Primary Radar Scanners

[The Great Unwashed]

As an interested onlooker, I was wondering what factors are significant when a U.K. airport selects a replacement radar head, apart from purchase price. From the airports I've seen in this country, there doesn't appear to be much choice. It seems you either have to go for a Marconi S511 or a Siemens Plessey
Watchman, although I believe Staverton has something called a MARIS.

Virtually all the NATS airports have the Watchman, except for Cardiff which has a Marconi ! Do any controllers have any preference, or is there not much between the systems on offer.

Thanks in anticipation.

:ok:

[HEATHROW DIRECTOR]

<<Do any controllers have any preference, or is there not much between the systems on offer.>>

Controllers' preferences do not enter the equation at all if they are employed by a large ATS provider. At smaller units they may well have some say in the matter. The "powers that be" select a particular piece of equipment and the controllers have to get on with it. I personally preferred the old-fashioned "raw" radar to the new-fangled digital scan-converted stuff... but new controllers only know the current equipment and are, presumably, happy.

Actually, when all is said and done there probably isn't a great deal of difference between particular pieces of gear provided they meet the requirements for the task in hand. All the controller sees is a radar display and he will be (reasonably) happy if it shows what he wants to see. However, as I suggested earlier, most don't get a lot of choice.

[SATCO Biggin]

No truth in the rumour that all NATS units use the same type of radar so that they can all copy each others Safety Cases then.:O

[Standard Noise]

There are no other factors. Airports are run by beancounters, not people with any sense.
Still, I've worked on 511 at my last three units and it's fine. Mind you, it's not the buying of the radar that's the problem, it's whether the beancounters shell out for a proper maintenance and spares package, which in my experience, they don't.

[BEXIL160]

Used both the S511 and the Watchman, both quatum leaps over the AR1 (or AR1.5!).

Both provide extremely good coverage with little loss of signal (fibre Optic cabling) The real clincher is the type of displays they can be used with. There are a lot of options, mostly expensive and beancounters will usually ensure that you end up with the "base" model.

The Watchman "Crown" consoles that the kit originally came with were pretty basic, but again quite an improvement over that which they replaced.

Nowadays Colour displays are much more popular, and user friendly (Just don't get the Royal College of Art to do the colours, they'll completely muck it up.. see Swanwick)

Rgds BEX

[The Great Unwashed]

Many thanks to those of you who have taken the trouble to reply.
It's a shame that it appears that beancounters' and management preferences take precedence over those of the controllers. Maybe there simply isn't that much difference at the end of the day, as long as the display is good quality.

Can't speak for the AR-1 but I once witnessed the picture of an old Plessey 430 in action. Could hardly see a thing ! Mind that was about seventeen years ago when this particular airport was still using PPI displays and had no SSR. Thankfully things have moved on. It's also interesting to note that although virtually all airports have SSR capability these days not all have their own SSR hog trough, e.g. the NATS airports, Bournemouth and Newcastle are sorted OK. Are there any obvious advantages to owning your own SSR gear as opposed to buying the data in from another site ??

[SoftTop]

From memory, the criteria used for a radar's ability to detect a target is based upon a 1 sq meter cross-section at max operating range, which for airport radars tends to have a cut off at about 60nm. Although, 80nm seems to ring a bell for some reason.

I also seem to recall the the LL Watchman was replaced by a Raytheon sensor a couple of years ago.

There needs to be a bit of care taken when talking about "radar". The detection performance is almost entirely down to the equipment out at the radar head. The processing and display side of things offers a much wider set of options in terms of equipment and display technology, and it is the bit (usually) in the equipment room adjacent to the controllers.

I can't think of any NATS units that still use a genuinely analogue picture, I suspect that they're all plot extracted these days.

ST

[BEXIL160]

Yes there ARE advanatges to having your own SSR.

Relying on a "third party" supplier means you are completely in their hands when they decide to withdraw the SSR for maintenance, upgrade etc.

Having your own means you can decide the best times for maintenance, or upgrade.

Southampton (Solent Radar) have been "victims" of this. Their only SSR feed is from NATS Pease Pottage site near Gatwick. this has been withrawn for lengthy periods for maint, and currently is undergoing a major rebuild. So no SSR for Solent.

Meanwhile, down the road in sunny Bournemouth, they have their own SSR antenna and rarely have to work without it. They can withdraw it at a time convienent to themselves for maint.

