Recommended Dish installation procedure (from Tek2000)

Discussions specifically related to master c band satellite television.
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Re: Recommended Dish installation procedure (from Tek2000)

Post by tvroadmin » Fri Oct 02, 2020 4:47 am

eelstrebor wrote:
Thu Sep 17, 2020 12:14 pm
Part of my problem with assembling on the ground is that I don't have any flat and level surfaces. I tried to fabricate something for a flat and level surface but that did not go as well as I had hoped.

No point in doing this. This method was being proposed at another forum but doesn't yield better assembly results. Let's investigate a bit and see why.

The wavelength of the signals used in C band communication satellites are about the diameter of your feed horn or say about 3 inches. It is the speed of light 300,000,000 m/s divided by the frequency, say 4.0 GHz. The satellite emits plane waves with a Cosine profile. Now to make sure the waves arrive mostly in phase, you should aim for a precision of 1/10th the wavelength or better. Do you understand why?

If two Cosine waves with the same phase are added together we get another Cosine with amplitude:

Cosine (0) + Cosine (0) = 2*Cosine (0) = 2*1 = 2 , so the amplitude is doubled and our signal is twice as strong.

Okay, now consider two waves with a phase difference of 1/10 the wavelength:

Cosine (0) + Cosine (360/10) = 1 + 0.81 = 1.81 , so our signal is not as strong as before, but pretty close to the theoretical limit.

So what is 1/10th the C band wavelength? It is about 0.3 inches. Get your tape measures out when assembling the dish panels. Even if you wear bottles for glasses :lol: , there is no way you are going to have a gap of more than 0.3 inches at the joint between two adjacent panels. It is real easy to check the surface accuracy of the dish when assembling it on the mount by just using your hands to feel the joint between two panels. I'd say you can probably get the surface error over the joint down to less than 0.1 inches just by feeling it. If you want better than that, maybe get your inclinometer out and take measurements across the panel joints. However, I don't recommend bother doing this, because the surface accuracy of the individual panels is probably no better than 0.1 inches in the first place. Remember, the panels are made in a mold, and extremely precise molds require a lot of $$$$$$$$. And in this case, as we have seen with our simple example, it doesn't help us much. If on the other hand, you assembled the dish on a flat surface, besides not being entirely certain it is perfectly flat, you can't even see or feel the surface of the reflector until you flip it over and at that point it's back to using your hands to feel how smooth the joints between the panels are. Even at ku wavelengths, 0.1 inches of surface accuracy will give excellent signal gain. It is only at ka wavelengths where efficiency starts to drop a bit.


If anyone is still stressing over this, even after we explained why you shouldn't, imagine the stress levels of the guy in the photo below. He was paid to fabricate the mirror used in the 2.4m Hubble Telescope. Instead of assembling panels, he had to polish the surface of the mirror and meet Nasa's specifications of 1/65th the wavelength of light or about 10 nanometers or about the size of the transistors in your modern electronic devices. The exact same principles apply, but he screwed up and Hubble was born myopic. :boo! I wonder if he checked to make sure his floor was level before polishing or if he just got bad advice from somewhere like our tvrosat members were getting. The optics was finally corrected and you can see the improvement in the picture below.

hubble_mirror.jpg

hubble_image.jpg


On the topic of Hubble, NASA certainly didn't aim very large. Why only 2.4m? You hardly resolve anything through interstellar space with that cookie cutter. Already in the 1930s, guys like Hermann Oberth and Wernher Von Braun were contemplating building 1000 m diameter space telescopes. With such a large space telescope or an array of them, you could easily resolve a planet the size of Earth many light years away. With an array of 10 such telescopes, you could see something the size of the United States all the way from Alpha Centauri!

For those who are interested, the angular resolution of a dish or telescope is roughly

Angular Resolution (degrees) = 7.7 * wavelength/diameter

So for a 3.0m diameter dish and 4.0 GHz signal, the angular resolution is about 0.2 degrees, which means your C band dish can just barely make out 2 satellite carrier signals if they were separated by only 0.2 degrees. In reality, we need to extract the useful information from the satellite carrier signal, so the operators space them out by at least 1-2 degrees. Perhaps now you can understand why a 1.2m diameter dish has a hard time decoding C band signals, besides being too small to allow for sufficient gain. The signals of adjacent satellites are also "blurred" together, which makes it harder to decode. The same formula above can give us the angular resolution of a 1000 m optical space telescope, which works out to 30,000 km near Alpha Centauri. This means objects just a bit larger than the Earth start to come into focus. If one were to use an array of such telescopes, perhaps the geographic terrain of such an interstellar planet could be mapped or even intelligent life detected! It's not like I am making any of this stuff up, just simple reason and people nearly a century ago were already thinking about these things.

