Radial Length NMO Base Kit

davee223

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Dec 13, 2013
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New Jersey
Does anyone know the proper formula for the length of the ground plane radials for a 5/8 wave 450-470 mobile antenna. I purchased the kit and only have the formula for a 1/4 wave antenna. The antenna is only being used for receiving.

Thanks
 

N5XPM

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Jul 29, 2011
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Location
Texas
Does anyone know the proper formula for the length of the ground plane radials for a 5/8 wave 450-470 mobile antenna. I purchased the kit and only have the formula for a 1/4 wave antenna. The antenna is only being used for receiving.

Thanks
For receiving only, you will not notice a difference and should be fine regardless of radial length.
 

RadShackFan

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Jun 2, 2010
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Scroll down and you will find the formula calculator.
 

n0nhp

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Grand Junction
As long as the ground plane is 1/4 wave length or longer, it doesn't matter, transmit or receive
 

mmckenna

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Yeah, for the ground plane, Minimum of 1/4 wave is all you need. In other words, you do not need to have 5/8 wave ground radials for a 5/8 wave antenna.
 

N5XPM

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Jul 29, 2011
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158
Location
Texas
Yeah, for the ground plane, Minimum of 1/4 wave is all you need. In other words, you do not need to have 5/8 wave ground radials for a 5/8 wave antenna.

For commercially available "kits" they offer the kit by frequency band. The VHF kit will work for UHF, as the 1/4 wave VHF kit is longer than the 1/4 wave required for UHF frequencies. Since there are several radials, you are effectively creating a 1/2 wave ground plane. For transmitting, the UHF kit won't work well for VHF, since the radials are about 6" versus the 18" needed for the VHF frequency bands. For a base scanner antenna, the VHF base kit with a Tri-band mobile NMO mobile antenna is affordable and durable.
 
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