Monday, August 27, 2007

With Extreme Prejudice...

I came across the following comment to a post Lex put up yesterday from MaxDamage, quoted here in part:

Second act: fishing for dogs. First procure an electric fencer or something similar that has a nice voltage level (10K volts minimum) and wire it to a garbage can (metal, not plastic). Allow the remaining cats to investigate and learn to avoid. Replace the fencer with the stripped leads on an extention cord, invert the lid, fill with water, and place some old meat on a brick in the middle of it. 10K volts stings. 110vac at 15 amps hurts. 220vac at 40 amps kills. If you elect to do the 110vac routine you will be rewarded with yipping sounds in the middle of the night. You will then be able to roll over and sleep the sleep of the just and rightous.

Despite the wording in Max’s first line, this suggestion is all about “How to Kill a Coyote,” specifically a murderous coyote or coyotes that terminated one of Lex’s household pets with extreme prejudice. And a rather inventive way to dispatch said coyote(s), I might add. Which brought to mind a similar varmint-eradication activity I undertook many, many years ago, albeit with much smaller prey and much higher voltages.

The place: Lompoc Air Force Station.
The place, more specifically: The AN/FPS-67 search radar tower at Lompoc AFS.
The time: c. 1965, or ‘66, or maybe even ‘67.
The time, more specifically: Mid-shift…around 0230 ~ 0400.
The story:

My place of business, the search tower at Lompoc AFS, was over-run with mice at one point in time. Which isn’t much of a problem in an industrial setting, but it is somewhat irritating, none the less, to brown-baggers who, when lunch hour arrives, retrieve their lunches from the bookshelf, work bench, or other such non-secured storage places only to find small holes nibbled in said brown-bags and their contents. To make a long story short, many attempts were made by the occupants of the search tower to eliminate these little furry bio-hazards, consisting mainly of common ordinary mouse traps, which worked only to a limited degree. In other words, although there were casualties aplenty, the mice still managed to occupy the search tower. In force.

So it came to pass that YrHmblScrb, on duty in the wee small hours of the morning, his assigned work for the evening completed and the radar humming along with no difficulties, decided to work on the mouse problem and have a little sport at the same time. Hi-tech sport. High-voltage sport.

Radars, by definition, are high-power, high-voltage systems. The transmitter sub-system uses literally thousands of volts to produce pulses of energy which are measured in megawatts of power. The heart of the transmitter is a klystron tube, which sits atop a pulse-transformer, which is filled with insulating oil to prevent thousands of applied volts from arcing within and between contacts, which electricity is prone to do. The insulating oil, like all oils, has a finite life and breaks down over time, losing its insulating properties and, if left to deteriorate, will result in arcing within the pulse transformer and the loss of rather expensive radar parts. Not to mention downtime for the entire radar which was highly frowned upon, being said radar was the first line of defense against air attack, and all. One tests this oil and drains and refills the pulse transformer (a very nasty, dirty job) when the oil is no longer “within specs.”

Checking the oil to ensure it’s within specifications is a standard preventive-maintenance routine and there is a specific item of test equipment used to test said oil. This item of test equipment (a much earlier version of this) was basically a ten-inch cube with a large transformer in its base to generate high voltage, a removable bakelite cup (with large brass electrical contacts on the inside) that sits in between two spring-loaded contacts at the top of the box, and a manual rheostat that varied the voltage applied to the cup. One takes a sample of the oil from the pulse transformer, puts it in the small removable cup, switches on the box, and increases voltage until the oil breaks down and arcing occurs through the oil in the cup. You can either vary the voltage continuously until arcing occurs, or set the box to a given voltage and press a button to see if arcing occurs at that particular voltage. The minimum insulation spec for the oil is 35 thousand volts, the tester could generate up to 50 KV, if memory serves. Are you beginning to see where this is going, Gentle Reader?

So. I get the oil checker out of the test equipment locker and set it up on the work bench. Then I got a 20 foot (or so) length of RG-59 cable…coaxial cable, with inner and outer conductors…and stripped both ends of the cable, separating the inner and outer conductors by a wide margin. I connected the center conductor to one contact on the oil checker and the braided wire outer conductor, which has been “combed out,” to the other contact. I then ran the RG-59 across the floor and over to the desk, a distance of about 15 feet or so, looping the cable across an overhead cable rack so that the end dangled just above said desk. Once again, I “combed-out” the braided outer conductor and arranged its wires under two or three damp paper towels on the surface of the desk, leaving remainder of the wire (the center conductor) hanging about an inch or two above the paper towels. I baited the center conductor with a small piece of lunch meat (from my lunch, obviously), turned out the lights, and retreated to the work bench to await my first victim. Which wasn’t all that long of a wait…

It took several attempts before I got it right. I had to make minor adjustments to the distance between the RG-59’s inner and outer conductors on the desk, and figured out that I couldn’t twist the oil checker’s rheostat fast enough to get the mouse before he realized he was being had—I had to set the oil checker's voltage at “max” and press that little red button for an instantaneous jolt o’ juice. And there were more false starts, but… you get the picture: trial and error works. And those mice did the most amazing double-back-flips and other sorts of gyrations when I zapped ‘em, not to mention the bright arc of discharging high-voltage through their little scum bodies. Very satisfying, to say the least.

I think I got four or five mice that evening, all told. Not a very effective way to kill mice, but a highly entertaining method…at the very least. I managed to reduce the mouse population that evening, but failed to eliminate it. We remained plagued with mice for as long as I was there.


  1. I'm going to have to keep this in mind for our little rodent problem. I think I got them all out of the house. But until my new doors come in to enclose my garage, I'll be stuck with them (and rattlesnakes) out there.

    Now, I wonder what is that thing/s I hear in the attic. Hubby heard it this morning for the first time and it freaked him out!

  2. Great story, Buck. Lots of strange things go on during the wee smalls of the mid watch. Brings back a few memories.

  3. Ha, Ha. I used ours to kill flies. Same basics 'cept I made a metal grid.

  4. Drats ... not exactly a 24/7 fix when you are off the grid but the dial-in experiments sure sounded like fun. If you had used peanut butter, they would have stampeded you and browned out the base.

  5. Lin said: ...but the dial-in experiments sure sounded like fun.

    Ah, they were! I left a lot of that stuff out..."brevity," and all that. One of the minor details was that I only got one "shot" at the mice, because of the way the oil checker worked. Which is to say I had to wait a minute or three for the capacitor in the oil checker to recharge before I could zap the target again (assuming I'd "missed" on my first attempt)...and by that time the mouse was long gone.

    And so forth and so on...

  6. Techno-mouse killer - sounds kind of nerdy - I like it.

  7. I used to stand quaterdeck watches back when I was in the Navy.

    Late at night,our favorite sport, to keep alert, in a forign port, late at night, was rat hunting.

    Weapons of choice were the .188 pellet gun and a wrist rocket sling shot. Personal best was 18 kills and 25 probables on one midwatch in Karachi Pakistan, spring of 85.

    Sure sounds like fun zapping the little Btards though!

  8. Unkawill sez: Personal best was 18 kills and 25 probables on one midwatch in Karachi Pakistan, spring of 85.

    Dang, Unkawill, that's some sharp-shooting!! Especially with a wrist-rocket!


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