EE Lightning and other Cold War era GCI data links

[yahya]

Dear Colleagues, I decided to join this forum because of the very interesting subjects, detailed information and quality of discussion. Can the experts explain how the Cold War EE Lightning's GCI data link worked and whether it was based on an AM radio channel data transmission via the on-board PTR-175 VHF/UHF transceiver, which had to be preset to the DL or DL/T mode? What kind of data was transmitted from the aircraft in the DL/T mode? How GCI commands were shown to the pilot in the Lightning's office? I assume a dedicated system to decode and process the signals aired from a GCI station was needed (like the ARI 18168/2). Was this GCI data link also available on export Lightnings? What was the nomenclature on the GCI ground processor and transmitter that interoperated with the EE Lightnings? Looking forward to your inputs. Best wishes.

 

[Grey Havoc]

Here's a post from a couple of years back with a little bit of info:

Ferranti, Elliotts and BAC developed an automatic interception system for the Lightning with a datalink which was fully engineered and tested on a P.1B. £1.4mil was spent on development but it never entered service, although the datalink was used until 1975 with ground controllers. I haven't got the exact dates at my fingertips but it most have been circa 1960-63.

https://www.pprune.org/military-aviation/205755-anyone-remember-lightning-datalink.html

That system was intended to be a major part of Tinsmith/SLEWC (Standby Local Early Warning & Control). Unfortunately there were problems with the software in the ground based computers. By the way £1.4 million was the cost of the datalink development, but the overall cost of the automated interception system project was reportedly £30 million. As Hood has mentioned, the datalink was used in a manual reversion mode until 1975, when it was supposed to be replaced by a new datalink as part of the Linesman System, Tinsmith having already been phased out around 1974. Alas, Linesman (also known as Linesman/Mediator) was a flop at best.

Interestingly, certain physical remnants of the datalink on the Lightnings were then used from then onwards by air & ground crew for the time honoured tradition of transporting life's little luxuries.

 

[yahya]

Thank you very much for the link!

I think this entry clears the issue of a radio set being used in the line (the PTR-175 or ARC-52):
https://www.pprune.org/military-aviation/205755-anyone-remember-lightning-datalink.html#post2315735

Anyway, I found another site describing how EE Lightnings were guided from the ground: http://www.raffca.uk/cms/lightningcontrol.html. This is somehow bizarre, since AM voice, if prevailed, could easily be picked up by eavesdroppers enabling them to understand how the air defence system worked, including its weaknesses, and the place of Lightnings in it.

Do other Colleagues have any factual information on the use of the above mentioned data link with EE Lightnings? Such systems seem to be common in various Cold War air forces to mention the US Link 4 or the Soviet Lazur/Vozdukh, but there were obviously issues with reliability. Do you have information on data protocols used in such links to determine the frequency and duration of such transmissions?