Metox detection by ASW

[vanjast]

Diverted into another book store on my rounds.. and I pulled what seems to be a gem. --- Conflict over the Bay

The book looks brand new... maybe someone can confirm these details.

It's basically interviews with WW2 British ASW crews and their experiences over the Bay of Biscay. An interesting point on Pg27 was about the Metox radar detector used by the Uboats.. saying that the ASW aircraft could detect it and home on the sub.

I'm an older electronics guy and never thought of this until they mentioned mixing frequencies... and thought.. ZAP .. This must be correct... a quick search.. and here it is
https://en.wikipedia.org/wiki/Superheterodyne_receiver

Check Local oscillator radiation at the bottom of the page
:D

[WilhelmSchulz.]

I still find it hard to belive that a radar detector gives our RF waves. :06:

[vanjast]

The basic story
The receiver mixer stage, which helps ID the required signal, is powered an oscillator... which is essentially a transmitter.
In old electronic systems, the mixer stage was 'directly' coupled to the aerial receiver, so it's signal frequency would be inadvertently transmitted.

All you needed was a receiver to pick up the mixer frequency... and the Brits were wise enough to know this....
The Germans also knew this.. but again they under-estimated the British know-how.
:hmmm:

[banryu79]

So you got a Radar-detector and then a Radar-detector-detector, and then a Radar-detector-detector-detector... lol :haha:

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

P.S.: Amazing the "never-heard-before" stuff I learn from this forum by just randomly read some threads about a videogame :)

[UKönig]

I prefer Electronic Counter Measures and Electronic Counter-Counter Measures myself...

[Marcello]

According to some sources while homing on Metox was perhaps possible it was not actually done. Rather the information was used to mislead the germans in order to downplay the effectiviness of radar detection.

[vanjast]

Interesting book..
New weapons around June 1943

1) Describes the use of 'solid head' rockets (June 1943) which are aimed to hit the water at about 30 feet from boats beam... the rockets then went right through the UBoat Hull.. completely through the boat, coming out the other side.

2) Another weapon was 35 pound shaped charge 'bomblets' dropped in sticks of 72. Essentially an aerial hedgehog = instant sinking.

3) Small homing torpedoes.

[Kielhauler1961]

...3) Small homing torpedoes.

These nasty little things were called FIDO (U.S. Mark 24 mine) and were air-dropped into the swirl of a rapidly escaping U-Boat. Although slow they were faster than a submerged conventional submarine and it wasn't there to fetch your slippers. 204 were used sinking 37 U-Boats and damaging 18 more - an effectiveness rating of 22% (compared to 9% for DC's).

Many times I've sweated-out the anxious minutes after a crash dive due to an aircraft, just waiting for one of these things to catch-up and put an end to me...:gulp:

KH

[CCIP]

Interestingly, I read the opposite - that many German commanders were overly-concerned about the Metox giving away their position and refused to use it, which only made them more vulnerable to aircraft. I'm not aware of any incident where Metox intercept led to a u-boat being sunk. On the other hand, it's definitely true that dozens of boats were sunk because their commanders underestimated British electronic capabilities. But that was mostly to do with radar and passive RDF (picking up ordinary radio signals).