Satellite Communications

Transcription

1 Satellite Communications Presentation by Ron Herring W7HD Satellite Presentation v4 1

2 Communication factors 2

3 Communication factors part 2 3

4 Factors in Communication part 3 4

5 How distance affects loss 5

6 What the atmosphere does to satellite communication 6

7 Frequency bands 7

8 Frequencies hams frequently use for satellite communications VHF 2-meters HF 10-meters UHF 440MHz 2400 MHz S-band VHF and UHF are most common by far 8

9 Easy Sats 9

10 Easy Sat frequencies 10

11 First contact 11

12 Your First Contact 12

13 ISS contacts 13

14 Some of the tracking programs The Ham Radio Deluxe Satellite (HRD) program for Windows is very useful if you have a supported transceiver and/or computer-controlled az-el rotator. It can automatically adjust your radio for doppler shift. You may need to load an older version if the latest free version suddenly breaks due to a Windows update. Gpredict for Linux is very good. It is similar to Orbitron for Windows. 14

15 15

16 16

17 Which were heard and when 17

18 18

19 19

20 What Does It Take At minimum a dual-band VHF/UHF transceiver, a handheld is fine. Be aware that these can get HOT during extended operation. A small antenna some satellites can be worked with the rubber duck that comes with most handhelds. 20

21 The best gear to use A radio designed for satellite communications, such as the Kenwood TS2000. Software designed for satellite communications, such as the satellite module in Ham Radio Deluxe, which controls the radio AND a compatible antenna rotor. 21

22 What does the software do? Automatically adjust the frequency for the Doppler effect (think train whistle going by) Automatically position the antenna IF you have a compatible rotor controller. These are VERY expensive (we're talking $1500 for the rotor and controller). Maintain the latest TLE (two-line element) data from NORAD 22

23 Where do I get software and data The TLE data, also known as Keplerian data, can be downloaded from The Heavens-Above site at Munich Germany provides predictions for bright satellites, including Mir, ISS and the shuttle, plus Iridium satellite flares. The user may either select a nearby town or city or input their own coordinates. You can also set the time zone for accurate times. 23

24 What can go wrong? The biggest problem I have run into is that the satellite prediction programs don't seem to agree on exactly WHEN the satellite will be in view. Use UTC only, since time zones can change with daylight savings. Heavens Above, Gpredict and Orbitron seem to be the most accurate tracking programs. You also have to make sure that the program you are using is compatible with your operating system. Windows keeps changing, so your program may no longer work after an update. Linux Gpredict is the safest and most stable alternative. If there is thunder or lightning present, don't go out there. 24

25 Gpredict under Linux Installing Gpredict allows you to have a realtime view of satellite positions. It can automatically update the TLE files. Double-clicking on the satellite track brings up the Satellite Info window, where you can select Transponders to get frequency information. 25

26 Gpredict transponders 26

27 What if transponders has no info? You can add information to the transponders. Goto /usr/share/gpredict/data/trsp Add a file named as the satellite catalog number and add the information. See example on next slide. At minimum you would enter the [Mode V/U FM] data for an FM satellite. 27

28 Sample trsp data 28

29 Ham Radio Deluxe Satellite Screen 29

30 Selecting a satellite in HRD 30

31 Directly supported radios 31

32 Read the notes They are VERY important 32

33 Orbitron Main Screen 33

34 Orbitron Prediction 34

35 Serious satellite antenna system 35

36 But wait, there's more Places to find out more information:

37 Youtube videos on satellite tracking AE6LX Tim Tucker HO68 SO50 with UV5R Arrow Ant K7AGE AO51 K7AGE HRD Satellite Tracking KK4MND UV5R SO

38 The End Go to And click on the Ovarc Satellite Presentation link to get a copy of the presentation. 38