Of course COST is the big thing here (as ever), so it may well be cheaper to "buy in" SSR data, however unreliable. Certainly the afore mentioned beancounters will see it this way.

Me? I'd go for my own source for the reasons above, or perhaps two feeds from a third party (Farnborough had this years ago).

Rgds BEX

[Bear 555]

Bex,

Your comments are well directed. As one who has worked (maintained) AR-1, AR-15, ACR-430, Watchman and many others over the past 25 years I completely agree with your point about processing and display equipment. These are the keys to provinding the best (in my opinion) service to the controllers.

The Watchmans Signal Processing makes for a very clean and tidy picture compared to days of old. With a new display (PC based) system the final output can be very impressive. I have recently put a system in overseas which has Watchman feeding through to Alpha workstations driving Barco 29" CRT displays. Even I was impressed! Just a shame the budget would not extend to the new 29" ISIS LCD panels.

Contracting in the service seems to be gaining popularity with the bean-counters. It can all be tied up in contracts and put to bed - in theory. Sounds like the easy management option.

Subject to an appropriate budget (!) an airfield will NEVER be able to beat having its own primary, secondary and relevant maintenance staff.

What prices operational safety.

cheers all,

Bear 555

[BEXIL160]

From my dim and very distant past,

Hypothetical radar target = 10 Square metres (Icao 15 Square metres).

Range Max = the 4th Root of Pt G theta Ar, over 16 pi Pr min (in metres)

Whats it mean? No idea now, but it's the max range Radar equation as taught (drilled into me) by the John Townsend school of Radar theory... I think....:confused:

Other "gems" dimly remembered from that era are "Tangential Fade" , often referred to as Tangenital fade (a factor of age methinks ;) ) and "Blind Speed"

How things have changed.....

rgds BEX

[Simtech]

Pmin = minimum receiver power - the weakest signal the receiver can detect.

Ae = effective aperture = the area of the antenna that collects the received signal.

Theta = radar cross-sectional area of the target.

Pt = peak transmitter power.

I can't dig out my radar notes at the moment but I think the equation I was taught at college (marine radar) also included the radar wavelength, pulse repetition frequency, pulse width and antenna rotation speed.

My brain hurts now!
:oh:

[shack]

HD you wrote
"I personally preferred the old-fashioned "raw" radar"--

Does that mean you used to look forwards to Wednesdays when the ACR6 was off and we used to manage with the Marconi 264??

[HEATHROW DIRECTOR]

<<Does that mean you used to look forwards to Wednesdays when the ACR6 was off and we used to manage with the Marconi 264??>>

You mean when Tiny got his screwdriver going on the ACR6..... and those half-crown size blips on the 264? Good old days..

[shack]

How could I have done so, but I had forgotten Tiny, as you say happy days.

[Loki]

Ah, the 264!


A man`s radar that was.

[HEATHROW DIRECTOR]

I heard a story maybe 40 years ago that Marconi went to (Windy) Wellington, NZ to instal a 264. They decided the best place was on top of a very high hill but locals said the wind would be too strong and it wouldn't last. The Marconi blokes were unimpressed and said their gear could withstand anything. First strong wind and the antenna blew off the hill!

Anyone confirm that or is it "one of those stories"?

[The Great Unwashed]

Thankyou again everyone. Is there anyone out there still using the old PPI displays ? Last one I saw was at Blackpool in '97. Green graphics rather than the usual orange; lovely bright and clear picture though. Shame the radar head wasn't turning !

[Chilli Monster]

HD

Don't know about Wellington, but the military had a scanner not dissimilar to a 264's atop Saxa Vord Hill in the Shetlands. One night the picture disappeared and on investigation the head was sat quite happily in Burrafirth at the bottom of the hill. Guiness book of records had an entry saying although it wasn't measured it's thought that the gust was in excess of 150Kts! (the pictorial proof was on the wall in the Station Commanders Office).

Of course, there's still a 264 in use in the UK, and the displays are Watchman consoles as opposed to rasters - still does the job alright though (mind you - SRA's are interesting ;) )

[matspart3]

No longer in use, but I've got 3 Kelvin Hughes PPI's you can buy and a KH Nucleus raster display...as seen on the bridges of super tankers! They're all gathering dust in our maintenance shed. The last of our 430 scanners was last seen heading south on the M5 strapped to the back of a flat bed transit....