https://www.nextbigfuture.com/2018/10/s ... copes.html

Just imagine how much more knowledge we would have about the Universe with such a practical project if NASA wasn't run by a bunch of Marxist idiots :retarded , who are obsessed with landing a woman on the moon and a queer on Mars by 2024. :lame:

This topic was originally posted because someone at another forum was worried about their C band dish assembly. With a little logic and reason, we concluded there is no reason to worry, unless you are fabricating a 1000 m optical space telescope to spy on a neighboring extra terrestrial civilization. :wink:
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Re: Recommended Dish installation procedure (from Tek2000)

Post by tvroadmin » Fri Oct 02, 2020 5:11 am

Hint hint, wink wink. Based on the what we learned above from the guy at the other forum who was worried about his dish panels fitting together, how large of an objective lens would Elon Musk's network of 50,000 Starlink cube sats need to snap your mug shot here on Earth multiple times a day and store it in a massive database at NSA/CIA headquarters? Assume the satellite's altitude is a few hundred miles and the resolution required is less than a meter?

Would the Globalists ever get up to such diabolical scheming? Food for thought... :scratchingmyhead: :eek:
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Re: Recommended Dish installation procedure (from Tek2000)

Post by fatso » Wed Oct 07, 2020 10:08 pm

tvroadmin wrote:
Fri Oct 02, 2020 5:11 am
Would the Globalists ever get up to such diabolical scheming? Food for thought... :scratchingmyhead: :eek:
That dirt bag Bill Gates is definitely involved. I found this story interesting

Eye in the Sky: Bill Gates Backs Real Time Global Satellite Surveillance Network


Won't be taking his covid vaccine either. :tongue
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Re: Recommended Dish installation procedure (from Tek2000)

Post by eelstrebor » Thu Oct 08, 2020 11:26 am

fatso wrote:
Wed Oct 07, 2020 10:08 pm
tvroadmin wrote:
Fri Oct 02, 2020 5:11 am
Would the Globalists ever get up to such diabolical scheming? Food for thought... :scratchingmyhead: :eek:
That dirt bag Bill Gates is definitely involved. I found this story interesting
I like the technology but someone always weaponizes it or use it for invasion of privacy or for some other nefarious use. But we do need to keep an eye on the real bad guys. I don't know if Gates (and others) is supporting this project for the money or for spying on people or both. I'm sure that governments will find it useful. :eek:

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Re: Recommended Dish installation procedure (from Tek2000)

Post by eelstrebor » Sat Nov 07, 2020 7:57 pm

Is this right? Doesn't seem to fit properly. The installation instructions shows the frame and I expanded the image and it looks like the declination brackets are installed correctly.
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Re: Recommended Dish installation procedure (from Tek2000)

Post by fatso » Sat Nov 07, 2020 8:15 pm

Hello. I have the same dish from tek2000. You got the L bracket on the arm backwards in your first picture. Rotate it by 180 degrees and you will be good. :okay

The bottom of your mount is hanging.. :sayno it needs to be bolted and wrenched down. :thumbsup
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Re: Recommended Dish installation procedure (from Tek2000)

Post by fatso » Sat Nov 07, 2020 8:26 pm

The next step is to set your elevation and declination angles correctly and point due south. I used this chart and was tracking the arc immediately.

https://www.tvrosat.com/resources.html
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Re: Recommended Dish installation procedure (from Tek2000)

Post by eelstrebor » Sun Nov 08, 2020 1:10 pm

fatso wrote:
Sat Nov 07, 2020 8:15 pm
Hello. I have the same dish from tek2000. You got the L bracket on the arm backwards in your first picture. Rotate it by 180 degrees and you will be good. :okay
The L bracket on the left (mount) or the one on the right (ring)?
fatso wrote:
Sat Nov 07, 2020 8:15 pm
The bottom of your mount is hanging.. :sayno it needs to be bolted and wrenched down. :thumbsup
I didn't bolt it down because there's a one-inch gap.

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Re: Recommended Dish installation procedure (from Tek2000)

Post by fatso » Sun Nov 08, 2020 7:04 pm

The L bracket on the left (mount).

As for the 1 inch gap, it looks like the ring is drooping down because you haven't wrenched down the declination bolts.
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Re: Recommended Dish installation procedure (from Tek2000)

Post by eelstrebor » Fri Nov 13, 2020 1:58 pm

Does this look correct?
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