Hi All, The radials need to remain at 1/4 wavelength long. The base of the antenna needs to have an inductor to make the radiating element 3/4 wave electrical, but 5/8 wave physical, thus matching to 50 ohms resistive. Element diameter needs to be considered in the wave length calculation. See ARRL Antenna Manual "K Factor" Art, KC6UQH

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Nigel Gunn G8IFF/W8IFF Sent: Saturday, March 14, 2009 8:07 PM To: VE6ITV Cc: Amsat Subject: [amsat-bb] Re: help on antenna project

Multiply all 1/4 wave dimensions by 2.5 but the impedance will change and you will then need a matching network.

VE6ITV wrote:

Hi, i have a little fm radio station and use a 1/4 wave with radials, i

would like to know the dimensions to make a 5/8 wave with radials, any help appreciated. VE6ITV Scott

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