The MARIS 900 (which used to be an ACR430 in a former life) runs on 20" Belnea monitors as found in PC World!!

[HEATHROW DIRECTOR]

<<mind you - SRA's are interesting >>

I'll bet! I remember doing SRAs on the 264 at Heathrow. The target was as wide as the two runways centrelines! Answer was to wind the gain down until you just had a pinprick blip (about the size of a sixpence)!

[BEXIL160]

All this talk of SRAs on less than perfect kit reminds me of the 424.

Not bad at all for half milers, when it wasn't raining, but that isn't my abiding memory.

The Tels engineers wouldn't go near the thing without being dressed in protective goggles, big rubber guantlets, a leather apron and wellies. They used to look like a lab assistant from a Frankenstein movie..... mind you, there WAS a big EHT ON/OFF switch on the console that also looked like it came from Hammer Horror:uhoh:

What always puzzled me was the fact that I had to sit in front of the two tubes dressed in shirtsleeves and a tie (yep, I really DID wear one then;) ).

Why all the protective gear chaps? Or was it just to make you and your art more mysterious?:confused:

Rgds BEX

[matspart3]

Does anybody still do half-milers?

[HEATHROW DIRECTOR]

Bex... Tels is a black art! I recall one bloke at Heathrow put his arm inside one of the old ASMI displays and touched an EHT contact whilst his elbow brushed against the cabinet. His arm was split open from the elbow to his wrist.... made his eyes water a bit.

[The Great Unwashed]

I'm really chuffed I started this one. ATC and associated equipment is a particular hobby horse of mine and it's good to see there's a lot of interest on this forum.

We used to have a Plessey 430 at my local gaff. It ran concurrently with the Watchman for about five years before being carted off to a mystery buyer. I was amazed anyone wanted it, being about twenty five years old already and second hand when we acquired it. And not all that reliable, despite the best efforts of the Tels brigade. Not sure where it went. Some said Coventry, some said Bristol Lulsgate. Doubtful but Staverton do have the Maris 900 so who knows !

I think the Watchman at our place uses Barco displays and before that FR. Don't know about the ATM and we don't have ASMI, or whatever it's called these days. I dare say it would be a useful tool.

The 430 was a ground mounted device in red and white. The Watchman sits atop a straight gantry, except for those with the SSR aerials which are on a larger structure. I don't know what the 424, AR1.5 etc look like. Pictures anyone ?

[HEATHROW DIRECTOR]

Yes, an interesting thread indeed.. When I left school I was a lowly clerk at Min of Av Tels HQ where I worked in an office dealing with the installation of telephone equipment for ATC units. There were albums of the most amazing pics of ATC equipment - radar displays, control desks, R/T and telephone panels, etc. Probably all consigned to a bin long ago unfortunately.

There should be some very interesting pics in a forthcoming book on 50 years of Heathrow ATC... upon which I shall be working this very afternoon!

[VCR]

Matspart3........1/2 milers? You do, dopey (or are you no longer current....again!);)

[BigginAgain]

The Great Unwashed (and other radar spotters;) )

You may find this site interesting:

Radar Web Site (http://www.radarpages.co.uk/)

Mostly military air defence radar stuff, but interesting stuff, especially some of the stats about power etc on the old analogue radars.

Enjoy!

BA

[moony]

Remember arriving at Southern Radar (RAF Sopley) and started traing on the 264 - then the 80 came back from servicing. What, that little blip!

[Bear 555]

The Great Unwashed and everyone else,

It is entertaining to remeber distant and not-so-distant memories!

Fancy signal processing and sexy displays are nice for sure, but real power (in mega watts) and tens of thousands of volts were much more of a challenge!!

It's certainly a safer environment for controllers and techs today.

cheers all,

Bear 555

ps - photos to follow in a few days :-)

[HEATHROW DIRECTOR]

<<It's certainly a safer environment for controllers and techs today.>>

Tell 'em that at a certain aerodrome I know... where a "modern" display blew up in the equipment room. The fire alarm didn't go off because the air con was so strong it sucked away the smoke!

