What am I doing wrong?

[BlackHawk]

You could try this. For the next few days the arc of the sun is passing behind the arc of the satellites. Use this link
http://www.globaltt.com/index-en.html?http://www.globaltt.com/(j4k2yf45x0nt2w550bprfpbh)/Tools/ToolsSolarOutage.aspx
to find out when the sun is behind [b]your[b] due south satellite. Point your dish at the sun by looking along the lnb arm at the correct time. Go off and have a cuppa for about 15 minutes until the sun has cleared from behind the satellite. Set your receiver to an active transponder and slowly move your dish up/down until you receive a signal. then do your tweaking.
BH

[BGonaSTICK]

Yes, the solar method is a neat trick, but two words of warning.

Obviously you shouldn't look directly at the sun for a moment longer than you have to, and secondly, if you have your dish pointing at the sun, you can expect the parabolic nature of your dish to focus the power of the sun directly where the LNB sits - and it can get fairy hot. Never stick your eye at this point!

[Analoguesat]

Fairy hot???

:roflmao: :clap:

[BGonaSTICK]

It's not my fault. The spell-checker should know what I mean! >

[linsladeboy]

Thanks for your knowledgeable advice and never ending support everyone!!!
Although I am a tad disappointed I didn't get motor going I must admit I am quite content with Hotbird at present ,which was satellite I was desperate to get from day one for Italian channels and Art Sport(what a bummer footie is going at end of season )
I will definitely get motor going this spring/summer so I will keep you updated on this great forum! :clap:
I also hope to take a couple of photos of current set up this weekend for you to cast your critical eye over :

[BGonaSTICK]

You know, I think that's a good attitude. You need to get some enjoyment out of all this. Everyone takes things at a different pace, and we have all the time in the world.

Let us know when you're ready for round two, or whatever number you're up to

[BlackHawk]

??? Fairy hot???

I stuck a digital thermometer sensor to the front of the lnb today. Moved the dish to 13 east and took note of the temps before and after the sun pass and the max reached during the pass.
Average temp before and after the pass was 14 degrees celcius.
Maximum temp at height of the pass was 18.1 degrees celcius.
Weather, light cloud along the slant path, sun visible throughout.
Physical temperature rise at the focal point of the antenna bears no relationship to the increase in electrical noise temperature recorded at the focal point during a sun pass.
ISTR, way back in my past, increases of well over 1000 degrees Kelvin noise temperature being recorded during sun passes.
BH

[BGonaSTICK]

I guess it's not really the time of year to see how hot it will go, and I agree it's not really related to microwave signal collection - just an unwanted side effect.

I think that the (heat/light) reflective properties of the dish face will have the greatest effect on temperature at the focal point.

The guy in the US who lined his (large) dish face with fragments of broken mirror mangaged to boil a kettle hanging where the LNB should be

In fact the BBC's 'Rough Science' series recently did something similar, but without going to the complexity of a complete parabolic 'dish'.

http://www.creative-science.org.uk/parabola.html

Now, that did get fairly hot

[BlackHawk]

Comes down to how efficient a satellite dish is in reflecting the light and heat frequencies to the focal point in comparison with 10-13GHz microwave frequencies.
A mirror surface will be more efficient in reflecting heat and light to the focal point. Hence sat dishes are of a matt finish so as not to melt the front face of the lnb.
I remeber, back in the 1960's when a new skin was put on the large dish at Goonhilly, I think that it is now named Arthur. The skin, petallised, was of stainless steel and had to be sand blasted all over to give it a matt finish. That was to ensure that the suns rays did not melt the melinex window across the aperture of the feed.
BH