Battle of the Beams

8/3/2026 at 11:17:12 PM

For those interested in this topic I can’t recommend the following book enough.

https://www.goodreads.com/en/book/show/1127842.Most_Secret_W...

Many of the overarching themes and challenges of dealing with technical problems where you have incomplete information will be familiar to many here.

According to the publications section of his Wikipedia, the book is available for free on archive.org. https://en.wikipedia.org/wiki/Reginald_Victor_Jones

by hi_hi

8/4/2026 at 7:27:01 AM

Seconding this recommendation, a fascinating read. Also full of amusing - or not so amusing - side stories. Like at university in the 30s, they had a visiting scientist over from Germany. For a laugh they implied that a Jewish colleague of theirs was, some kind of political activist maybe? I forget exactly, but in documents after the war Jones found his name on a list of known subversives to be captured for interrogation in the event of an invasion of Britain.

Or how in interrogations after the war, a senior German officer haughtily refused to speak to Jones, assuming that "Dr Jones" was a generic false name, and only relented after he proved this was in fact his real name.

Or how they sent a radar engineer on a commando raid to France, to dismantle German equipment and return with it. Jones attempted to get him commissioned into the Royal Engineers, to disguise him from special interrogation if captured, but military beurocracy stalled, so the man went as a civilian (and the raid succeeded in the end).

But the meat of the book is of course the beams, and how Jones and his team were able to identify the technology behind the Luftwaffe bomber navigation methods, and spoof them in order to help the bombers drop their bombs in the sea or on unoccupied farmland. You're struck by the total focus and dedication of these scientists, and their brilliant deduction (helped at times by German poeticisim, such as naming their one-beam system Wotan, after the one-eyed god).

Jones left government service at some point after the war, to take up a professorship at Aberdeen university, but he did return to Intelligence at Churchill's request in the 60s. He also wrote a book about that experience, which I didn't finish, but his impression was that, where Intelligence in his time had been something of a gentleman's game, nowadays it was a seedy and cutthroat affair, conducted by persons of low morals.

by backhold

8/4/2026 at 12:17:29 AM

This is such a fascinating piece of history.

I've always been very interested in the developments that occurred in WW2. I think The "Battle of the Beams" is one development that gave us the basis for what we use so much now in general aviation.

The BBC series "The Secret War" is a fantastic series that pulls apart how these discoveries were made. It has a lovely 1970s vibe to it and is very well narrated.

https://www.youtube.com/watch?v=fkCW4g8It_A&list=PLV7OedKrXD...

Interesting to realise that the cavity magnetron, providing higher resolution radar, was invented by the British and gifted to the United States. I believe the Germans researched it, but decided it was impossible. Please correct me if I'm wrong on this though.

If you watch "Greyhound", the tools that sunk the U-boats were British inventions, hedgehog and ASDIC. HuffDuff (High Frequency Direction Finding) is mentioned I think in the movie? It was made by a Polish engineer working for the British. Amazing that the Kriegsmarine didn't work out that their mandatory reporting schedule was sinking their U boats. With such a collection of defenses combined with doctrine changes for attacking U boat swarms, no wonder the U-Boat losses became so huge.

WW2 changed the world and brought us forward so much in terms of technology. Fascinating stuff.

It's a great place to explore the physics of it all, since the tools used were sometimes elementary (X-Ray machines to baffle direction beams).

Reginald Jones changed the world. Thanks hi_hi for the links.

by kreelman

8/4/2026 at 1:20:50 AM

The BBC "Secret War" series and RV Jones' books are superb. I would recommend also reading his "Reflections on Intelligence" - it was written later and is slightly more philosophical. By that time Jones had been burned by bureaucrats - he compares his small efficient wartime office to the post-war bloat.

The BBC series is really good. They don't make documentaries like that anymore. The "Still Secret" episode on Enigma is easily the best coverage of how the system worked, was cracked and the organisation behind it. There is also an accompanying book, which has many more details.

