Thursday, November 3, 2011

70cm (440mhz) Yagi up and installed

Well I finally took the plunge and got my two sons up on the roof today and we installed my new beam antenna for 70cm or the MHz band. The antenna is a 20 element 18 directors one driven dipole and a reflector. It has a total length of 3.64 meters.

Unlike a television antenna I have mounted this one vertically with the elements running up and down as I am using it on FM in to repeaters with vertical antennas. I had to make up my own gamma match and used a 4:1 match for it made from coax.

The lowest antenna just above the roof line in the pic  is a UHF antenna for our country TV, the middle one is a VHF antenna for Melbourne TV and the top most is my Yagi on a rotator, the rotator is the bulge in the pole just below it. With this set-up I can hit the repeater at Arthur's seat 83 km away on 1 watt and the Cranbourne repeater 50 km away on 300 milli watts but with a lot of noise so I use 1 watt as well, this is better then before I had to use 5 watts in to my vertical for Cranbourne and couldn't hit Arthur's seat at 5 watts on the vertical at all.