Presented by Heart Of Texas Amateur Radio Club (HOTARC)

1. Technician License ClassGordon West Technician Class ManualPages 115-131Digital Signals & Space Communications Presented by Heart Of Texas Amateur Radio Club (HOTARC)

2. Internet and Amateur Radio • See pages 122 – 123… • Key words: • Internet • IRLP = Internet Radio Linking Project • Echolink voice over Internet • T6 A03: gateway to the Internet Weak Signals, Digital Communications

3. T6A03 (pg 122) • What name is given to an amateur radio station that is used to connect other amateur stations to the Internet? • A gateway • A repeater • A digipeater • A beacon station Weak Signals, Digital Communications

4. EchoLink Weak Signals, Digital Communications

5. T6B02 (pg 123) • What does the abbreviation IRLP mean? • Internet Radio Linking Project • Internet Relay Language Protocol • International Repeater Linking Project • International Radio Linking Project Weak Signals, Digital Communications

6. T6B05 (pg 123) • What method is used to transfer data by IRLP? • VHF Packet radio • PSK31 • Voice over Internet protocol • None of these answers are correct Weak Signals, Digital Communications

7. T6B11 (pg 123) • When using a portable transceiver how do you select a specific IRLP node? • Choose a specific CTCSS tone • Choose the correct DSC tone • Access the repeater autopatch • Use the keypad to transmit the IRLP node numbers Weak Signals, Digital Communications

8. T6B10 (pg 123) • Where might you find a list of active nodes using VoIP? • The FCC Rulebook • From your local emergency coordinator • A repeater directory or the Internet • The local repeater frequency coordinator Weak Signals, Digital Communications

9. T6B07 (pg 123) • Which one of the following allows computer-to-radio linking for voice transmission? • Grid modulation • EchoLink • AMTOR • Multiplex Weak Signals, Digital Communications

10. T6B03 (pg 124) • Who may operate on the Echolink system? • Only club stations • Any licensed amateur radio operator • Technician class licensed amateur radio operators only • Any person, licensed or not, who is registered with the Echolink system Weak Signals, Digital Communications

11. T6B01 (pg 124) • How is information transmitted between stations using Echolink? • APRS • PSK31 • Internet • Atmospheric ducting Weak Signals, Digital Communications

12. T6B08 (pg 124) • What are you listening to if you hear a brief tone and then a station from Russia calling CQ on a 2-meter repeater? • An ionospheric band opening on VHF • A prohibited transmission • An Internet linked DX station • None of these answers are correct Weak Signals, Digital Communications

13. Packet Radio • See pages 124 – 125… • Key words: • Packet • Terminal • Sound card (in your computer) • What is a packet system? Weak Signals, Digital Communications

14. A Packet System Key ideas: • Use radios to connect computers (digital communications), just as telephone lines were used in the past. • Instead of a modem, we use a device called a Terminal Node Controller, or TNC. • Since computers are doing the talking, there is no need for a microphone in a packet system. Weak Signals, Digital Communications

15. A Packet System (The Old Way) TELEPHONE MODEM MODEM TELEPHONE Weak Signals, Digital Communications

16. A Packet System (The New Way) RADIO TNC TNC RADIO Weak Signals, Digital Communications

17. T6 C01 (pg 124) • Which of the following is an example of a digital communications method? • Single sideband voice • Amateur television • FM voice • Packet radio One of many types of computer-to-computer radio communications Weak Signals, Digital Communications

18. T5 A08 (pg 125) What is connected between the transceiver and computer terminal in a packet radio station? • Transmatch • Mixer • Terminal Node Controller • Antenna Usually known as aTNC Weak Signals, Digital Communications

19. T5 A09 (pg 125) Which of these items is not required for a packet radio station? • Antenna • Transceiver • Power source • Microphone Weak Signals, Digital Communications

20. RADIO T5 A10 (pg 125) What can be used to connect a radio with a computer for data transmission? • Balun • Sound Card • Impedance matcher • Autopatch TNC Weak Signals, Digital Communications

21. T5 D13 (pg 126) • What is one of the reasons to use digital signals instead of analog signals to communicate with another station? • Digital systems are less expensive than analog systems • Many digital systems can automatically correct errors caused by noise and interference • Digital modulation circuits are much less complicated than any other types • All digital signals allow higher transmit power levels Weak Signals, Digital Communications

22. a “waterfall” display showing several PSK QSOs occurring PSK • See pages 126… • Key words: • Low-rate (i.e., slow) data • Phase Shift Keying • Two questions you might see… Weak Signals, Digital Communications

