Eureka, Rebecca and DME

[guym-p]

I am attempting to mimic the function of the Eureka/Rebecca (Mk.8) in a flight simulator. I have useful information on the system itself, but none on the locations and coded channels (A-H and 1-8) of the Eureka ground stations. I appreciate it's a system that was rendered obsolete long ago, but I hope that there are enough for whom it was once second nature to find this out. Was it written on charts, or in a list?

I'd be grateful for any hints, pointers or clues!

Guy.

[Fareastdriver]

There is an article in Wiki:

https://en.wikipedia.org/wiki/Rebecca/Eureka_transponding_radar

My experience was on Vampires. It was never used in anger because we did not have any procedures. The was a pair of ariels above each outer wing and they would vibrate frantically in any icing situation. The instrument was a left/right needle with a range counter. Sometimes it would wander and some numbers would come up.

[guym-p]

Thank you! It was used for civilian DME as well, before VOR/DME shared the same frequencies, so the information must have been widely available circa 1960. Like Decca charts, though, thrown away when no longer required!

[kenparry]

For civilian DME? Are you sure? I used the kit in JP, Vampire, and Hunter, through the 60s. My recollection is that, with a few exceptions, the ground beacons were only on RAF bases (maybe RN? Not sure). Coverage in the UK was good, overseas pretty minimal. When ferrying Hunters between UK and the Gulf, we had beacons available at Luqa, El Adem, Akrotiri, and by prior request Teheran (Mehrabad), then Bahrain, Sharjah, and probably Masirah - memory is a bit hazy. The Hunter 9 had an ADF as well (which was not a whole heap of use), but navigating much of that route was mostly point and hope - and hope the cloud was sufficiently broken to be able to map read. Happy days!
If you do find evidence of civil use, I would be intrigued to learn the details.

[BEagle]

The ground station was 'Eureka' and was indicated on the en-route chart by a small black circle with a white 'E'. It worked on frequencies around 220 MHz, whereas 'civil' DME is on 960-1215 MHz.

See: https://www.pprune.org/aviation-history-nostalgia/410843-dme-gauges-history-2.html

[guym-p]

Thank you. I am amazed by hair raising stories without modern (or even adequate) navigational aids. Speeds reached 500 MPH long before the instruments were up to it. Point and hope, indeed; skill, more like!

Regarding civilian use, the answer is yes, but clearly not for long. In the BOAC Comet 4 Operations Technical Manual, DME pages dated 6 May 1960, the system is introduced as "Airborne Distance Measuring Equipment Mk.8B", and goes on to say, "On the omni-range aerials, ranges up to 200 nautical miles from Eureka Mk.7 beacons may be measured when the aircraft is at a minimum height of 28,000 feet."
This early DME system was by Murphy, who also developed and manufactured Eureka/Rebecca hardware. The DME control unit is in a smaller enclosure than a Rebecca Mk.8, but would have been immediately familiar to you, or any RAF pilot joining BOAC: the knobs are the same colour, marked the same way, with the same frequency letters and numbers, the same "omni/homing" switch, and so on. The range and heading indicator and distance flown gauge are identical to those used for Rebecca — same part numbers, too.

The trouble I have finding out about this now is that the system was short lived (at least in airliners), removed only a handful of years after installation, and forgotten about. Were Eureka channels listed in the RAF En Route Supplement, perhaps?

Guy.

[spekesoftly]

Were Eureka channels listed in the RAF En Route Supplement, perhaps?


Yes they were. I've a 1983 RAF En Route Supp, and for example it shows Eureka channels listed for Cranwell and Linton-on-Ouse.

[guym-p]

The ground station was 'Eureka' and was indicated on the en-route chart by a small black circle with a white 'E'. It worked on frequencies around 220 MHz, whereas 'civil' DME is on 960-1215 MHz.
Thank you, BEagle. I found a good deal of technical information about Eureka/Rebecca at "vintageavionics.nl", and he quotes your description of using it in a Vampire.

Yes they were. I've a 1983 RAF En Route Supp, and for example it shows Eureka channels listed for Cranwell and Linton-on-Ouse.
Superb! I'll snap up a 1977 edition I've spotted on eBay. Many thanks for that.

Guy.

[AvroLincoln]

In the 1960s I was sent down from North Luffenham 3rd line base to tune a Eureka located in a tiny hut at the very tip of the Rock of Gibtaltar. A plum job, one day to tune, then 6 days on the beach awaiting the weekly flight back to the UK.