Mk 6a Mine Detector

My thanks go to Karl Mason for kindly letting me photograph his mine detector to allow it to be included on the blog.

During the Second World War there was a desperate need for a portable method of detecting mines buried under the ground that could hold up an advance as they were laboriously located by men on their knees with bayonets. The answer came from a Polish lieutenant who had fled his native land for Britain. Jozef Kosacki designed a detector that used two coils, one of which was connected to an oscillator which generated an oscillating current of an acoustic frequency. The other coil was connected to an amplifier. When the coils came into contact with the magnetic field of a piece of metal, the frequencies were upset and a sound was heard suggesting there might be an object underneath the ground.

A number of different marks of mine detector were produced of increasing complexity and differing weights. We have previously looked at the post war Mk 4c, but this is the Mk 6a which was introduced late in the war:

The main detector had a head with an oscillator coil in it, attached to a wooden handle and with an arm brace to allow it to be held comfortably by the operator. This was attached by wiring to an amplifier unit:

The control box could be worn on the belt using the large clips at both ends of it and the headphones attached. These have a pair of rubber ear guards and an elasticated band to go over the user’s head:

In operation the detector was powered by the battery unit carried in a pack on the user’s back:

The Mk 6a has a webbing pack to hold it with a large box lid secured with a quick release tab:

Shoulder straps are fitted to the rear of the pack with hooks to allow it to be attached the 37 Pattern webbing:

Note also the waist strap to help distribute the load better. The total weight of the detector was under 30lb and could be easily handles by one man. Over the course of the war a total of 100,000 detectors of the different marks were produced and used by British and Commonwealth troops.


  1. You keep sparking old memories…that’s not fair, I’m old and I have too many ๐Ÿ˜‰

    I remember taking training on metal detectors during an advanced EOD course about 30 years ago, presented much better and far more indepth than on any previous course I’d had before or since.

    There were a number of training areas so several operators could work at once with various bits of shrapnel and odd shaped metal things scattered around as well as a few ‘target’ items such as shells, mortars, mines, etc. to locate and mark out the size and shape of.

    Most times you could tell what you’d ‘found’ and be quite accurate after a little practice in reading the signal meter and putting markers down to get a very good outline and an idea of depth.

    There was one rather annoying student (there’s always one, sometimes it was me ๐Ÿ™‚ ) and his area was giving him fits trying to get any useable readings and you could see the frustration building.

    I was standing off to the side next to one of the instructors and asked him what they’d done, since it was pretty obvious from the look on his face that this was a set-up.

    He laughed and answered “Buried a Buick”
    There wasn’t much else to be said so we just stood back, lit smokes and watched the show.

  2. The 6A is essentially a reduced-size 4A (with an improved search coil) intended for beach landings and paratroops. The battery is much smaller than the one used by the 4A, so has limited life. I’ve got most of a 6A outfit – missing some of the webbing (which I think is all custom to the unit) – the backpack is “Satchel, Signals, No.12” officially, despite not looking anything like a satchel. (I must get it working so I can locate the route of the power cable to my shed – put in before I bought the place.)

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