A.I.23 reflector size

[GreenKnight121]

For those who know... what was the diameter of the radar reflector dish in the Lightning?

One comment on a forum says 24", but I can't find an definitive statement in any on-line reference.

[Gravelbelly]

If I still worked at Crewe Toll, I could tell you - there used to be one on a stand in one of our staircase landings (there was a Blue Parrot on our floor, IIRC).

24 inches is at the upper end of "about right", but that's a decade-old memory. The best result for "AI.23 radar" on google images is from a spanish-language website, and to my dim memory it looks more like TFR (the TSR.2 set) than AI.23. IIRC the AI.23 was shaped to fit the intake and was more conical towards the rear, not cylindrical.

As ever, I apologise for my inaccuracies...

Edited to add, "found a link". (http://www.apss.org.uk/projects/APSS_projects/radar/Ferranti%20Radar%20Collection/AI23/album/index.html)

http://www.apss.org.uk/projects/APSS_projects/radar/Ferranti%20Radar%20Collection/AI23/album/medium/0001.jpg

[Softie]

Look at the size of that wave guide!!!

[Pontius Navigator]

Softie, you do mean the horn don't you?

[Fitter2]

The waveguide at the horn is 4 wavegides in a rectangular array, to give the 'monopulse' error signal. The frequency was 10Ghz (3cm). Now AI17 (3GHz, 10 cm) - that had waveguides like drainpipes.

[rhajaramjet]

The dish was in reality two parabolic reflectors joined along the vertical edge. It was a V clever arrangement; with the four-horn feed (split two to each half of the reflector) it transmitted (at 8,500MHz - 9,000MHz) four overlapping lobes which allowed the radar (unlike contemporary conical scan radars) to use sum and difference signals to angle track from a single pulse.

[radar101]

I've just been up in the loft with a tape measure to find my dish:

dish width is ~53 cm / 21 in

dish height at the join between the 2 reflectors is ~48.5 cm / 19 in

The reason for the 2 halves is that although it was amplitude comparison monopulse in the vertical plane, it was phase comparison in the horizontal plane - the L-R feed horns thus needed to be about 3 ish wavelengths apart.

:ok:

[radar101]

Softie said: "Look at the size of that wave guide!!! "

I think you are looking at the trunking on the wall!!!!

[Red Line Entry]

Hmmm, someone who'd keep an AI23 dish in his loft AND be enthused enough to go and measure it...

Sounds like someone who spent (considerable) time teaching me and many others how to derive (from first principles of course) the radar range equation at the College of Knowledge...

Does the name Caracal mean anything to you...?

[GreenKnight121]

Thank you very much, radar101. You've been very helpful.

You as well, rhajaramjet.

[Out Of Trim]

Here is another view..

http://lh5.ggpht.com/_1BXJmcdgZEw/SQcGMUq8QnI/AAAAAAAAFbE/6gm2yfDH-lc/s800/DSC_0276.JPG

[radar101]

note that in the above photo the dish is on its side

[ian16th]

Was AI 23 the only version of AI used on the Lightning?

The reason I ask, in '64 I was working in the Akrotiri, Electronics Centre, I had the Green Satin bench. When 111 Sqdn came to chase away the Turkish AF F-100's we had an AI bench added to the Radar Bay. From my dim memories of it, it was not the same as the photo's that have been posted.

The one thing that I do remember was that there was great use of wire wraps in place of the soldered connections the rest of us worked with.

[Fitter2]

AI23 was on the F1/1A/2/T4

AI23b on the F3/F6/T5

They both looked pretty much alike unless you had to service them, and like the unit in the photos as far as I recall.

Yes, hundreds of wire wraps to connect the modules. More reliable than multi way connectors, but even with the electric wrap/unwrap tools time consuming. Strictly 'modified wire wrap' - the first turn on each end included the insulation.

[cliver029]

The only difference that I came across was in relation to "Computer white" and "Computer green" where one was the full intercept version for the UK Lightings as opposed to the Saudi Version. (So we were told):confused:

As for the wire wrap why the first turn to include the insulation? doing that would have failed the fitter course but my memory fails me as to ever seeing that at Wattisham.

BTW the old DEC PDP11 computers used that method of wrapping as well?

[Fitter2]

As I recall (and my AI23b course at Cosford was in 1965, so it's going back a bit) 23b had a number of extra features, plus data link which was never inplemented at the ground end so not used in practice.

