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Old 08-07-2005, 8:04 PM
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kf4lne kf4lne is offline
Join Date: Jul 2005
Location: Bristol, VA
Posts: 440

Using LMR 400 still exibits the same need for feedline decoupling as does any other coax. The ground radials will cut down on interference picked up because of the coax becoming part of the antenna, the radials are basically a wall that keeps the vertical element from benig able to induce stray RF on teh shield of the coax. As for the 3.5 foot antennas for low band, I am familiar with those antennas, I have one for my 6 meter mobile install. In the base of the antenna there is a coil of wire that makes up for the difference, this coil of wire has to be made a certain way or it wont work right and the antenna will not function. Same way CB antennas work, they have a coil of wire to make them electrically 1/4 wave length long when they are actually much shorter.

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