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Technical Tips from Mark W. Persons
RF Radiation Measuring

    RF Radiation can be a hazard around radio stations.  OSHA rules specify maximum allowed radiation limits for people in high RF fields.

We carry a Narda Broadband Isotropic Radiation Monitor, which is good from 0.3 MHz to 1.5 GHz.  The measurements are performed to judge compliance with Sections 1.1306 and 1.1307 of the FCC rules using OST Bulletin No. 65

We do the measurements when calculations show there could be a problem.  FCC rules require the measurements if the fencing around a "hot" tower is closer than the standard distance.  That distance is 10 feet for 1 KW and 17 feet for 5 KW of radiated power.         

    The meter clearly shows when and where the limit is exceeded.  
    In a difficult situation where a transmitter building is directly adjacent to a 5 KW AM tower, we used a grounded screen to bring RF radiation into limits. 
    Here is a closer look at the screen.  It is 1/4-inch "hardware cloth" available a hardware stores.  It is easy to install, usually with two people. 

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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