Radar and the Air War – Part 1 – by John Heys G3BDQ

My only qualification in writing this outline of ‘Radio Location’ activity is a Wartime five years in the RAF looking after airborne radars used by the heavy bombers, Halifaxes in the main, when with several Bomber Squadrons based in Yorkshire. Most of my service time was with 77 Squadron, which quickly re-equipped with Dakotas at the end of the War in Europe.

I did test flights in Wellingtons and Halifaxes, usually to discover those mysterious faults on the equipment when aloft, but which vanished on the ground and didn’t reveal themselves on ‘DIs’ (Daily Inspections) or on the workshop bench. By the way, the Lake District looked wonderful on a clear day from 20,000ft when seen directly or via the H2S radar screen. I digress.

Radar was a word that did not exist until the Americans came into the War. I was one of a growing army of RDF ( Radio Direction Finding ) technicians sworn to secrecy and proudly displaying the badge with its lightning bolts radiating from the red circle in the centre. Radar was an acronym devised from ‘Radio Detecting and Ranging.’
I find it amazing that the screened grid valve only came into general wireless use in 1927/28 yet a mere ten years later Britain had a great chain of CH (Chain Home) stations along the South coast and up the East coast. The Germans at that time were even more advanced. Propaganda told us that we were the inventors of Radar, but sadly the Germans were.

It is a historical fact that Mr Watson-Watt and his team made the first British successful Radar tests on February 26th 1935 when near Daventry and in a specially equipped van and they received echoes of the Daventry transmissions (on 49 metres) from an elderly Heyford bomber.  It seems almost a miracle that equipment for the coastal radar stations was designed and installed, not forgetting the huge antenna arrays, before the start of the War in 1939. I shall deal in some detail with the CH stations in Part 2.

The German Contribution

In 1930, long before Adolf Hitler and the Nazis took over Germany in 1934, Dr Rudolph Kühnold a civil servant in the German Naval Research Dept. was then, and despite the Treaty of Versailles which forbade German re-armament, working on a system that could use radio waves to detect shipping and aircraft. He had considerable success so a company GEMA was set up to further the research. In 1933 the researchers started to use some new powerful radio valves that would operate on very high frequencies. These valves were made by the Dutch firm Philips.

This led in 1934 to a practical  radar positioned on a hill  overlooking Keil harbour that located a ship seven miles distant.  After this the German authorities awarded GEMA 70,000 Marks to further their research.

By 1936 GEMA was making two types of Radar for the Reich; Seetakt and Freya. The former was a ship-borne system linked to  a warship’s guns and was used in the ill fated Graf Spee that the British severly damaged and was then scuttled in the waters of the River Plate early in the War. The Freya (named after a character in a Wagner Opera) was a mobile early-warning Radar for use in the detection of ships or aircraft. The Luftwaffe ordered Freyas, an equipment which had a range of 20km when the target was only 50m above the ground and a range of 120 km when the target was at a height of 8,000m.  The radar could be rotated mechanically through 360 degrees and it worked on a frequency of 125 mHz (2.4 metres.)   This high frequency allowed the use of a reasonably small antenna. It had however no provision for determining the height of the targets. A Freya radar had an antenna made up from a stack of dipoles which individually were only about four feet in length and the antenna array was 20 ft square and was nicknamed ‘The Bedstead’ by the German operators.  The received echoes were switched between two antenna sections, left and right and this switching was done rapidly at 75 times per second, which allowed the blips on the vertical CRT timebase to show on the right and lefthand sides, the relative strength of the blips on the left or right indicating the direction of the target.  The antenna was then turned until the echo returns were represented equally on each side. This meant that the radar was then fully beamed on to the target. This switching technique was called AN- Peilung  which meant “a radio bearing based upon the A and N system used by the Lorenz Blind Approach Landing equipment.”  Freya equipment was designated FuMG 80 (Funkmess Gerät – a radar equipment number 80.)