>I think The "Battle of the Beams" is one development that gave us the basis for what we use so much now in general aviation.

Actually it started the other way around. The beams were based on pre-war blind landing Lorentz system.

by RachelF

8/4/2026 at 11:27:33 AM

Ah, thanks. As I think about it, you're right. There was a Lorentz landing system in bombers that was far too accurate for just landing. Intelligence gathering extracted that from the crew's conversations. That was how they hid their direction finding... But the system already existed.

I think I got confused with radar, but radar isn't beams as such.

by kreelman

8/4/2026 at 12:48:40 AM

My thanks to you @kreelman.

I have not seen these documentaries before. Indeed I had not seen video footage of RV Jones before. As a lifelong hero of mine, I’m looking forward to watching these in their entirety.

I’m currently in the process of reading Churchills autobiographies. While quite heavy, he writes with such clarity and knowledge. It’s a great account of how WW2 came about, and articulates how easily it could have been avoided if only a few people in positions of power had made different choices.

How different our world and technology could be if not for those terrible circumstances of war.

by hi_hi

8/4/2026 at 11:34:46 AM

Glad you'll get to watch them.

RV Jones was pretty incredible. From the interviews you get a bit of a picture of his initial attempts at getting his points across. He was persistent and knowledgeable.

Indeed, it's a shame that war brought us so many advances...

by kreelman

8/4/2026 at 12:20:51 AM

Somebody, either Buderi or Rhodes has the magnetron appearing in the MIT Radar labs and somebody saying "oh, thats obvious" and being asked "ok smartass, how does it work then..."

Sometimes, simple things are obvious in hindsight.

by ggm

8/3/2026 at 11:55:55 PM

Decca navigation gear was common in British boats operating in near coastal waters right up to the 70s and 80s. The fundamentals of how this system worked were not radically different to the beam systems used for navigation in the war.

https://en.wikipedia.org/wiki/Decca_Navigator_System

Loran and then GPS competed and replaced.

Robert Buderi's book on Radar is an amazing read to one side of this, it drives all the way through to VLSI. Fascinating stuff.

https://books.google.com.au/books/about/The_Invention_that_C...

by ggm

8/4/2026 at 2:30:21 AM

I had some exposure to Decca, we mainly got by with early Loran (less accurate than Decca), then transitioned to Loran-C (better accuracy) in parallel with reverse engineered NavStar, then onto early civilian GPS with home grown base stations and post processing .. and some time ground truthing older maps to the newer WGS ellipsoid standards.

by defrost

8/4/2026 at 5:12:44 PM

> When Jones mentioned the possibility of bombing beams to Churchill, he ordered further investigation. The British codenamed the system Headache.

> [...]

> Efforts to block the Knickebein headache were codenamed "Aspirin".

Love it.

by nolist_policy

8/4/2026 at 1:18:37 AM

What a wild, fascinating and, as a Brit, a rather satisfying read.

So much luck, intelligence, perseverance and engineering.

I believe still today we have some of the world's finest radar and navigation tech etc?

by gib444

8/4/2026 at 2:38:40 AM

The US, UK, AU, and Russia have been back and forth on leadership relative to some metric or another wrt Over the Horizon systems throughout the post war period.

> the world's finest radar and navigation tech

Hadn't realised the UK had a sat nav constellation up (nav tech) and .. are we counting Starlink as radar tech?

* https://en.wikipedia.org/wiki/Over-the-horizon_radar

* https://www.youtube.com/watch?v=jbp3kdJZ1_A

by defrost

8/4/2026 at 8:21:02 AM

There's no chance Starlink doesn't have some extra military payload.

by inigyou

8/4/2026 at 12:05:19 AM

> The Germans became convinced the British had somehow learned to bend radio signals.

I love learning about theories like this from less advanced times. Feels like a taste of a simpler world.

by LoganDark