[Mooncrest]

HEATHROW DIRECTOR,

I expect you'll know this one. What was the make and model of the huge circular radar displays installed in the ground floor APC room at Heathrow in the late '80s ? I haven't seen them in the flesh but pictures only and they struck me as being a little old fashioned for a new facility.

Do you know if they're still there for a back up facility ?

MC

[HEATHROW DIRECTOR]

MC... I was there in the 80s, working in that room, but there weren't any unusual displays and I don't know the make/model of those we had. In the old 6th floor room we had two 12" raw-radar displays per position, one above the other. It was usually 50cm on the top and 10cm on the bottom. When we moved downstairs the tubes were bigger. In fact they were big enough so that having the extended centrelines set to the size we had them upstairs on the 10cm tubes meant that the overall coverage was still that of the 50cm display. They might have been 16"?? Far from being old-fashioned, they were the latest "thing" at the time but many of us preferred the old 6th floor stuff.

The displays at West Drayton are, I believe, even larger (20"?), but it would take someone current to confirm..

[Mooncrest]

HD,

Thanks for your prompt reply. As I say, the displays just looked a bit dated but obviously they were pretty cutting-edge for the time.
I'd rather ignorantly expected colour displays to have been installed by then. Maybe this was a bit before their time.

[The Great Unwashed]

Many thanks for all your replies folks. Got another question for you ! Anyone remember the rather large ground-sited primary radar heads used in the seventies and eighties ? There was one at Manchester, Glasgow and Jersey as well (I think) and one at Bristol as recently as 1992. I can't put a name, make or model to it but I'm sure someone else can. Is it per chance the oft-mentioned 264 or 424 ??

I seem to remember Manchester had another radar head by the taxiway on the way to the 06L threshold. Red and white circular thing on a gantry. Is it still there ?

Thanks as ever.

TGU

[HEATHROW DIRECTOR]

If the antenna was basically a rectanglemthey were probably the Marconi 264. If the antenna had a curved top section it was probably the 232. Anyone confirm please? These would be quite big antennas. The small, circular one were probably ACR6, or similar 10cm radars..

Mooncrest: I showed round a party of Icelandic controllers in the late 70s and they couldn't believe we were using one-colour radar! British technology or something.

[Simtech]

Think HD is correct - if the antenna was a large rectangular type, mounted at ground level (i.e. not on a tower) then this does indeed sound like a Marconi 264.

[Chilli Monster]

Anyone remember the rather large ground-sited primary radar heads used in the seventies and eighties ?

Remember it! We're still using it!

Marconi 264

[The Great Unwashed]

So that's what these great big radar heads are called. You could park a Beech 200 in the space they take up ! Obviously a classic. Are they as old as they look ?

[HEATHROW DIRECTOR]

<<Are they as old as they look ?>>

Much, much older!

[Tower Ranger]

In my time i`ve worked 430 , watchman, 424 and s511 and of them all I prefered the watchman. In bad weather both the 430 and 424 could keep your heart racing and take a few years off your life expectancy as you struggled to track your blip through the background.

We`ve only stopped using "Raw" radar about 18 months ago and whilst the multicoloured tv displays are vey pretty I quite liked siiting in the dark with warm orange glow of the old tubes.

Is anyone still using raw radar these days? Or for that matter is anyone shifting upwards of 2 million pax with primary only as we have to?

[HEATHROW DIRECTOR]

I don't thing anything beats a primary radar - nothing like tuning it up yourself to provide the best picture. BUT.. the youngsters nowadays are being brought up on "TV" displays so they know no different and they do the job just as well. It's all down to a) personal preference and b) old farts like me not wanting to accept new technology!

[The Great Unwashed]

I remember when my local airfield still had a Plessey 430 it was used for doing 1/2 mile SRA's on the runway without the ILS. The closer the aircraft came, the faster the head would spin. Every time this happened I expected it to break loose and fly away. I think this was an example of a radar head in 'talkdown mode'. Back in those days there was only one radar controller and one display so following traffic couldn't be sequenced until the preceding aircraft had completed it's approach (or gone around, as was often the case). Then the radar head could settle down again. I'm pretty certain this doesn't happen with the Watchman.
In fact, I don't think 1/2 mile SRA's are available with this radar. Just 1 or 2 miles these days.

Progress all but listening to those SRA's and watching that 430 head was very entertaining.

