Australian Ham Radio Discussion Forum ( AHRDF )

Hi all,
I have limited space (in the suburbs) and long yagi antenna are too long. (and narrow band).

I've been battling with a Short Backfire Antenna made out of a 2m satellite dish.

Pixture at www.unixservice.com.au/hamradio/antenna

It performs about 6db worse than the bi-quad pixtured also.

I have a much bigger piece of that fly-screen door ~40mm mesh, 1.5 x 1.2m.
I could put it on the satellite dish mount as a co-linear back screen.

Here is the problem:

It is big enough for three dipoles wide and four dipoles deep or down.
The feed for two dipoles wide and four down is easy.
But, how do you do three wide by four down?

Any thoughts?

A google search for "phased array" is all but useless.

Alan VK2ZIW

Hi Alan,

Think "3 half-waves in-phase (colinear)". Have a look here: http://www.creative-science.org.uk/3D_2m...inear.html

Then stack four of them.

2.2 cents.

(16-10-2017, 01:51 PM)VK2ZRH Wrote: [ -> ]2.2 cents.

Ah, GST ???

Yup ! It's damned well everywhere.

Hi Alan,
perhaps if you moved the feed out to the focal point of the 2 metre dish it would work. its way too close to the mesh at the moment.
The best way to set exact focus is to peak it on the noise from the sun. Measure sun noise rise using Owen Duffy's NFM program on your laptop plugged into the acc socket on the back of the radio, or an ac millivolt meter across the speaker etc.
73 Dave