think you have the description of Gee mk3 correct. To say that it was the 1950's DME gives a false impression of its capabilities.
It was displayed on a crt about 3inches in diameter, on this there were two horizontal timebases with blips produced by the various transmitting stations.
Under the display were knobs which moved the blips and the counter numbers in small adjacent windows.
When the blips were lined up one could read off the numbers displayed in the counter windows.
Then, armed with this information one consulted the Gee chart, which showed a mass of numbered parabolic lines.
The numbers from the counter windows were transferred to the lines on the chart, which gave an accurate position. Any reasonably experienced nav could provide a fix in under 30 seconds.
Accuracy did, of course drop away at longer ranges, but quite accurate approaches could be made anywhere over England.
If one was lucky enough to have a Gee line running along homebase runway it was a simple matter for the nav to guide the pilot down the line onto the runway.
It was displayed on a crt about 3inches in diameter, on this there were two horizontal timebases with blips produced by the various transmitting stations.
Under the display were knobs which moved the blips and the counter numbers in small adjacent windows.
When the blips were lined up one could read off the numbers displayed in the counter windows.
Then, armed with this information one consulted the Gee chart, which showed a mass of numbered parabolic lines.
The numbers from the counter windows were transferred to the lines on the chart, which gave an accurate position. Any reasonably experienced nav could provide a fix in under 30 seconds.
Accuracy did, of course drop away at longer ranges, but quite accurate approaches could be made anywhere over England.
If one was lucky enough to have a Gee line running along homebase runway it was a simple matter for the nav to guide the pilot down the line onto the runway.
Join Date: Apr 2006
Location: On the Bay, Vic, Oz
Age: 80
Posts: 415
Likes: 0
Received 0 Likes
on
0 Posts
I'm stretching my memory now but I do not think you have the description of Gee mk3 correct. To say that it was the 1950's DME gives a false impression of its capabilities.
Which is not bad for a picture drawn from memory.
I always understood that Rebecca did interrogate a ground station in a like manner to a DME interrogator. Using the signal delay of the response to give distance. And Eureka the ground system had a rotating directional antenna where the amplitude modulation of transmitted responses gave a direction component. So the Rebecca/Eureka system may have actually preceeded TACAN in providing similar functionality.
I think the important aspect of all of this is that most systems evolve, rather than being revolutionary changes.
Last edited by alisoncc; 4th Apr 2010 at 04:54.
I think that Gee evolved into Decca.. Similar lattice charts where accuracy deteriorated as one got further away from the transmitters. The information could be presented directly on special roller maps but the topography was distorted bordering on impossible at the edge of cover. A mainstay of the RAF SAR, North Sea Helicopters and the fishing fleet and also used in Viet Nam until the advent of GPS. At North Denes Heliport in the early days of gas exploration the single pilot used to radio his Decca readings back to the ops room and they would tell him where he was, which way to go, etc..
Following on from my last post.
In the early eighties we pulled S76As back from America and they went into the UK HQ hangar to be fitted out IAW the CAA Regs. When I picked them up from the docks in Antwerp, Le Harve and Southampton they had DME and another thing called Omega. I flew them to the UK and after my company engineering had finished I went down to do their UKCAA C of A.
The DME had been pulled, together with the Omega and had been replaced with Decca Tans. I could understand why Decca Tans was in, it was a company standard, but I could not understand why the DME, which was free, had been pulled. I was told that it had been taken out so that the aircraft's fit was the same as every other company S76 in the UK.
Three months later the Norwegian CAA stipulated the Decca ranges were unacceptable for range chacks in Norwegian airspace, As Norway was high on the IFR diversion list there was a frantic two weeks whilst they refitted all the DMEs thay had taken out.
In the early eighties we pulled S76As back from America and they went into the UK HQ hangar to be fitted out IAW the CAA Regs. When I picked them up from the docks in Antwerp, Le Harve and Southampton they had DME and another thing called Omega. I flew them to the UK and after my company engineering had finished I went down to do their UKCAA C of A.
