最新公安派出所民警工作手冊(cè)

1、1,C-C RIDER – A new concept for amateur satellites,Tom Clark, W3IWIW3IWI@amsat.org______________________________________________________________2003 AMSAT Annual Meeting Toronto – October, 2003,2,Future Amateur Sate

2、llites = Microwaves,Need More Bandwidth for Modern TechniquesL-Band (1260 – 1270 MHz) is Uplink OnlyS-Band (2400 – 2450 MHz) is a SEWER !WiFi LANBluetoothCordless TelephonesIn-home TV LinksMicrowave OvensThe “sew

3、er” has seriously compromised the performance of AO-40.,3,THE SEWER (and BPL Too) !!,4,,,United States Microwave Allocations,? means Earth-to-Space (uplink) direction only (Thanks to W4RI fo

4、r table)? means Space-to-Earth (downlink)direction only,,5,An Expanded Look at the C-Band(5.6 – 5.9 GHz) Microwave Picture,,P3E,6,C-C Rider – The Basic Concept,Single-band, In-band TransponderUplink: 5650-5670 MHzD

5、ownlink: 5830-5850 MHz Wide Bandwidth AvailableUp to 20 MHzUplink & Downlink Share One Antenna,About the C-C Rider name:,C-Band to C-band package to RIDE on future satellitesA famous Blues song written by Ma Rain

6、ey in the 1920’s,7,Why C-Band?,If we don’t use it, we will lose it !!!This region of the spectrum is under INTENSE scrutiny by the commercial world.It is the lowest frequency band that can support wide bandwidth links.

7、Digital Voice, Video, Multimedia, ???The paired Uplink and Downlink frequencies are a truly unique resource.Amateurs need the challenge to develop new technology and not grow stagnant.

8、 etcetera,8,But I have NO suitable C-band equipment now!,Nobody does!We will need to develop the ground-based user hardware IN PARALLEL with the spacecraft hardware.Leverage common technologyMost

9、of the microwave components unique to our C-Band needs could be stamped out “Cookie Cutter” for both spacecraft and ground use !!!,9,Some thoughts on progress…..,Amateur Radio needs new horizonsWhat will your shack look

10、 like in 5-10 years?Some words from the past:1975: Stick with Mode-A --- Mode-B is too advanced for amateurs.1980: Don’t publish satellite tracking software – amateurs will NEVER have computers in their shacks1986:

11、Digital satellites are of no interest to amateurs – stick with analog.1988: DSP – who needs it? Real men rely on LC and Xtal filters.1998: Nobody will ever use the Model L/S hardware on P3D. Give us Mode-B.1999: Only

12、a few people will be able to copy the P3D PSK telemetry.2001: Coding and FEC are too complicated to be used in satellite telemetry.etcetera,10,C-C Rider – The Basic Concept,,11,A simple user terminal might look lik

13、e:,,Note that all the microwave widgets are the same as those used on the spacecraft, except that TX/RX ports are reversed.,12,Instead of using a dish, how about using a Phased Array of Patch Antennas:,,Pointing data fro

14、m the multi-channel receiver is used to point the transmitter.,,½ watt C-band Ampscost about $10 from Hittite,13,To accommodate many types of users, the spacecraft might look something like:,,This might be a Phase

15、d Array,,14,And a Multi-Mode Ground User terminal might look something like:,,,,This might be a Phased Array,15,INMARSAT:A possible model for a C-C Rider user terminal?Commercial Price is under $5000Usable on Fiel

16、d Day & from apartment balconies.,,,16,Link Budget Estimates:C-C Rider on a LEO Platform,800 km orbit means path loss (both ways) ~175 dBSatellite: assume 2W TX with 6 dBiC antenna on a “bent-pipe” transponder Gro

17、und User: assume 30 cm dish or 3x3 array of patches and 70ºK LNALink supports 64kb/s digital or 64 kHz analog, and proper application of coding could bring this up to ~100 kb/s.

18、 ----------------------------------------------------------------BUT: The user antenna has beamwidth ~12º which needs to be pointed to 2-3º. Satellite peak motion is ~½º/s. T

19、he antenna pointing makes this a bad choice.However, the Doppler would only be like a satellite operating @ 180 MHz !!,17,Link Budget Estimates:C-C Rider on a GEO/GTO Platform,Assume satellite is at 36,000 km meaning

20、 path loss is ~200 dB.This means we need to pick up 25 dB over LEO!Spacecraft: 20 cm (3½?) aperture or patch array gives 17º beam with ~22 dBiC gain.Spacecraft TX: ~5 W (or ½ W per patch)Ground: 30 cm

21、 dish, 70ºK LNA & 10W TX ---------------------------------------------120 kb/sec bent-pipe or ~600 kb/s with FEC & Coding & demod/