AmateuRadioMalaysia

Wednesday, January 04, 2006

Fancy making you own VHF Antenna?

VHF Direct Connect Beams

Here are some lengths and spacings for various direct connect beams. The layouts are straight forward and are illustrated below. Your SWR should be less than 1.3:1 with these designs.



The driven element is cut into two halves and insulated from the boom with nonmetalic material. Then the two wires of the coax are connected, one to each section of the driven element. You may drill small holes and use sheet metal screws to accomplish this.



The reflector, director 1, and director 2 can be attached directly to the boom by a variety of methods. There are some helpful hints for antenna construction on our antenna construction tips page.

EXAMPLE

2 Meter 4 element beam center frequency 146.52 MHz
using 1/2" diameter tubing


Reflector Element Length [38-1/8 "]

Driven Element [36 "]

Driven Element spacing from reflector [24-1/4 "]

Director 1 length [34-1/2 "]

Director 1 Element spacing from Reflector [49 "]

Director 2 length [34-3/8"]

Director 2 Element spacing from Reflector [71-1/2"]


Typical Gain 8.43 dbd F/B 13.32 db

For full details please goto: http://www.qsl.net/w4sat/antlegn.htm

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