Home of the Fence Hawk

For both Human & Livestock Security
Animals In and Humans Out

Fence Hawk Voltage Monitor & Fence Phase Equalizer

FENCE HAWK … fence voltage monitor and alarm

          False alarms are the absolute bane of any security system or device. Rogue pulses from a vast variety of sources included lightning and extraneous voltages of all kinds from more sources than you can think of. Your high voltage fencing is a huge antenna which collects more pulses and signals of all types than you can imagine. The Fence Hawk is the only high voltage fence voltage monitoring which has the built-in intelligent circuitry to filter out events that are not an actual intrusion.

          The only “reporting” stand-alone high voltage fence voltage monitor that is consistently accurate, continuously measures and reports the real time status/voltage of your high voltage fence. The Fence Hawk measures the actual fence voltage that exists on your fence and ignores the noise that causes false alarm on most security fence systems. This is a modern device designed and developed specifically for high end reliable security.

           The Fence Hawk does not need to resort to vibration sensors, infra-red beams, etc. to maybe verify a possible intrusion. Another common practice is the “central station cutout” where the central station calls an middle man to listen in to verify an actual intrusion. One could short the fence and put through a dozen intruders while the cutout person decides there was no intrusion as the fence was now reading back to normal.  Since actual intrusions are rare the middle-man almost always never reports this loss of fence voltage while literally dozens of people could have entered your property.

           The voltage divider is to hang on the bitter end of the high voltage wire at the end of the fence. This completes the continuous high voltage loop starting at the fence charger, continuing back and forth along the fence along the high voltage wire to the voltage divider.

           The voltage divider provides a low voltage signal from the fence to the Fence Hawk which can be remotely located in a building or other enclosure separate and away from the high voltage fence. Within 1 yard or less a twisted pair of phone wire works to provide a continuous connection to the high voltage fence charger. We suggest a 12 gage twisted pair when you remote the Fence Hawk a hundred yards/meters or so distant from the high voltage fence line. The gage of the twisted pair connecting depends on the distance the Fence Hawk is from the fence.


          High voltage electric fences (5kv – 15kv, “kilovolts”) are utilized all over the world for both humans and livestock. When the fence charger utilized puts out a voltage pulse that is about 1 joule or less (around 5 – 10 micro-seconds duration pulse) the pulse developes some radio frequency characteristics that have to addressed. These characteristics do not occur with the higher joule fence chargers.

           This voltage reduction only becomes a problem when a low joule fence charger when the high voltage fence is installed adjacent to a steel fence, usually a chain link fence. When the low joule fence (usually less that 1 joule output) and when installed adjacent to a steel fence) you will experience a measurable reduction in rated output voltage. All 12 volt battery powered chargers available are less than 1 joule output. The high voltage output pulse is short enough that it has some high frequency characteristics that can reduce the effective voltage as much as 50%. These changes are not present in higher joule fence chargers as their longer pulse width effectively drops them out of, and below radio frequencies.

           This drop of voltage of the high voltage pulse can be avoided by compensating for the capacitance that exists between the high voltage fence and the steel chain link fence. One can offset this capacitance by putting an inductor on the fence and experience no loss of fence voltage without using valuable yard space. Ask for information regarding the EQUALIZOR which usually costs plus-minus UD$1k.

          If the cost of yard space is not an issue, simply install the high voltage fence a foot or so away from the steel chain link fence. The distance between the steel chain-link fence and the high voltage fence reduces the magnetic influence of the one on the other. The magnetic influence is proportional to the distance squared.