[PPRuNe Radar]

I don't thing anything beats a primary radar

Depends what for ;) Personally, I find that trying to maintain idents on 20 aircraft and using my skill and 'spot the ball' judgement to guess their level without asking is getting a bit hard these days. Thank God for Mode A & C ... even if the old farts never adapted to it :O :p

[M609]

Give me a MSSR over a PSR any day........


(But then you need some proper airspace to bin the PSR...... :ok: )

We have a acient ASR-7 PSR on our SSR/PSR rigg, but I'm glad we have MSSR coverage from a different sensor above MSA. The PSR goes u/s all the time anyway so.......


Ranger: If you run 2 mill pax on PSR only, you have my sympathies!

[Tower Ranger]

M609
Welcome to Belfast the land that SSR forgot.
One display, one dodgy video card, have a nice day y`all!!

[Eric T Cartman]

The radars at Glasgow in the 70's were Marconi 264AH's. They were gated so contacts were only seen out to 60 miles but were capable of seeing considerably further.
I believe there is a preserved example of a 264 aerial (which was originally installed in 1962) at the old ATCC at Hack Green in Cheshire.

[HEATHROW DIRECTOR]

<<Depends what for Personally, I find that trying to maintain idents on 20 aircraft and using my skill and 'spot the ball' judgement to guess their level without asking is getting a bit hard these days. Thank God for Mode A & C ... even if the old farts never adapted to it >>

Oh I agree.. I didn't say anything about not having SSR!

When SSR first came in at Heathrow at least one watch wouldn't use it - soon as they took over they switched it all off! Said it was reducing their basic skills (and they were probably right). It was fairly standard practice on all watches for trainees to suddenly have the SSR turned off.. Imagine what would happen nowadays?

[BEXIL160]

Hmmmm SSR.....

I also recall the first time I encountered this. Having worked on Primary only (AR1 / 424) for some time, SSR was installed. I plainly remember thinking How the heck am I supposed to keep track of everything with all these numbers cluttering up the tube??? :confused: :confused:

I'm serious, that's what most of us thought at the time. How time change. Anybody have the same experience?

rgds BEX

[2 sheds]

Great Unwashed

Amused to see your description of the 430 radar aerial increasing in r.p.m. As produced by Mr Plessey, it had a choice of 20 rpm or 40 rpm. Those that I have known had the 40 rpm capability removed - it was totally unnecessary and the poor old turning motor and the mechanical coils in the displays were trying to self-destruct at that rate. Although you had a higher renewal rate at 40 rpm, the number of strikes from the very underpowered pulses was reduced so you were really kidding yourself.

The 430 was Hard Work, to put it politely - or to put it not so politely, without a whole shedload of local modifications, as a pukka surveillance radar (as opposed to just SRAs) it was a heap of sh1te!

[HEATHROW DIRECTOR]

Don't they still have a 430 at Lasham? And how about that bizarre thing they used to have at Southend a hundred years ago - anyone remember that>>

[panjandrum]

HD

That was the EKCO, developed by local company, and by all accounts was quite an acquired art in following an aircraft down the approach path!

[HEATHROW DIRECTOR]

<That was the EKCO>

Ahh.. that's it. Thanks pjd.

[2 sheds]

It was the Ekco ARAA; it utilised an "A"-scope instead of a PPI and was used in conjunction with VDF !

[Talkdownman]

HD,

I remember we had an EKCO ARAA at Elstree back in about '66. It had a little green 'A-scope', bicycle handlebars and brake levers, a photographers black silk hood and a box to stand on. As you turned around in the dark you fell off the box, clung onto the handlebar, operated the 'brake', and nearly pulled the whole contraption through the damp hardboard ceiling. Imagine that at one mile from touchdown......
It may well have been Southend's throw-out? I don't think it ever got commissioned.

We still have the Decca 424 at Lasham, going strong....ish. (Bren, email me if you wanna see it in action!)

We are hoping ATSSD will allow us to upgrade to a 430.........!

[LXGB]

Hi All,
I think Cambridge still do half mile SRAs using a 424.

Any "fans" of the CR-62 PAR out there? ;) I sometimes miss it when the new RPAR starts getting twitchy!

LXGB

[BEXIL160]

CR62? Been there, done that..... drawn the curtains, so to speak:ooh: (if you ever used a CR62 you'll know what I mean:ok: )

best rgds
BEX

[eastern wiseguy]

Welcome to Belfast the land that SSR forgot.

