1. Balloon Communications Kevin Shoemaker Shoemaker Labs, Inc. Shoemakerlabs@gmail.com LCANS09

2. Communication Options VHF/UHF Line of Sight Shortwave – Digital Modes Meteor Scatter Satellite – Orbcomm, Inmarsat, Hamsat, GEO APRS Store and Forward

3. Radio Horizon

4. Path Loss PathLossdB=C20 ∗ logF ∗ R −G1−G2 where, F = Frequency in MHz R = Range in units defined by C G1 = Gain in dB of antenna 1 G2 = Gain in dB of antenna 2 C = 32.45 for Kilometers 37.80 for Nautical Miles 36.58 for Statute Miles -27.55 for Meters -37.87 for Feet

5. Bandwidth Requirements Noise Energy= kTB Telemetry – (Khz) Video – (MHz) Compression helps Conversion Gain

6. Short Wave Propagation Diurnal Changes Frequency Selection Important Digital Modes mitigate fading Worldwide coverage

7. Meteor Scatter 30 to 50 MHz operation Best 4-9 A.M. Low Power.5 Second windows max Medium Data Rate Packets

8. Inmarsat +82 to -82 Degrees Latitude Coverage L Band 2.4 to 64 KBit Data Rates

9. Inmarsat Equipment L Band Operation +82 to -82 Global Coverage Voice and Data Reasonably Priced

10. Iridium 66 LEO Satellites Significant Military Usage Initially financed by Motorola TCP/IP Supported

11. Iridium Equipment L Band operation (1610-1626 MHz, 1530-1559 MHz) Global Coverage Voice and Data Internet and e-mail capable

12. Automatic Packet Reporting System Global Coverage Low Data Rates Low Cost ISS Installation Multiple AMSAT Operation

13. APRS Balloons APRS Balloons

14. APRS 3D views for Balloon tracking

15. APRS in Space 2001 PCSAT-1 Prototype Comms. 2001 PCSAT-1 Prototype Comms. 2006 PCSAT2 on ISS 2006 PCSAT2 on ISS 2007 ANDE 2007 ANDE 2008 RAFT 2008 RAFT APRS space frequency is published as 145.825 APRS space frequency is published as 145.825 See live downlink on http://pcsat.aprs.org

16. Antenna Requirements VHF/UHF/Orbcomm – Monopoles, Omni patterns Inmarsat – Azimuth Tracking Iridium - Omni GEO – Alt/Az Tracking APRS – Omni Shortwave - Omni

17. Cost vs. Bandwidth Generally speaking, the higher the bandwidth, the higher the cost and complexity. Video rates generally require motion control for long distances Lower data rates simpler and lend themselves to efficient coding schemes, cheaper as a result Lower data rates propagate further