ANTENTOP- 01- 2008, # 010

Simple Weekend Antenna for 145-MHz

Design of the antenna is very simple. Personally I have made the antenna in 40 minutes. Antenna consists from reflector (length 1002-millimeters) and vibrator (length 972- millimeters, gap for coaxial cable- 10-millimeters). Distance between reflector and vibrator is approximately 204- 210- millimeters. Antennas parts are made from insulated wire in diameter 4 millimeters. Place of vibrator, where a coax was installed, was protected with a raw compound.

You may use another protector... SWR for the antenna (measured by SWR-121) was (1.0-1.1):1.

Input resistance of the antenna is 12,5 Ohm, for matching with 50-Ohm Coaxial I have used a transformer made with two bridged length of 50-Ohms coaxial cable. The coax must have the similar length near 370- 440- millimeters (should be find at adjusting). Both pieces must be tied at all length one to another.

Another Big Gun

I was asked how is it possible to improve gain but save wide DD? To do this it is impossible to add another director, but it is possible to use two phase antennas. Picture below shows this way. Good chose to phase 2 or 4 antennas. We get good DD, good gain and the system can receive mobile stations in very good way compare to collinear antennas in 5- 7 meter long.

Credit Line:

http://www.hamradio.cmw.ru/antenna/145-2el.htm

http://www.antentop.org/

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