Just to be clear he means the Harbour.....


we woz doing FOUR million ...plus yours with Primary only until a few years ago!!

Aldergrove ....a better service from nicer people!! :O :O

[Downwind.Maddl-Land]

CR-62? Get some in!

SLA 3C - Now that was a real radar in rain and snow........And setting up the tube with all the knobs under the shutters. Happy, happy days............

[matspart3]

So it's probably only Gloucester, Cambridge, Lasham & Scatsta who still do half-milers then?

[spekesoftly]

SLA 3C? Get some in!

CPN4/MPN11 - all the knobs and tits you could ever wish for, and your own 'Kodak Badge', to monitor radiation levels.:hmm:

[The Great Unwashed]

I never expected such passionate reponses when I started this thread. It's encouraging that so many folk take a real interest in the equipment they use rather than simply regarding radar as another tool of the trade.

I've seen an aerial pic of Glasgow from the late seventies and the two radar heads are quite clearly visible. But why did they need two ?

I'm quite surprised to see some airfields are still using monochrome displays, or have been until quite recently. I suppose for some locations cost is more of a factor. Plus it appears those at the sharp end don't always get consulted when the equipment is purchased. How common is it these days for an airfield to actually get a brand-new complete radar package, as opposed to ex-demo and ex-military surplus ??

TGU :ok:

[spekesoftly]

I've seen an aerial pic of Glasgow from the late seventies and the two radar heads are quite clearly visible. But why did they need two ?

The two Marconi 264s sited at Glasgow Airport were, I believe, originally for use by Scottish Area Control. Both also fed Glasgow Airport's Approach Radar function well into the 1980s. Two heads enabled maintenance on one, without any outage, and also provided a degree of 'redundancy'.

[The Great Unwashed]

Lucky Glasgow. I don't suppose there are many, if any, airports that can call on the services of two heads if one has to be withdrawn. On the other hand, my local airport has it's own primary radar (Watchman) but the SSR is piped in from a CAA site. The advantage is that if the primary is on the blink or out for maintenance, the controllers can still provide a service using the SSR data, which would also be the case if there was a locally sited SSR head not mounted on the primary. On the downside,
if the CAA decides to withdraw one or more of its SSR heads, suddenly, no SSR data. Swings and roundabouts.

[spekesoftly]

Lucky Glasgow

Lucky to have had two primary radar feeds, but 50cm equipment was not so good for Approach Radar work - especially SRAs to 28/10 - blips the size of old pennies! :ugh: And no SSR at PF back then.

[Bern Oulli]

Hey, good nostalgic thread!

Ah, the Decca 424. I learnt all about 1/2 mile SRAs on that. Once you learnt how to tune for maximum smoke, get the set-up markers exactly lined up on the Decca plot centre-line, and discovered the difference between background noise speckle and an aircraft return, it was very very accurate. A talkdown to touchdown in RVR less than 50 m (emergency I hasten to add) was possible with a fair degree of confidence on the part of the controller. One assumes 100% confidence on the part of the pilot but then he had little choice!

The ACR 430 on the other hand was, as has been said, a pile of manure by another name. Furry edged blip (when you could find it), furry centre-line, and a tendency for the whole display to auto-align itself at an inopportune moment.

If it is (was) ruddy great antennae you are after, then the old Type 7 and Type 14 heads at Gailes Radar were a sight to behold. Rotation speed looked like a fast walking pace at the edges.

[Talkdownman]

Hey, Bern, next time you are passing Alton International come and have a pole about on the 424 for old-time's sake. But please don't spill any paint.

[PPRuNe Radar]

my local airport has it's own primary radar (Watchman) but the SSR is piped in from a CAA site

Been a few years now since the CAA has been involved in operational service delivery. It was all handed over to that 'privatised' mob ;)

[The Great Unwashed]

I have a confession to make. I'm ignorant.

Whilst I am fascinated by all the different makes and models of radar heads, good, indifferent and lousy equipment and types of display I haven't much idea of what is meant by 50cm radar, 10cm radar and so on. Is it bandwith or wavelength or something to do with magnetrons and travelling wave tubes ??

Forgive me for jargon-dropping and thankyou for your continued responses.