The modified wire wrap prevented a weak point at the first few corners where the post deformed the wire. The 6 (?) turns of uninsulated wire gave 24 airtight contact points in theory. There was a long and boring Ferranti document relating to acceptable techniques.

And yes, 1970's vintage PDP8 @ PDP11 backplanes were wirewrap.

[Gravelbelly]

! 11-PDP a ni deppart m'I ! pleH

(Sorry - little-endian in-joke)

[alisoncc]

Herewith one genuine DEC issue wire wrap tool PDP-11 backplane's for the use of.

http://alisoncc.com/nwimages/wirewrap.jpg

[safetypee]

IIRC, AI 23b added functions for the Red Top missile (beam and head-on firing) and there were some enhanced ECM facilities. These were in ‘computer red’; those features which were not applicable to Saudi Aircraft resulted in different ‘colour’ computers.
I am not sure if the Saudis bought the air-to-air unguided rocket-pack option (AI 23b function ? ), although they may have used them air-to-ground (not an AI function ? ); there may have been other changes due to the bombs fit etc.

For the era, AI 23 was a remarkably capable system with some very advanced features. The radar and the missiles had good capability in the then ECM environment, and overall, they had a very good ‘kill’ probability, better than comparable systems at the time and initially better than the UK Phantom fit, although the latter had a better radar (and a Nav).

[ian16th]

Thanks for the answers about the AI23. It must not look right in my memory.

As for wire wraps in computers, I can't speak for the PDP kit but IBM 1400's, S/360, 1800 DACS and 1130's all used wire wraps. Lots and lots of 'em. :uhoh:

[Jetex_Jim]

Wire wrap was devised by Bell Labs in the 1940's to address some of the several disadvantages of soldering.
First and foremost, soldering represented a reliability problem. Solder joints require a certain set of skills to effectively complete, and yet the joints themselves can easily fail if the soldering process isn’t just right – and it is difficult to measure the acceptability of a solder joint and quite messy to attempt rework of a defective one. Mechanically it is brittle, weakens with age and varies widely in strength from connection to connection. Also, soldering is prone to ‘solder splash,’ or the exfoliation of small balls of molten solder from the area of the solder joint. This can cause shorts and burn damage in adjacent electrical and electronic gear. And if the soldering iron is not properly grounded, there is a risk of electrical discharge to the costly network elements in the facility.

The other big 'cold jointing' technology, crimping was devised for the same reason.

It seems that the Apollo Guidance Computer was a wire wrap job too.

[164798]

note that in the above photo the dish is on its side

This is a picture of an AI23 not AI23B
The roll axis rotated 90 deg

[Headstone]

And as far as I know Lavenham church tower never suffered any ill effect from being used as an AI23B test target to lock onto from the radar bay window. Their fault for building the church directly opposite the large window! I think it was 7 point something miles but it was many, many years ago that I last did it.

[radar101]

We had an AI23b pointing out of a perspex window in Trenchard Hall RAFC in the 1980s. Used to be able to track cars up the road from Cranwell Village!!

[Uptime]

From Binbrook's Radar Bay, looking through the large window across the fields, Belmont TV Mast was the reference target

[tucumseh]

We had an AI23b pointing out of a perspex window in Trenchard Hall RAFC in the 1980s. Used to be able to track cars up the road from Cranwell Village!!

Similar to how Ferranti demonstrated their radars at South Gyle. A lollipop man was told to march up and down the main car park.

[pmills575]

When I was at Wattishambles we had a group visit that included the vicar of Lavenham who was most miffed that we "radiated" his church tower. As I recall we expected at least -1v on the agc meter to consider the lock good enough to send out the radar!

[ImageGear]

Ohh Dear - pull up a sandbag.

Almost every Sperry-Univac Mainframe used wire wrapped pins from the 50's until the 90's. 1004, 90/25, 90/30, 90/40, 1103, 1120, 1140, 1160, 1170, 1180, 11/90, 2200/600, 2200/900, etc. For the cousins, the 1004 also went to sea in rather large boats, Ohh wire wraps and sea air, what a combination. :eek:

I also remember (5?) a limit on how many times the same wire could be "unwrapped" and "rewrapped" before it was too brittle to bend effectively.

Each corner of the square wrapped pin also represented a single contact point and eventually the pin also became rounded and useless. Some back panel pins were completely inaccessible and necessitated some innovative techniques to rewire the open (or shorting) connection.

I always thought I was rather sad...:{

Imagegear

[H Peacock]

In the mid-80s whilst on MASUAS my QFI (Uncle Rod) arranged for me to visit a buddy of his who flew at Binbrook. I spent half a day being shown around the radar bay and recall a radar on its test stand radiating through the big window.