In September 1940 a Freya radar was coupled to a searchlight directly by using a Parastanlage (Parasite equipment, or as we would say an ‘add-on.’)

The experiment was a success and radar controlled searchlights then became a fully practical system, and many other searchlights used direct connection to Freya radars. The first British bomber shot down because of this German development was illuminated and shot down over Holland on October 1st 1940.  By then another German radar was being introduced, the Wurzburg (FuMG 62.)

More about this later, but my next installment will be devoted to the British Chain Home stations.

John Heys G3BDQ from Vital Spark published July 2007.

Return to the index of Vital Spark articles.

G3MGQ’s Month on the Air

Prepared by the clubs RSGB trainer, G3MGQ, you will find the latest DX contests including the ones to shoot for as well as ones to give a wide berth. Why not download the latest edition of Month on the Air and enjoy your DX just that little bit more.

Become a member of HERC

Join the Hastings Electronics and Radio Club.

Why not join one of the largest and most established Radio clubs in the South East of England? Very low joining cost, and free for a year to new licencees.

Vital Spark Archive

Vital Spark newsletter articles

Take a look through a large selection of articles written by club members over the years which have been published in the monthly Vital Spark newsletter .

Used Ham Radio Equipment

View HERC's Used Ham Radio Equipment for sale list..

Every four weeks, HERC's Used Ham Radio Equipment for sale list is updated on the site. Bookmark the gear for sale page to re-visit easily and take advantage of the used equipment on sale through the club.

Club Photographs

HERC Image Galleries.

Here is the official HERC photograph archive which contains multiple image galleries spanning several decades since the club was formed many years ago. Enjoy the images!

UK Amateur Radio Repeaters

UK repeaters

Click button above for full list, or a local repeater callsign below for info.

GB3EB 2m in Uckfield- Active
MB6EB 2m DStar Node in Eastbourne - Active
MB6RY Wires-X DigiGate in Broad Oak - Active
GB3HE 70cm in Hastings - Active
GB7HE 70cm DStar in Hastings - Coming soon
GB3ZX 70cm in Eastbourne - Low Power
GB3JT 23cm ATV in Hastings - NoV cleared
GB7RY 70cm X-Wires Repeater Rye - Active
GB7ES Eastbourne - DSTAR Rpt. - Active
GB3ES 2m in Hastings - Active

For a complete list of repeaters, head over to
the UK Amateur Radio repeaters list.

Popular pages

Get your amateur radio licence - Find out more about amateur radio licence training.
Month on the Air - G3MGQ's popular monthly DX contest/expedition list.
Wilf Gaye Memorial Cup - The clubs annual operating event in the memory of Wilf Gaye M0GYE.
St. Richard's College Buildathon/STEM/ARISS - HERC attends St. Richard's Catholic College for their various events surrounding the Tim Peake ARISS contact.
G3BDQ - John Hey's Rare QSL Cards.
Sussex Electronics Radio Fair - SERF Sussex Electronics Radio Fair 2016.
Vital Spark - A selection of articles re-published from the Vital Spark.
RSGB News - Find out how to get RSGB news on your mobile or PC.
Experimenters Corner - A selection of Proteus projects by Bob Gornal (G7DME)
BBADL - Bath Based Distance Learning Course.
Conquest Hospital Radio - Presented by HERC member Antony (G4CUS).
Radio Rallies 2016 - An up to date list of radio rallies scheduled for 2016.
Club QSL Cards - A selection of QSL cards the club has received over the years.
Other Newsletters - Excellent newsletters and magazines from other clubs.
TX Factor episodes - Take a look at the TX Factors YouTube videos.
John Taplin - A bio of the late John Taplin.

Amateur Radio Resources

Other Radio Clubs & RAYNET

BSARS - Brede Steam Amateur Radio Society

RAYNET - The Hastings and Rother RAYNET Group.

HERC members sites

Sigord - Gordon Sweet
Hastings Radio Comms - Andrew Haas-Campbell
Hoofbags - Liz Costa

Categories