TGU :ok:

[HEATHROW DIRECTOR]

50cm and 10cm are wavelengths. 50cm is usually for long range and 10cm for short-range. I ought to know why, but I don't! The most popular "big" radar now is 23cm, examples of which are installed all over the UK and used as both long-range and short range.

I can't remember the wavelength of the old ASMI at Heathrow but it was noteworthy of being just about the size of a raindrop. Hence, when it rained the ASMI was useless!

[The Great Unwashed]

Thanks HD. I thought you might know !

TGU

[None of the above]

HD..........

I think the ASMI wavelength was an astonishing 8mm, ie a frequency of 35Ghz.

N o t a

[matspart3]

Finally got round to taking these pictures of the displays referred to earlier in this thread. They were 'retired' just over three years ago (and readily available to the highest bidder!!!)

The 'video map' is a piece of acetate sheet, velcro'd to the screen, with the advisory heights written in Tippex!

(This was, of course, fully CAP670 SW01 Compliant Tippex)

http://i21.photobucket.com/albums/b274/matspart3/DSC00167.jpg

http://i21.photobucket.com/albums/b274/matspart3/DSC00168.jpg

[PPRuNe Radar]

matspart3

You need a login for those links. Can you put the pics somewhere public please ?

Cheers

[Spitoon]

my local airport has it's own primary radar (Watchman) but the SSR is piped in from a CAA site. The advantage is that if the primary is on the blink or out for maintenance, the controllers can still provide a service using the SSR data, Although this may well be the case, beware that, technically, some SSR feeds are supposed to be used for labelling only and shouldn't be used for controlling aircraft. That's the official answer of course. ;)

[fireflybob]

What a fascinating thread!

From the pilot's perspective I can remember doing many a half-miler when I was learning to fly in the Chipmunk at EMA in about 1967!

More often than not we (and ATC) would fit in a radar approach on return which would keep ATC and us in practice at doing same. I can recall several occasions when we were lost in rain clutter.

I am sure ATC might have other views on this in today's hectic traffic situation but it is a part of PPL training which is no longer practised (nothwithstanding that it is not and never has been in the syllabus) which might be a useful way of an inexperienced pilot getting back down again on a bad day.

In later years on the B737 with Orion we often used to end up doing SRAs to half mile on RW 09 before they had the ILS or anywhere else (eg Bristol) where we had to. I always found them fun to fly as there was a certain amount of team work between pilot and ATC especially in marginal conditions. Those were the days!

Also I recall doing ILSs at MAN and LHR when on the B707 with PAR monitoring! Dont think anyone knew what a beancounter was in those days!!

[Gisajob]

As part of my ATCO career I spent 3 years as a sales engineer for Cossor Electronics. This was in the days of the development of rasterscan technology.

Now we all know that on a phosphor screen the blip dies as the phosphor glow dims, leaving a trail behind the aircraft. This tail is used by the ATCO to determine the direction in which the aircraft is travelling and to predict where the aircraft is going. It is a true picture as the blip is caused by radar reflection. So an ATCO can give an accurate SRA due to the history of the true position of the blip. (Stay with me it gets interesting, I promise)

The engineers were excited with the quality of the picture and explained to me that on a raster screen the ‘blip’ is a true reflection of the aircraft’s position converted to a synthetic picture. I asked the question ‘How is the tail produced’. The answer was that it is a random decision by a computer to degrade the blip in a uniform manner’. So the tail is not an accurate position indicator, it is a computer generated random depiction of the tail.

Does this explain why it is sometimes more difficult to do an SRA on rasterscan than on phosphor screens ? Is it safe to do SRAs on rasterscan ?

Gisajob

Remember MPN 11/CPN 4 and artificial angle voltage checks (ATCOs with screwdrivers !!) Damn, showing my age.

[matspart3]

I've corrected the image links on page 5 of this thread

[henry crun]

HEATHROW DIRECTOR: going back to your post on page 2 re Wellington.

I don't think the 264 aerial at Hawkins Hill ever blew off the mounts but the wind speeds were so regularly strong that it was permanently on half speed.

They also suffered from one type of interference there that might be unique.
The winds through Cook Strait, that the aerial looked down on, would some times whip up so much spray going so fast that the mti would not cancel it !

