Is this focal theory right or not?

RimaNTSS said:
In fact, the right distance is very easy to adjust by the maximum signal from the satellite.
Click to expand...

Well yes, of course :Y ...... when the length of the arms allow the clamp to be positioned at the needed distance from the dish.

When you have the clamp fixed at 2 cm from the focal point, but the needed distance is 3.5 cm from the focal point, you'd have wished that you had made that distance a bit more flexible. That's why a range between 1 to 4 cm or so would be advisable (for @SEOShamsher ).

Greetz,
A33
 
RimaNTSS said:
Sure I have. There you go View attachment 168600

@RimaNTSS

just saw this online and I got this question. Your dish have focal set below dish center but below image saying use dish center. is it due to oval round shape of dish. Is your dish round or oval? Please shed some light here.​

Click to expand...

f75ca511-797d-450b-a3ff-2edd939b673f.webp
 
SEOShamsher said:

Is your dish round or oval?​

Click to expand...
Not only mine oval, yours as well. Prodelin 1.8m is an offset dish with offset angle 22.3* (working area vertically 1930mm, horizontally 1786mm). Proper way to point the feed is not to center, but below it. Install the dish and try different positions of the feed and find it's best position. :cool:
 
@SEOShamsher : I am an advocate for aiming at the deepest point of a dish, which is indeed below the center.
For this dish: deepest point is 1048 mm away from top of dish (and 912 mm from bottom of dish).

Others do aim at an even lower point ("G-spot") of an offset dish, which lies on the bisector line: bisecting the lines from focal point to top and bottom the dish.
That would give the least spillover loss, but it would also miss the higher signal density of the higher parts of the dish. So aiming at the deepest point would be a good compromise for that.

But you can try for yourself, as @RimaNTSS suggested: Aim at the G-spot on the picture by RimaNTSS, or at the deepest point that I calculated, or anywhere inbetween....

P.S. I am not an advocate for the method of satsig.net, from which you posted the picture. I'm an advocate of taking measures of the dish itself, and do sound parabolic calculations on those measures.

Greetz,
A33
 
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