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Technical Tips from Mark W. Persons
Radial Chaser Updated

This is a Nott Ltd. Radial Chaser, used for locating ground radials around AM towers.  It is almost like hunting for buried treasure.  The unit detects RF current traveling in ground radials and drives a meter.  Operators can see whenever they are over radial wires, which are typically buried three to six inches.  They are typically #10 soft-drawn bare copper wires.  No need to dig up the wires.  Just run the meter over the ground. 

The Radial Chaser is often used to determine if ground radials are still present after many years in the ground.  FCC specifications call for 120 radial wires, going out like spokes of a wheel extending 1/4 wavelength in every direction like spokes of a wheel.   In the case of 540 KHz, those wires should be about 450 feet.  At 1000 KHz, they should be about 246 feet, and at 1600 KHz, they should be about 154 feet in length each.  The station license should tell the story.  Newer licenses do not show that so best to find an older license. 

The AM tower needs good working ground radials in order to function properly.  The ground radials are the other half of the antenna system.  Broken, cut, or missing radials will reduce antenna efficiency and coverage especially in the direction of the ground wire deficiency. 

The Radial Chaser has a ferrite bar antenna with variable capacitor to resonate it on any AM broadcast frequency, as seen on the photo at the left.  This modification shows an amplifier card to boost the received signal from the ferrite to a level 10 times higher.  This greatly improves sensitivity and usability.  A battery and battery test button are added to insure everything is working properly.

Used, but in good working order $350 plus shipping    

The stories go on and on.  Stop in again sometime.  I'll leave the soldering iron on for you. 
Mark W. Persons   ham W0MH      

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