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Help With Yagi Antenna

I calculate the size of everything in online calculator.
sizes.
________________RE_________DE_____D1_____D2_____D3_____D4_____D5
Length(mm)______368_______357____340_____337____334____331_____328
Spacing(mm)______0________179____235_____370____531____717_____927
DE the bending length 579mm
SWR came more than 50 and it is bad.
Help me find the true size yagi antenna at 401.5 MHzAysen 16th Apr 2016
07:48
Hi Aysen

Several factors effect the SWR of antennas...

SWR should be measured at the feed point of the antenna, otherwise the following may happen.

Feed line is as important as the antenna itself.. make sure that you use proper impedance feed line and that it is of excellent quality, as UHF can have tremendous loss in signal. Also, N type or similar connectors should be used, as HF connectors have bad characteristics at UHF.

Metal and other conductive materials near the antenna can be detrimental to the antenna performance.

The material used for the antenna boom and elements are critical.. If you design a yagi for an insulated boom and use metal instead, then the antenna probably will not work.

And lastly, the method that is used to connect the feed line to the antenna must be electrically and mechanically secure.

You show the length of the elements, but not the spacing distance. Each element needs to be spaced correctly on the boom as calculated.

If you can tell us more about your particular antenna, maybe we can help.



Bobbie 20th Apr 2016
07:35
Hi Bobbie
I finished the Yagi antenna. I received an acceptable SWR and active resistance. it remains only to wait for receiver.
I can send the project for MMana Gal.

write me
aispop@yandex.ru Aysen 21st Apr 2016
04:40