Now in its 32nd year, Information Station Specialists is the nation's best known source for information radio stations (TIS/HAR), advisory signs and the specialized services required to transmit spoken messages to citizens. ISS is the only such source providing products entirely made in America.
 
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TechTalk with Tom Coviak

Underground Power
Why a Groundplane is Important, How It Works & Is Installed

Assuring a Strong Signal
Every agency that has invested in a low power AM radio station wants a good, strong signal.  The strength of the signal is directly related to how well the station's groundplane is designed and installed.  

Physics and Construction
The vertical portion of the antenna and the horizontally oriented groundplane together are responsible for the creation of the station's signal.  The groundplane literally "completes the circuit," explaining why its presence is critical beneath the antenna.
     ISS' patented PowerPlane® Factory-Assembled Groundplane is composed of 62 copper ground radials (12-gauge) tied to an inner ring of (4-gauge) copper wire. Sixty-two radials extend outward from the inner ring in every direction, creating a circular pattern.  (See the below drawing.)   

Installation Tricks
When working with the upper end of the AM band, we recommend extending the 62 radial loops 10 feet.  For lower frequencies, cut the radial loops at the inner ring and extend them to 20 feet. 
    For a pole-mounted system, the ground surrounding the antenna pole should be excavated. Route the pigtail of #4 gauge wire from the inner ring of the groundplane
and up the pole to the groundlug in the lightning arrestor enclosure.
For assistance with your groundplane installation, contact ISS.

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© 1983-2014 Information Station Specialists, Inc • All Rights Reserved
PO Box 51, Zeeland, Michigan, USA, 49464-0051
Phone 616.772.2300, Fax 616.772.2966,
Email ISS

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Patents: PowerPlane "Flex" Factory-Assembled Groundplane (#5,495,261) & Vertical Profile Antenna System (#7,027,008).
Trademark: ALERT AM® Emergency Advisory Radio Station.

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