PSS-11 Detecting Set, Mine

© Brooke Clarke, N6GCE

 
Fig 1
Fig 2
Fig 3
Fig 4
Fig 5 
Fig 6
Fig 7

Description

As the metal content of land mines has gone down (replaced by plastic) the need for a mine detecting set that's very sensitive has developed.  The PSS-11 was designed to be very sensitive in it's day .  It was replaced in the early 1990's by the PSS-12, which is the current issue mine detector set.  The goal is to detect a very small metalic firing pin in an otherwise non-metalic land mine.

The PPS-11 works by nulling out a 2,500 KHz audio tone.  When this is really nulled you will hear nothing when there is no metal present.  A problem with early production PSS-11 (audio module is solid Yellow) this is that if the battery goes dead while the detector is in use there is going to be no indication to the operator who may die.  Later versions of the PPS-11 (audio module is Yellow with a Black stripe) have a tone warning of low battery.  The PSS-12 makes a clicking sound while operating rather than silence.

Note that the PSS-11 and PSS-12 are not good for treasure hunting where there are many man made metal parts in the ground, like at a fair ground.  They would be good for looking for gold nuggets in wilderness.  Since my back yard is forest, I should be able to find underground pipes (plastic with marker wire) or maybe who knows?

Fig 1 - This is the equipment that goes into the field.
Fig 2 - Bottom of the shipping container showing spare modules on the left and the phasing block in the upprt right.
Fig 3 - The cold temperature battery holder is in the lid of the shipping cntainer.
Fig 4 - The controls, "X" knob on the top and the "R" knob is to the right.  The Switch has positions:

Fig 5 - the electronics box that also holds the batteries
Fig 6 - the electronics box with the cover removed aslo showing the top (+) end of a CR123 battery.
Fig 7 - the A5 board

The PSS-11 ships in it's own transit case.  Overall PSS-11 Set photo, Spare Modules and varometer phasing test block in transit case bottom, exteranl battery adapter in lid

Operation

The PSS-11 picks up the metal eyelets in my otherwise nonmetallic shoes.  I need to find metal free shoes to use.
The canvas bag for the electronics unit is made to attach to a standard army ammo belt.  You need an ammo belt to hold it.
Holding the long handle of the sensor is difficult, there must be a technique to make this easier.

FM 20-32 MINE/COUNTERMINE OPERATIONS, 29 MAY 1998 - Appendix F (Mine Awareness) has operation info for the PSS-12
GTA 5-10-34 CONVENTIONAL U.S. LAND MINES, 04 JAN 1995
GTA 5-10-37 MINE CARD, PART 2, 28 MAY 1997 = restricted
GTA 5-10-38 COUNTERMINE IDENTIFICATION TRAINING (CIT) PROGRAM, 17 JUN 1997  = restricted
GTA 5-10-44 MINE AWARENESS (SANDI), 01 MAY 1999  = restricted
TC 20-32-3 FOREIGN MINE HANDBOOK (BLAKAN STATES), 15 AUG 1997   = restricted
TC 20-32-4 FOREIGN MINE HANDBOOK (ASIA), 15 AUG 1997   = restricted
TC 31-34 Demining Operations. 24 September 1997
FM 90-13-1 Combined Arms Breaching Operations. 28 February 1991 Appendix B has some mine data

Battery

The original battery was a 10.4 Volt Mercury type BA-1389/U and for environmental reasons all Mercury based batteries have been discontinued.  Since Mercury batteries have a problem with cold, the PSS-11 has an optional remote battery container so that the battery can be placed inside the operators clothes to keep it worm using body heat.

A simple replacement is to use 4 each CR123 Lithium Photo Batteries (Radio Shack 23-155) that provide 12 Volts and just drop in.
Slide into the tube negative end first, i.e. the positive end touches the cap (positive ground).  I have tried these batteries and they work.

Manuals

Troubleshooting & Adjustments

The A5 board (Fig 7)has the sockets for the plug-in modules and connections for the headphones, coils, battery, etc.
Notice the hole in the sheetmetal at the A2 module used for the variometer phasing adjustment.  In additon to the variometer phasing test block that is part of the set the manual has a procedure to test the phasing using an 30 calibre M1 carbine round pushed into the dirt bullett first.  The PSS-11 should detect two distinct peaks with the coil 6" above the ground.

The main chassis has 15 numbered test points on the A5 printed circuit board.  You can see 13, 14 and 15 in the scan, most of the others are under the cable.
TM 5-6665-202-13 has Table 6-1 Resistance measurements and Table 6-2 Voltage measurements for these test points.
The schematic diagram is Figure 1-2.

Demining

All water type mines have a scuttling feature so that after a programmed amount of time they deactivate and sink.  This is only true of a very small proportion of land based mines.  This causes large areas to be rendered useless after the hostilities cease where land mines have been deployed.  There are a lot of people who suffer from these left over land mines.  See my Demining web page for more on this.

Links

Schiebel - AN-19/2 Mine Detecting Set (Military PSS-12) -
AN/PSS-11 Mine Detector by Mark Blair
Lone Mountain Electronics - Military Mine Detectors - PSS-11 - General PSS-11 Information.pdf -
US Marine Corps Fact File - AN/PSS-12 Metallic Mine Detector -
Surplus Stuff by Lee Frank - EQP-002 - is PSS-11 set
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