Primary radar systems at British airports.
 

It's been a few years since this was discussed.
At Leeds Bradford the 1989-vintage Plessey Watchman is still turning and doing the business. I believe its had a few upgrades and tweaks over the years, some very recent. As far as I know, none of the NATS airfields are still using the Watchman but I think Newcastle and East Midlands still have their Marconi S511s. Built to last ?

Still got a Watchman at EGPH. Although there is a Terma SCANTER 4002 which has been under trial for a year and I think the eventual plan is for this to replace the Watchman.

Thankyou Glamdring. I thought the Edinburgh Watchman might have gone during the NATS era but obviously not. I haven't heard of the Terma SCANTER model before. Must investigate. I know Thales and Raytheon primary radars are a popular choice for new installations these days.

I wouldn't call the Raytheon ASR10 'popular'; it's rubbish compared with the Watchman but the problem is, the users (radar controllers) don't have any say if the airport they work at decides to buy one.

Newcastle has a Thales STAR 2000 PSR and a Terma SCANTER 4002 as a windfarm infill radar. I think that East Midlands still has the S511 - a replacement/update was mooted some time ago but I don't know if a decision has been made. They also use an Aveillant Theia 16A for windfarm mitigation.

East Mids' even have their own wind farm too.

I was born and brought up not far from EMA, and went to school in Spondon, the location of the windfarm that requires the mitigation radar.

I don't mean popular as in well-loved but rather the one everyone goes for, for some indeterminate reason. What's the problem with the ASR10, compared to the Watchman and the S511 ?

Obviously I am behind the times. Most pictures of Newcastle Airport I have seen have the S511 lurking in a corner. When did they get the Thales ?

I've seen a few pictures of the Terma Scanter now but the Aveillant is another new one on me.

Leeds Bradford is surrounded by windfarms but there's no obvious extra piece of equipment for windfarm mitigation. The Watchman was 4G-proofed some years ago and a new data processor came along in 2016. I don't know if the latter has dealt with the windfarm issue though.

'Twas in 2016...

https://www.chroniclelive.co.uk/news...-high-11481086

Thankyou Simtech.

Well it's not really a Watchman. It's a Watchman antenna but the electronics were all replaced some years ago with the Sensis SPE 3000 transmitter etc, turning it into what is called an NASR10. Glasgow and the wind farm mitigation radar at Kincardine are the same configuration.

The only other remaining S511s are at Prestwick (which is another hybrid
- basically S511 electronics with a Watchman antenna) and the MoD range at Manorbier in Wales.

So Newcastle and Inverness have the Thales. Anyone else ? The Raytheon ASR10 seems to be the other new generation machine.

Interesting to read about these hybrid Watchman and Marconi mash-ups. I know this used to go on some years ago, e.g. the Cossor ACR6 becoming an EN4000 or something like that. Probably companies like Selex and MARIS get involved. How does an operator gain approval to commission a hybrid radar ?

Did Ronaldsway ever get their Watchman replacement off the ground ?

Holes.
Whereas the Watchman has Adaptive MTI and thus 'cancels' just non-moving objects and slow moving weather returns, the ASR 10 we had at Farnborough relied not only on cancelling non-moving objects but also on designating areas of the radar where the threshold speed was adjusted to cancel out unwanted moving objects too. A prime example is the Hogs Back upon which the A31 road runs. With Watchman and its predecessors you could see road traffic on it and you got used to it; they were only tiny 'blips' anyway, but the ASR10 displays a much larger processed symbol and has this whole area cancelled by a threshold speed of supposedly 50kts rather than the 30kts around the rest of the picture; all I know is anyone flying a slow moving aircraft or doing training or aeros in this area doesn't show at all on primary radar. A similar effect occurs in several other places, plus of course the setting up PEs have to be in an area where the threshold speed is set to zero.
Unless you had worked with the AR1 and Watchman at Farnborough, you wouldn't realise there are holes, but they are definitely there.
Never seen an S511 picture so I don't know what it would be like.

I understand that all the Watchman radars at MOD sites will be replaced by Thales equipment (possibly the STAR 2000NG) as part of Project Marshall, the modernisation/update programme for military ATC.

Thales STAR-2000s at Newcastle, Inverness, Manston [since withdrawn], Belfast International, Cardiff, Oxford, Guernsey, Birmingham, plus 20 at RAF and other military units, first one now in place, others being installed up to 2021.

Isle of Man has a Leonardo (formerly Selex) ATCR-33S. Commissioned Sept 2017. Other ATCR-33s at Southend, Bristol, Belfast City, Bournemouth and Newquay. Plus an ATCR-44 at Warton.

