B Satellite link » History » Version 4
VEILLARD GAROZ, Loïc, 03/20/2015 10:01 PM
| 1 | 1 | VEILLARD GAROZ, Loïc | h1. B Satellite link |
|---|---|---|---|
| 2 | 1 | VEILLARD GAROZ, Loïc | |
| 3 | 1 | VEILLARD GAROZ, Loïc | h2. Pointing |
| 4 | 1 | VEILLARD GAROZ, Loïc | |
| 5 | 1 | VEILLARD GAROZ, Loïc | After some experiments, we have confirmed that the main factor of the SNR value is the correct pointing of the antenna as expected. Experimental uses have show that we may point the antenna to a little lower angle of elevation than expected (37-38 instead of 39-40 as asked by the satellite position estimation) This can be due to an error of the position calculation, some deviations on the structure of the antenna or improper antenna montage by the user. |
| 6 | 1 | VEILLARD GAROZ, Loïc | |
| 7 | 1 | VEILLARD GAROZ, Loïc | We advice to spend some time with the antenna pointing in order to get the higher SNR. The antenna sign of connection is not a consequence of the best link, is just a consequence of the possibility of setting up the link. That means that we don't have use to follow the signals from the Tria but add some time and effort to set a proper link. |
| 8 | 1 | VEILLARD GAROZ, Loïc | |
| 9 | 1 | VEILLARD GAROZ, Loïc | From our experiments we got values between 5 and 10.3 dB of SNR after the connection with low shifts of the elevation and the azimuth. |
| 10 | 1 | VEILLARD GAROZ, Loïc | |
| 11 | 1 | VEILLARD GAROZ, Loïc | h2. Clear sky |
| 12 | 1 | VEILLARD GAROZ, Loïc | |
| 13 | 1 | VEILLARD GAROZ, Loïc | Under clear sky we have obtained this characteristics: |
| 14 | 1 | VEILLARD GAROZ, Loïc | |
| 15 | 1 | VEILLARD GAROZ, Loïc | IMAGE |
| 16 | 1 | VEILLARD GAROZ, Loïc | |
| 17 | 1 | VEILLARD GAROZ, Loïc | And for transmission: |
| 18 | 1 | VEILLARD GAROZ, Loïc | |
| 19 | 1 | VEILLARD GAROZ, Loïc | IMAGE |
| 20 | 1 | VEILLARD GAROZ, Loïc | |
| 21 | 1 | VEILLARD GAROZ, Loïc | Which granted a BW in that case of: |
| 22 | 1 | VEILLARD GAROZ, Loïc | |
| 23 | 4 | VEILLARD GAROZ, Loïc | IMAGE |
| 24 | 4 | VEILLARD GAROZ, Loïc | |
| 25 | 1 | VEILLARD GAROZ, Loïc | h2. Low rain conditions |
| 26 | 1 | VEILLARD GAROZ, Loïc | |
| 27 | 1 | VEILLARD GAROZ, Loïc | In the other hand, under rain conditions we had the following results: |
| 28 | 1 | VEILLARD GAROZ, Loïc | |
| 29 | 1 | VEILLARD GAROZ, Loïc | !lowrain.png! |
| 30 | 1 | VEILLARD GAROZ, Loïc | |
| 31 | 4 | VEILLARD GAROZ, Loïc | We can compare it with some an almost clear sky conditions, with a 1.5dB improvement of the SNR |
| 32 | 3 | VEILLARD GAROZ, Loïc | |
| 33 | 3 | VEILLARD GAROZ, Loïc | !clouds.png! |
| 34 | 3 | VEILLARD GAROZ, Loïc | |
| 35 | 1 | VEILLARD GAROZ, Loïc | And for the transmission: |
| 36 | 2 | VEILLARD GAROZ, Loïc | |
| 37 | 1 | VEILLARD GAROZ, Loïc | !transmissionclouds.png! |
| 38 | 1 | VEILLARD GAROZ, Loïc | |
| 39 | 4 | VEILLARD GAROZ, Loïc | With the following available BW: |
| 40 | 1 | VEILLARD GAROZ, Loïc | |
| 41 | 2 | VEILLARD GAROZ, Loïc | !cloudsBW.png! |
| 42 | 1 | VEILLARD GAROZ, Loïc | |
| 43 | 1 | VEILLARD GAROZ, Loïc | h2. Conclusions |
| 44 | 1 | VEILLARD GAROZ, Loïc | |
| 45 | 1 | VEILLARD GAROZ, Loïc | We have to focus in the fact that the most important factor to have a good link is the pointing of the antenna. While the rain may attenuate the signal some dBs, we have seen that the satellite from our provider is probably running ACM, which definitively points out the pointing of the antenna as the main factor |