ASVBA?

HI I have a copy of am old airfield chart for Homsley South. Some 500ft of the end of each runway, on the centreline is "A.S.V.B.A. Hard standing". Its position suggests a beacon or approach aid. Any one know what it was?

Air to Surface Vessel (ASV) Radar was 1.5 metre radar used by Coastal Command for hunting ships and U-boats. Many stations were fitted with ASV homers which were transmitter-receivers (transponders) located on the airfield. When an ASV equipped aircraft pointed itself roughly towards the transponder it triggered the latter which returned a stream of pulses on which the pilot could accurately locate the airfield. (Range around 80 miles).

Some clever guys at Limavady took the idea a stage further and turned it into a Blind-Approach system (ASVBA, or BABS Mk.1C). They installed an aerial system as below, just off the end of the runway, near the plinth which supported the SBA system ('cos the latter was **** and didn't work!)


The centre aerial detected the radar of an approaching ASV aircraft and returned the signal via two angled aerials for 0.2 sec into one and 0.8 sec into the other. Thus the pilot received a sort of dot and dash pattern which told him which side of the runway he was on.
Coastal Command attempted to install two sets of the equipment at the end of runways which pointed out to sea. The remaining four 'ends' were serviced by a portable version of the above. It took an hour or so to set up but obviated the need for lengthy cable runs from the control tower.

A half-way house version had fixed aerial systems, but transportable electronics contained in a van. Advantage being the aerials were already accurately aligned.

Fighter Command with their Airborne Interception radar received a follow on version (AIBA, or BABS Mk.1F) which operated on the same band but used a completely different aerial array (corner aerials). Bomber Command eventually got BABS Mk.II to work with their H2S sets. The transponder was known as Lucero, and I remember the site plan for Marston Moor shows Lucero Plinths off the end on runways. The BABS systems were very superior to SBA.

Carnaby

What does SBA means... ?

olympusman wrote:

What does SBA means... ?

SBA was the means by which the Air Ministry had been assured that they could land bombers in 30-metre visibility at 100 second intervals.

It was a version of the German Blind Landing system developed by C Lorenz AG. Their sister company, Standard Telephones and Cables of London, obtained the licence to manufacture it in the UK as the Standard Beam Approach.

The first two systems were sent pre-WWII to Gatwick and Heston. They couldn't get the former to work at all, hence it was abandoned. Heston's worked for a short period but by the time other structures had been erected on and around the site it was deemed unusable. Next was Croydon - it too had severe problems with a distorted beam. With the writing on the wall the Air Ministry pressed ahead and installed it at a very large number of sites and wondered why it was deemed unacceptable by the pilots. The aircraft receiver, the R1124, had to be completely redesigned in 1942 as the 20,000 or so already manufactured were totally unstable.

With the revamped receiver it became a possibility but with the constraint '...for the average pilot the system was only usable with a horizontal visibility of 2,000 metres and cloud cover not less than 250 metres.'

Regarding the 100 sec landing time, the best they ever achieved was 6 mins per aircraft. Typically just four aircraft per hour was achievable. It was all a very expensive mistake.

For a picture see Entry #23

Graham

You can better see it at Stoney Cross as theroad & hut base is still there
wikimapia.org/#lat=50.9070381&lo ... =0&m=a&v=2


It is exactly the same layout as Holmsley South.

Richard

www.atlantikwall.co.uk

wikimapia.org/#lat=50.7833177&lo ... =0&m=a&v=2

A link to Holmsley South's

Gentlemen, many thanks for your multitude of replies. Now I know where to pose those awkward little questions in the sure and certain knowlegde that the answers will be far in excess of my expectations!!
Once again thank you!

Kit