I can also tell you that if cows stray into a 264 aerial enclosure the result is very messy. :)

[HEATHROW DIRECTOR]

Henryyyyyyyy crun wrote: "HEATHROW DIRECTOR: going back to your post on page 2 re Wellington. I don't think the 264 aerial at Hawkins Hill ever blew off the mounts"

You could be right.. The story was told to me by some "Ministry" radar engineers when I was a lowly clerk just out of school. However, having driven extensively around Wellington and over the Rimutakas I'm amazed that anything stands up down there!

[A I]

Going back to Chilli's post on page 2, I believe that the radar at Saxa Voord was a Type 80 which, if my memory serves me well was a lot bigger than a Marconi 264. It was also very slow (4rpm?) with a point 3 of a degree beamwidth. The limiting factor on the display was the spot size and not the beamwidth. I think it was a 10cm beastie and showed lots of weather.

HD. There was another iteration of the ACR6. They put AR1 electronics in it, kept the round antenna and called it the T4008 or at least I think they did.

The EKCO at Southend was around in the early 1970's so I don't think it went elsewhere. It deserves (or actually did then) to be in a museum!!

A I

[HEATHROW DIRECTOR]

Type 80 - if the antenna was bigger than a 264 it wouldn't have been a 10cm, would it? What was the back-to-back radar at the old Southern Centre at Heathrow? Wasn't that a Type 80?

T4008... I think you mean EN4008, which was rejected at Heathrow because of poor low-cover capabilities. Nothing, but nothing, beats the old ACR6 - especially when a Tels bloke called "Tiny" got going with his screwdriver and tuned it up.

[Bigears]

Ref the EKCO at Southend, heres a link you may find interesting (http://www.blueplane.co.uk/lefthander/aprilissue/page16.htm) .

I remember doing a visit to Glasgow Tower about 1979 when there were the 264's being displayed in the radar room, but SSR was in the Tels equipment room behind a dark curtain. A printout was available of the raw SSR data. Must have been part of a trial.

A link to Type 84, 85 & HF200 radars here (http://www.radarpages.co.uk/mob/linesman/linesman.htm) and Type 80 here (http://www.radarpages.co.uk/mob/mrs/type80.htm)

[055166k]

Use GOOGLE....type "RAF SOPLEY"
Nice set of pics from old Southern Radar. You had to be an operator as well as a controller, alas a lot of technical knowledge is no longer taught; the modern displays are like an arcade video game.
You wouldn't want to stand too close to certain parts of a TYPE80 because the radiation was awesome...these and similar beasts used to consume as much power as a small town. and the primary blip was tight enough to run three-abreast down a 10 mile wide airway.....with time for a cup of tea between updates.
In 2005 a controller needs different skills!

[A I]

HD

Thought I'd better check my memory Bren. Type 80 was an S band 3GHz machine which indeed makes it 10cm. Antenna size is more to do with beamwidth. If you do a Google search there are some photographs with people standing by an antenna which shows just how big it was!!


Incidentally I agree about the ACR6. It was a good bit of kit. We didn't have Tiny at EGKK but eventually all the wiring fell apart and we were given the 4008. The 50cm there was a Marconi 232 with the curved top to the antenna. Now that was good. The M264 which replaced it was not up to the mark. Think there might have been a groundplane problem and seem to remember that the AFS had to pop across the runway and discharge large volumes of water in dry spells. They probably got Dick Barmby to make them a cup of tea (or had the gate to Lowfield Heath been closed by then!?)
A I

[HEATHROW DIRECTOR]

AI - OK, very many thanks for that. I'm alright with the wavelength of bits of wire but when it comes to pipe work... that's for the really high frequency people!!

[Argus]

Ah, the mighty CPN4/MPN11 - talkdowns taught at Sleap in Red and Black trucks, chasing vampires and piston provosts around Salop with servos!

Not to mention the Cossor 787 at RNAS Brawdy - raw radar without MTI but with excellent ground returns. Singularly unhelpful when trying to keep Hunters out of Green 1, the boundaries of which were depicted in chinagraph on the display.

In comparison, the S264 at Lossie in RN times was all mod cons; MTI, SSR and a video map with GEOREF for handovers to Border and Highland Radars, the latter being located at Buchan.

I recall being regaled by the exchange Crab air trafficker of the then so called 'high tech' Type 80 at Buchan. Visited one day and was horrified at the primitive facilities 'down the hole'.

Nostalgia!