On one of the benches was a drill that spun a piece of wood (about 2" x 3/4" x 18") along its axis. As the wood turned they wrapped a length of uninsulated wire round it. After this they would cut through the wire along the length of the wood on opposite sides to produce hundreds of U-shaped pieces of wire. These were then used to wrap around the multiple pins in the radar boards to link them together.

I'm sure they told me that they used to have to buy these links from Ferranti before they found the much cheaper in-house solution!

[wub]

Here's one in situ

http://i66.photobucket.com/albums/h269/wub_01/wub_01059/AI23_zpsthfdadao.jpg

[tucumseh]

On one of the benches was a drill that spun a piece of wood (about 2" x 3/4" x 18") along its axis. As the wood turned they wrapped a length of uninsulated wire round it. After this they would cut through the wire along the length of the wood on opposite sides to produce hundreds of U-shaped pieces of wire. These were then used to wrap around the multiple pins in the radar boards to link them together.

This sounds right, only we had a locally manufactured metal assembly which you hand-wound, making about 50 links at a time. You had the two-piece block in a vice and hit the centre section with a hammer and it sheared the wire into links. You spent a couple of hours each week making a crate of links. Boring! The first thing you learned on Blue Orchid Doppler was there was one link that, if broken while the Transmitter was on, blew hundreds of transistors. Given they were all encapsulated, that effectively scrapped the LRU as nobody fancied digging them out with a PACE unit.

[Fitter2]

I can't remember now how many functions the hand controller had, 50 years ago I could operate them all by touch while peering at the B Scope. Anybody got a picture?

And 164798 -
This is a picture of an AI23 not AI23B. The roll axis rotated 90 deg
The dish orientation (2 half dishes side by side) was the same on AI23 and AI23B. The RF side didn't change, although the electronics behid wer somwhat different.

I do remember morning one of the AI23 Course - 'Before tomorrow go out and buy a set of coloured pencils to colour in all the relays by function set, and a bunch of hole reinforcements for the ring-binder holes'.

[wub]

Best I can do at the moment, I may have a better one but would need to scan it tomorrow

http://i66.photobucket.com/albums/h269/wub_01/wub_01060/AI_zps9xa14iph.jpg

[ORAC]

I can't remember now how many functions the hand controller had, 50 years ago I could operate them all by touch while peering at the B Scope. I knew one pilot who acquired a hand controller, bored out the centre to fit a thread, and fitted it as a gear stick handle - wired to turn on and dip lights, indicators, horn etc.

The advantages of a left hand stick in a UK car.

[Lima Juliet]

Here is a picture of AI24:

http://kingfisher.scene7.com/is/image/Kingfisher/5018719100046_01c

Oops! Sorry, that's pre-production version. Here is a picture of AI24:

http://www.projectoceanvision.com/vox/images/chapter10/foxhunter_ai24a.jpg

Anyone know if Typhoon's Captor is AI25?

LJ

[ORAC]

FMICW - otherwise known as F*** Me, It Can't Work...

[Rhino power]

Anyone know if Typhoon's Captor is AI25?

LJ

Originally called ECR90 during development and now simply CAPTOR-D (or M) for the MSA version, CAPTOR-E will be the AESA version...

-RP

[57mm]

Leon, you naughty boy. The F2/F3 had the world's finest weather radar; not much use for anything else, mind you....not mention a TD circle smaller than the target....

[grajay]

I believe you replied to my pm about this picture, but I cannot access the pm. Unfortunately there appears to be a problem with my inbox (reported as full with only one message there!). I didn't want you to think I was ignoring you.

[Minnie Burner]

I don't recall AI23 having S band wotsits.
This is 23B/C:

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/2000x1136/img_20220621_182216332_2_36fad6256fce7d45aa2d981ac6e60439866 02df4.jpg

[NutLoose]

Cough cough :O

https://live.staticflickr.com/2589/32831911162_425477de14_h.jpg

https://live.staticflickr.com/2220/32133185464_2915f1e0d7_h.jpg

[Gordon Brown]

Another one for AH&N?

[India Four Two]

grajay,

You cannot send PMs or post pictures until you have at least 10(?) posts.

[164798]

Looks like an AI 23 not the AI 23b
Many differences

[safetypee]

'S' band was part of 23b. Lightings Mk 3 - 6.
Only used it once; gave a rough indication of which part of East to look at.