Comments on: Echoes From The Sky

Echoes From The Sky

basicchannel — Thu, 07 Apr 2005 23:52:53 -0800

First built in the 1920's, and predating the use of Radar in World War II, early warning "sound mirrors" were used to provide some means of detecting incoming enemy aircraft. First used in World War I to listen for Zeppelins, their vestigial remnants dot the English coastline. The bizarre legacy of the sound collectors lives on through some decidedly nerdy enterprises.

By: trinarian

trinarian — Fri, 08 Apr 2005 00:11:16 -0800

Militaries today need passive detection systems. Radars can be isolated and destroyed pretty easily. ALARM and HARM missiles are designed for this, traveling at extremely high speeds towards the source radiation. I'm surprised third world countries don't employ some form of the portable systems. It wouldn't work against aircraft, but it seems effective against low flying cruise missiles that could be stopped with a wall of AA fire if this stuff is really accurate to within two degrees. Fascinating stuff, basicchannel.

By: kickingtheground

kickingtheground — Fri, 08 Apr 2005 00:12:40 -0800

Awesome post.

By: sourbrew

sourbrew — Fri, 08 Apr 2005 00:25:01 -0800

Thanks, I'm enchanted. This one in particular has peaked my interest. I want to see a pic from inside the house.

By: three blind mice

three blind mice — Fri, 08 Apr 2005 00:52:48 -0800

outstanding post basicchannel. interesting, obscure find, well reseached, and nicely presented. i'm surprised these things are not still in use - patched, repaired, and kept in service long past reason - like everything else on this island.

By: Rothko

Rothko — Fri, 08 Apr 2005 03:06:08 -0800

It wouldn't work against aircraft, but it seems effective against low flying cruise missiles that could be stopped with a wall of AA fire if this stuff is really accurate to within two degrees. How would a sound mirror work as a defense against any object travelling faster than the speed of sound?

By: TwelveTwo

TwelveTwo — Fri, 08 Apr 2005 03:31:09 -0800

I wonder what a zeppelin sounded like through one of those.

By: silence

silence — Fri, 08 Apr 2005 04:18:47 -0800

You might want to have a look at : soundMirrors.org A bit of a self-link but that's allowed as long as it's not a FPP isn't it ?

By: Jimbob

Jimbob — Fri, 08 Apr 2005 04:58:40 -0800

How would a sound mirror work as a defense against any object travelling faster than the speed of sound? You could hide behind it. They look pretty solid.

By: raygirvan

raygirvan — Fri, 08 Apr 2005 05:04:13 -0800

More pictures and details: Listening Ears, Greatstone, and Lade Mirrors. silence: good site, and I also like the Black Shoals, but really, the Internal Communication Amplifier confirms my worst prejudices about contemporary art.

By: silence

silence — Fri, 08 Apr 2005 05:54:17 -0800

raygirvan: you're allowed to laugh, you know.

By: madamjujujive

madamjujujive — Fri, 08 Apr 2005 06:28:44 -0800

wonderful post - five stars, basicchannel!

By: Busithoth

Busithoth — Fri, 08 Apr 2005 06:37:10 -0800

This is great.

By: GhostintheMachine

GhostintheMachine — Fri, 08 Apr 2005 06:54:21 -0800

Pardon my ignorance, but how do you reconcile "First built in the 1920s" with "First used in WWI", which ended in 1918? Great find, regardless.

By: raygirvan

raygirvan — Fri, 08 Apr 2005 07:09:25 -0800

raygirvan: you're allowed to laugh, you know. Oh, I did. Out of interest, how's the project for the new mirrors going? The physics of it looked a bit borderline to me.

By: glider

glider — Fri, 08 Apr 2005 07:24:32 -0800

If this interests you be sure to visit The Museum of Retrotechnology (which I'm sure has been mentioned here before).

By: petebest

petebest — Fri, 08 Apr 2005 07:39:23 -0800

excellent post. I had no idea . . .

By: basicchannel

basicchannel — Fri, 08 Apr 2005 08:44:52 -0800

GhostintheMachine: Good catch. WWI is actually correct, however, the linked site delivers up that nugget of disinformation(!!!zomgilluminati!!!). Yes, I blame internets.

By: odinsdream

odinsdream — Fri, 08 Apr 2005 08:45:58 -0800

You might want to have a look at : soundMirrors.org Great site! Picture C2 is straight out of a Dr. Seuss book.

By: brownpau

brownpau — Fri, 08 Apr 2005 09:04:31 -0800

Wow, fascinating stuff I never knew about before today.

By: safetyfork

safetyfork — Fri, 08 Apr 2005 10:14:23 -0800

Great post, and excellent tag: cleverhumans.

By: breezeway

breezeway — Fri, 08 Apr 2005 13:56:26 -0800

Wow, that's great. When I was a kid, my brother and I built something along these lines (from a book of scouting projects) so we could listen to our neighbors fuck.

By: tkchrist

tkchrist — Fri, 08 Apr 2005 13:56:52 -0800

Cool. When we were stationed in England I always wondered what those were. So, if your mate was a sound mirror operator, you can guess what the popular practical jokes of the day were.

By: pracowity

pracowity — Fri, 08 Apr 2005 14:41:18 -0800

A bit like whispering galleries.

By: Substrata

Substrata — Fri, 08 Apr 2005 14:44:31 -0800

great post

By: raygirvan

raygirvan — Fri, 08 Apr 2005 17:31:00 -0800

Pardon my snarkiness - there's no doubt that this is historically fascinating - but does anyone have any thoughts on the practicality of the new mirrors by Autogena et al that supposedly will allow cross-Channel communication over 25 miles? Looks to me like one of those artistically interesting but physically unfeasible projects.

By: silence

silence — Sat, 09 Apr 2005 10:45:39 -0800

raygirvan : I'm not directly involved with the new mirrors project (the project is mostly the work of Lise Autogena, who I often work with), but as far as I can tell it's moving on slowly, despite some fairly gruelling bureaucracy. There should be a new website and booklet coming out about it soon, I think. The audio transmission for the new mirrors isn't done acoustically - as you point out that's pretty difficult. Though, we did actually work out a way that it might have been done acoustically at one point, but it would have been very, very technical and probably a bit of an environmental hazard (it involved transmitting the sound underwater, rather than through the air, and I don't think the fish would have enjoyed it).

By: raygirvan

raygirvan — Sat, 09 Apr 2005 15:50:01 -0800

Thanks for the details. It'd be neat to do it over a shorter distance somewhere high-profile - maybe over the Thames, where it could work acoustically (like the one over the Royal Military Canal at Hythe).