Re chevvron's "holes", quite apart from the different MTI threshold speeds, this is an inevitable consequence of replacing raw video display radars like the Watchman with plot-extracted radars. The former will display anything deemed to be a valid plot on first scan; the plot-extracted radars have to see a plot on at least three consecutive scans before they'll display it. For things like gliders that may appear fleetingly on only one scan, this inevitably means the newer radars will be giving a lot less information on this type of target to controllers. For those providing ATSOCAS that can be a significant concern.

It will be particularly interesting to see how the RAF deals with this issue with their shiny new STAR-2000s.

Might be an idea for LBA (and anyone else who still has one) to hang on to their Watchman for a while longer, or at least until the 'holes' get filled in.

Its been a while since I've been there but since LBA is pretty much on top of a hill, are the wind farms nearby effectively below the radar's field of view?

Are you certain about that? From what I remember the Marshall budget wasn't anywhere near enough to replace all the primary radars along with all the other stuff that it had to cover.

PDR

The windfarm at Ovenden Moor is the largest and most obvious (I can see it from my home in Yeadon). I don't know its elevation but it can't be far off LBA's elevation of 682ft, if not higher.

As far as I am aware, yes. The replacement program is scheduled to run until 2021 and involves the supply of 20 PSR and 4 SSR systems.

The PSR at Prestwick is an EN4000, as NorthSouth correctly pointed out, a hybrid Watchman but it is being replaced by a Terma Scanter 4002. This has been on site for over a year but hasn't been flight trialed yet.

I noticed on eBay yesterday a couple of radar heads for sale, a Watchman and a Raytheon. Both, apparently, unused. I think I'll pass !

Is there any market for used S-band radars or do they end up in the scrapyard ? I often wonder what happened to the old ACR430 that graced Leeds Bradford for more than twenty years. The Watchman has outlived it by some margin.

Better tell Talkdownman about those radar heads; they're always searching for spare parts for Lasham Radar.
By the way, the '430 is X-band (3cm) not S-band (10cm)
From memory, the 430 head was not dissmilar to the Watchman head, the difference being the 'guts'.
The 430 was a development of the 424/ACR7 which in turn was a development of a shipboard radar; the 424 only had a 'pencil' beam whereas the 430 had a pencil beam and a 'cosecant squared' beam same as the Watchman.
The 430 operated on a pulse generated by a klystron or magnetron whereas the Watchman used a 'Travelling Wave Tube' or 'twit'.
The 430 had no MTI, the Watchman had 'Adaptive MTI'.

There was a Decca 424 at Leeds before the 430. It ended up at Brough.

Would Raytheon and Watchman spares be any good for a 424 ? It used to be Ford Anglia belts that were sought after !

From what TDM tells me, it's valves they're short of; but then none of you lot probably knows what a thermionic valve is.

I do not but I guess it's heat-related. And a valve.

My TV set used to have about 24 of them.

Oh so have they now decided that the Scanter will do the full job, without a replacement for the EN4000? I understood there was some doubt about providing the service with a radar that only has a range of 40nm

Ha ha that's a good one! NATS sign up to a contract that doesn't cover its costs? I would have thought £1.5 billion would just about cover it. But they're already way behind the contracted schedule and not getting any quicker.

Ovenden is visible on the LBA Watchman and is not mitigated.

Interesting. Perhaps windfarms aren't an issue round here. However I don't work in ATC so I don't know for certain.

Valves were what made 'steam' radios work. They were superseded by transistors in the early '60s and they have now been pushed aside by silicon chips.
Y'know those documentaries about the Bombes used to make Enigma decoding work? Did you see those funny shaped glass things like lightbulbs inside the Bombes?
They are valves.

A fascinating discussion indeed, I wonder how much 'Radar Theory' is included in modern APS/ACS courses?

@ ZOOKER
Who can forget John Townsend's erudite explanations of tangential fade & associated equations ? ;-)

...and his Sine Wave 'soft-shoe-shuffle'...

JT got a lot of radar theory across to a lot of students who wouldn't otherwise have got it! Most memorable and entertaining! I owe JT...

I think many of us do TDM. Always enjoyed his lectures, and using a primary-only fluoride radar was one of the most satisfying aspects of the job.

Is a fluoride radar a green monochrome display, as opposed to an orange one ? They once had those at Blackpool, Stansted and Birmingham (Ferranti ?), as I recall, probably fed by any number of primary radar heads.

Our Decca 424 was orange. We have succumbed to flat screens now. I understand the old 1950s kit has gone to the Plessey museum on the IOW. The fluoride had lost almost all of its persistence towards the end. We were vectoring fast-decaying pin-heads.