Cassegrain offset dish antenna : where is the beam ?

[jujun]

Hello,

I just got for free a cassegrain offset dish antenna. So I am mounting it on my antenna rotator.
But I am facing a problem, it's not obvious at all to understand where the beam is in the vertical axis.

A picture of the different beam possibility, witch one is the good one ?

I must say that mechanicaly it would be easier if it was the blue or the yellow.

Also If you have any advice on this thing, I would love to hear them. (I'am thinking to add a focus motor)

Thank you

[VK5RC]

When I was mucking about with a 10GHz using an off centre fed dish (satellite dish) I used a weak signal source at about 30m away and found it experimentally - rather interestingly I also had a bit of a sideways squint as well !!!

[jujun]

I will build a massive attenuator, and try. Thank you