Cordon Sanitaire: Electronic Alarms and Monitoring

August 25, 2014

If I thought that getting historical background to Cordon Sanitaire defoliation efforts (see previous post) was challenging, I was wrong!

Trying to find anyone who has in-depth information on the electronic early warning systems installed on the fences was an even more daunting task. To be very honest I am not in any way convinced that what I have managed to find holds too much water and this is once again where I will be hoping that someone, somewhere reads this post, tells me I have written complete rubbish and puts things right. I can take it and no offence will be taken I assure you. We simply need to get this as factual as we can. There has to be Rhodesian Army veterans that actually installed and monitored the electronic side of things that can help here.

The following redaction comes from more than one source, the reliability of which has not been confirmed to me. From an intelligence source and reliability perspective I therefore have no option but to rate it as F/6 (Insufficient information to evaluate reliability. May or may not be reliable/The validity of the information cannot be determined) and should therefore by no means be quoted as being the way things actually were. Read on………..

For the sake of simplicity we will consider the Cordon to be 25 metres wide, fenced on both sides, and containing anti-personnel blast mines.

On the home side a system of electronic sensors divided into monitored sectors and wired to sector control boxes formed the basis of the early warning system. I have not been able to find any information as to what type of sensors (movement, vibration, broken electrical circuit, audio, etc.) were used, nor who was responsible for installing them (possibly the Rhodesian Corps of Signals (8 Signal Squadron)).  According to one source these control boxes were placed in bunkers close to the home side fence and manned full-time by troops waiting for an alarm to be set off.

Logic makes me think that a combination of activation triggers may have been used. Apparently the idea was that any penetration of the Cordon would be detected by detonations or some form of electronic sensor. My information claims that reaction to these events was primarily by vehicle and took place within 10 minutes of a signal being received. In addition to the vehicular response, artillery fire was also used to put down fire on ranged, pre-selected targets. I imagine this would be from 25 pounder howitzers or possibly 120mm mortars.

It is my understanding that the only parts of Cordon Sanitaire to be fitted with an electronic early warning system were the Musengezi/Mukumbura, and Nyamapanda to Ruenya minefield. Soon after these areas were completed a significant amount of false alarms were being recorded. This resulted in finding no enemy presence at the alarm trigger point. Due to the significant cost of ammunition being expended on these false-positive events, it was decided to curtail the rapid response on these areas in 1975. An ongoing Cordon Sanitaire review shelved the whole idea of an early warning system shortly thereafter.

And so ended the Cordon Sanitaire early warning system.

I do not know how effective these measures were as I never encountered them during my time serving in the Rhodesian Corps of Engineers. Personally I do not think the electronic system was as successful as the planners initially thought it would be and with the Rhodesian economy heavily burdened by sanctions and an ever-increasing defence budget there was little chance of any project surviving unless it showed significant success indicators (body count, infiltration mitigation, etc.).

I located the following on the website.  They seem to confirm in some ways parts of the foregoing:


I will continue to seek further sources to help unravel this interesting and little known subject.

Please also have a look at my website dedicated to Rhodesian and South African Military Engineers.  Please join us on the forums by using the following link:


© Mark Richard Craig and Fatfox9’s Blog, 2009-2014. Unauthorised use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited.

6 Responses to “Cordon Sanitaire: Electronic Alarms and Monitoring”

  1. Chris said

    Would you consider drawing on your own experience as you write these articles? In other words, just write about what you did after your experience laying mines Rhodesia. No need to write a textbook on the mine laying. I anticipate that you have some very interesting experiences to relay and I look forward to hearing from you. Some of us don’t need the technical parts. I was drawn to your column by the personal interest. Look forward to the next posting mate.

    • fatfox9 said


      Thanks for the comment. Some people do want to know and understand the technical side of the work we carried out, so the easy answer is that I will continue to write as I am for now. What I will say is that the Cordon Sanitaire was the Rhodesian Corps of Engineers own war within a war and that makes it very special to those of us who served. I concede we are a little bogged down at present and this chapter is indeed taking longer than I thought it would but we will soon move on and I will indeed write of my own experiences and those of others. There is a long way to go and there are many interesting posts to come. I trust that you will continue to visit and it is always good to get feedback from those who pass by.

      All the best and hang in there with me. I will not disappoint you.


  2. John (Aussie) Austin said

    There were NO electronics between Nyamapanda and Ruenya. It was a straightforward three-lane plough-shear and AP mine laid field,…. in a non-defoliated field. The normal home fence was erected by Tse-Tse Dept, whilst the enemy side had a single strand of Barbed Wire with mine triangles.

    Safe-Lane 13 (between Nyamapanda base and Mudzi sub-base) was a regularly breached point….. where we eventualy achieved a kill of 6x by double-bluff dusk ambush on one of my call-ups.

    The CTs had a pretty good Sapper of their own in this sector.

    2Engr – RhE

    • fatfox9 said

      Thanks for your input Aussie. Always good to hear things from a different angle, although I will leave the post as is for now. Well done on the 6 gooks!

  3. donald munroe said

    Thanks Mark , all ways interesting , please keep it up.

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