Sky dish mod

Hi,

I just managed to get hold of a pair of sky dishes, sans LNBs.

I had a a look at http://tokoroa.nzwireless.org/skydish.html and http://www.trevormarshall.com/biquad.htm.

I found it odd that the first mod has the biquad on the "wrong" side of the mount. I realise it is pointing towards the dish, but shouldn't the biquad be in the same place as the antena of the LNB?

Generally, what are people's experiences with using sky dishes? Is there a better way to illuminate them than a biquad?

Thanks for any ideas...

Cantenna's have been used go here:
http://www.wwc.edu/~frohro/Airport/Primest.../Primestar.html


Helicals have been used also go here: http://www3.sympatico.ca/b.zauhar/SatAnt/2400Dish.htm

I find cantennas do not illuminate the dish enough - they pick up all the signal you need, but must only illuminate the middle 30cm of the dish.

As for helicals, they are only good for connections to another circularly polarised link of the same rotation (CW or CCW).

Mind you, I have heard that a helical connecting to a horizontal or vertically polarised ap should only be about 3db lower signal than if the node was the same power circularly polarised - have not confirmed this though.

Best bet would be to go with the biquad, but be prepared to be let down.
I personally think a patch antenna with a 60 degree beam spread would be the best feed for the job - Not yet tested

Thanks for all the links.

I decided to build a biquad, like trevormarshall's one. I had to make a few fudges, as the sky dish mount is a lot smaller than the primestar one he used. Also, I'm using cheap as ethernet cable for the feed (but there's only 10cm of it )

So far seems to work ok, goes through the width of my house to a ~16db helical on the other side and gets 80% signal... will try out outdoors tomorrow...

BTW, soldering coax to a circuitboard is tricky (but possible).