Re: Reception of C band - Problem #aero

Paul Gulliver
 

Patrick,

My method is the following for elevation: I place my offset dish in vertical position, note the index on the dish indicator and rotate the dish by 10° according to the dish indicator. I hope it is a correct way to do for an offset dish (?).

I think this works with prime focus dishes but not off set dishes - I found this article which may help to explain - although I'm not suggesting your dish is off set by 22 deg - but this is just an example


As I mentioned before my dish appears to look down below the horizontal. Perhaps the idea for you would be to get the Azimuth correct, align the dish to look horizontally (dish edges vertical) and then lower the elevation in small amounts until a signal appears ( the frequencies I'm looking at are 1533.92 and 1534.46MHz - subject to variations in the LNB local oscillator)

Keep trying, I'm sure you will succeed in the end  :)

Paul



On 27/12/2018 at 11:06, Patrick Lindecker <f6cte@...> wrote:

Hello Paul,

 

>Just re-reading your original post, did you align your dish with your L band antenna, this is what I do, I fix my L band helix in place of the LNB and carry out basic alignment and then put the LNB back in >place. I usually have to tweak the alignment to maximise the C-band signal. I take my receiving laptop outside and have it next to my dish and watch the signal strength as I tweaking.

I will try to apply your method next time (fixing my poor helix antenna for L band).

 

>Regarding precision, yes with a 1.1m dish the signal is weak at best so you do have to be accurate, I find just 2 or 3 degrees off can make a big difference - I also notice on my off set dish, the indicator >scale on the dish has no relation to reality, it's showing around 30  deg elevation when it's actually pointing around 10 degrees - by looks alone the dish appears to be pointing into the ground but this is a >feature of being "off set".

My method is the following for elevation: I place my offset dish in vertical position, note the index on the dish indicator and rotate the dish by 10° according to the dish indicator. I hope it is a correct way to do for an offset dish (?).

With a gap of 5° compared to the ideal pointing (in azimuth and elevation), do you see at least a weak signal (from which you can refine the pointing) or no signal at all?

 

>Hope you have better luck today,

I must go into my sister garden as I have no direct vision of 3F5 (only 4AF4), so it is a bit complicated ☺.

 

73


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