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Radio Broadcast Technical Consulting and Sales
10032 Island Drive, Brainerd, MN  56401
Phone: 218.829.1326

AM Antenna Current Calibrator
For Remote Control Systems

Built by M. W. Persons and Associates, Inc.
Made in Minnesota

October 27, 2014:  It is amazing how customers come up with ideas for custom panels to solve needs that manufacturers ignore.  This one is is for AM antenna current calibration.  It goes between a current sample, such as a Delta TCA ammeter, and a remote control system.  The goal is to get exact calibrations of antenna current from five power levels on a single channel of the remote control.  Linearity of the sample is the problem.  Calibrating at high power and then changing to low power could give a sample that is way off and unusable for accurate determination of power.   A jeweler's screwdriver is used to set each sample level.  A rolled steel 19 inch wide rack panel has excellent rigidity for the task.
The panel has a DC amplifier on the left that boosts the incoming DC sample by a factor of five.  So, a 0.5 volt sample becomes 2.5 VDC.  Five relays, on the right, select which of the five 10-turn calibration controls is in use at the time.  This panel was constructed to automatically use "status" indications on a Broadcast Electronics 5000 watt transmitter to select the appropriate calibration control in five steps from 5000 watts down to as little as 25 watts..  
Close attention to detail is important. 

Wiring is run in such a way as to be easily serviceable or changed in the future.

Custom panels like this are built here often.

Questions?  Email Mark Persons:  teki@mwpersons.com       

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page last edited 02/22/2016