The DME had been pulled, together with the Omega and had been replaced with Decca Tans. I could understand why Decca Tans was in, it was a company standard, but I could not understand why the DME, which was free, had been pulled. I was told that it had been taken out so that the aircraft's fit was the same as every other company S76 in the UK.
Three months later the Norwegian CAA stipulated the Decca ranges were unacceptable for range chacks in Norwegian airspace, As Norway was high on the IFR diversion list there was a frantic two weeks whilst they refitted all the DMEs thay had taken out.
Join Date: Jul 2000
Location: Various
Posts: 290
Likes: 0
Received 0 Likes
on
0 Posts
I'm going to have agree with forget's post in which he quoted:
If you are looking for the true origin of the concept which was eventually employed as a VHF based DME capability you need look no farther than the IFF developed in WWII.
I won't get into the willie measuring of who did what first but the fact of the matter is that the operational principle/technique predated the 1950s by quite a bit. That being said, development past IFF and TACAN (a UHF based system) into a VFH capability suitable for pairing with VOR navaids was likely as described in the preceeding posts.
.... in November 1945 I witnessed a demonstration of an airborne distance measuring equipment (DME), built by the Combined Research Group at the U.S. Naval Research Laboratory, this time at 1000 mHz and, largely based on work that Hazeltine had been doing on the Mark V IFF, at 950-1150 mHz.
I won't get into the willie measuring of who did what first but the fact of the matter is that the operational principle/technique predated the 1950s by quite a bit. That being said, development past IFF and TACAN (a UHF based system) into a VFH capability suitable for pairing with VOR navaids was likely as described in the preceeding posts.
There were a couple Rebecca systems in use when I left Cosford in 1963. Rebecca 4 was just passing out, it was fitted to the station flight Annie. This used a CRT with a centre trace line where the signals were displayed as blips left and right. Once they were even you were in line and the distance down the trace gave range. This was replaced by Rebecca 8 which was a meter with left right indication and a needle to indicate range. The needle would sweep from 0 to full range when seraching for a Eureka ground station. Once it found a station it stop sweeping and indicated range. Somewhere in this mix was a short range system called BABS (Blind Approach Beacon System?).
TACAN used a 126 channel selection from about 960Mhz to 1024Mz. The two frequencies quoted ealier as 1030Mhz and 1090Mhz were used by IFF transponders, 1030 RX and 1090 Tx.
pm575
Gatwick Aviation Museum - Charlwood
TACAN used a 126 channel selection from about 960Mhz to 1024Mz. The two frequencies quoted ealier as 1030Mhz and 1090Mhz were used by IFF transponders, 1030 RX and 1090 Tx.
pm575
Gatwick Aviation Museum - Charlwood
This was replaced by Rebecca 8 which was a meter with left right indication and a needle to indicate range
SBA info pulled as to far off thread
Last edited by Fareastdriver; 6th Apr 2010 at 09:25.
Join Date: Oct 2000
Location: Bristol
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
Gee/BABS/Rebecca
The Gee I flew with at 2ANS Thorney Is, on Vampire NF10s, was the miniaturised G Mk 3 with a 3in screen The earlier Gee was a big bit of kit. The Rebecca we carried was BABS/Rebecca with a 3in scope with a vertical range line and left and right blips on the line to give L/R info or dot/dash as it was called. The Nav had to read out the data
I don't think this was the SBA. Memory says the SBA/TBA was an mf device that gave audio dot/dsh info like a radio range
Later Rebecca in the Vampire T11 and other aircraft had a range sweeping dial that locked on when it found a ground station and a small L/R needle at the bottom
Subject always to challenge
Dick
The Gee I flew with at 2ANS Thorney Is, on Vampire NF10s, was the miniaturised G Mk 3 with a 3in screen The earlier Gee was a big bit of kit. The Rebecca we carried was BABS/Rebecca with a 3in scope with a vertical range line and left and right blips on the line to give L/R info or dot/dash as it was called. The Nav had to read out the data
I don't think this was the SBA. Memory says the SBA/TBA was an mf device that gave audio dot/dsh info like a radio range
Later Rebecca in the Vampire T11 and other aircraft had a range sweeping dial that locked on when it found a ground station and a small L/R needle at the bottom
Subject always to challenge
Dick