This antenna was built the same way as the 437 Mhz crossed yagi, antenna details:-

Element Length

Ref 1007mm
DE 988mm
D1 920mm
D2 912mm
D3 903mm

Cumulative Boom Spacing

Ref 0
DE 411mm
D1 565mm
D2 935mm
D3 1377mm

I only made this antenna 5 element in order to be approx the same length as the 437 Mhz antenna. Besides this one is for the downlink. I also used the power divider/splitter for the phasing. Once again, the vertical section was placed ¼ wavelength in front of the other and I left approx 40mm over on each end of the boom.

Power divider/splitter:-

 

In the first drawing I have tried to show the copper water pipe in the centre of the box section.

The final SWR on the divider was adjusted by inserting a length of modeling plastic inside the airspace. The SWR went from 1.35 : 1 to 1.12 :1. The final combined SWR after tuning each gamma separately came to 1.06 : 1. Very happy here (in fact very surprised).

The final assembly:-

 

Nick Soter
Call: VK4ZXX
Location: Brisbane

VK4ZXX Ham Radio 145 Meg yagi Build

 

 

 

 

 

 

 

 

 

 

 

Web Links

 

 

 

 

 

 

 

 

 

Project Links

Project Comments

Rate this Antenna
@ dxzone.com

 

 

 

 

 

© vk4zxx 2013