23. T6 C07 (pg 126) • What is PSK31? • A high-rate data transmission mode used to transmit files • A method of reducing noise interference to FM signals • A type of television signal • A low-rate data transmission mode that works well in noisy conditions Weak Signals, Digital Communications

24. T6 C06 (pg 126) • What does the abbreviation PSK mean? • Pulse Shift Keying • Phase Shift Keying • Packet Short Keying • Phased Slide Keying Weak Signals, Digital Communications

25. GPS and Amateur Radio • See pages 126 – 127… • Key words: • Position • Global positioning system (GPS) • Two questions you might see… Weak Signals, Digital Communications

26. T6 C02 (pg 126) • What does the term APRS mean? • Automatic Position Reporting System • Associated Public Radio Station • Auto Planning Radio Set-up • Advanced Polar Radio System Weak Signals, Digital Communications

27. T6 C03 (pg 127) • What item is required along with your normal radio for sending automatic location reports? • A connection to the vehicle speedometer • A connection to a WWV receiver • A connection to a broadcast FM sub-carrier receiver • A global positioning system receiver Weak Signals, Digital Communications

28. Satellites and Amateur Radio • See pages 127 – 131… • Key words: • AMSAT • Any amateur • Satellite sub-bands • You’ll get one of these questions… Weak Signals, Digital Communications

29. T7 B08 (pg 127) What is the name of the group that coordinates the building and/or launch of the largest number of amateur radio satellites? • NSA • USOC • AMSAT • FCC Note: This is one time where the “FCC” is notthe correct choice. “SAT”  satellite Weak Signals, Digital Communications

30. T7 B06 (pg 127) • What should you use to determine when you can access an amateur satellite? • A GPS receiver • A field strength meter • A telescope • A satellite tracking program • There are many free programs—just download them!! Weak Signals, Digital Communications

31. T7 B01 (pg 128) • What class of license is required to use amateur satellites?? • Only Extra class licensees can use amateur radio satellites • General or higher class licensees who have a satellite operator certification • Only persons who are AMSAT members and who have paid their dues • Any amateur whose license allows them to transmit on the satellite uplink frequency • We’ll see also T7B04 on pg 131—again, any amateur! Weak Signals, Digital Communications

32. T7 B02 (pg 128) • How much power should you use to transmit when using an amateur satellite? • The maximum power of your transmitter • Theminimum amount of power needed to complete the contact • No more than half the rating of your linear amplifier • Never more than 1 watt • For any contact, always use the minimum power necessary. Weak Signals, Digital Communications

33. T7 B09 (pg 130) • What is a satellite sub-band? • A special frequency for talking to submarines • A frequency range limited to Extra Class licensees • A portion of a band where satellite operations are permitted • An obsolete term that has no meaning • Since satellite signals are weak, we keep them in a separate portion of the band—easier to hear! Weak Signals, Digital Communications

34. T7 B10 (pg 130) • What is the satellite sub-band on 70-cm? • 420 to 450 MHz • 435 to 438 MHz • 440 to 450 MHz • 432 to 433 MHz • You just have to memorize this, but notice that: • 35 + 35 = 70 Weak Signals, Digital Communications

35. T7B05 (pg 127) • What is a satellite beacon? • The primary transmit antenna on the satellite • An indicator light that that shows where to point your antenna • A reflective surface on the satellite • A signal that contains information about a satellite Weak Signals, Digital Communications

36. T7B03 (pg 129) • What is something you can do when using an amateur radio satellite? • Listen to the Space Shuttle • Get global positioning information • Make autopatch calls • Talk to amateur radio operators in other countries Weak Signals, Digital Communications

37. T7B07 (pg 129) • What is Doppler shift? • A change in the satellite orbit • A mode where the satellite receives signals on one band and transmits on another • A change in signal frequency caused by motion through space • A special digital communications mode for some satellites Weak Signals, Digital Communications

38. Doppler Shift Doppler shift is a change in frequency as an object moves. The wave in front of the object is compressed, and expanded behind. To a fixed observer, the shortened wavelength in front causes the frequency to increase. As the object passes overhead, the longer wavelength behind will cause the frequency to decrease (lower value). The observer will need to adjust his radio accordingly during the pass. Weak Signals, Digital Communications

39. T7B11 (pg 129) • What do the initials LEO tell you about an amateur satellite? • The satellite battery is in Low Energy Operation mode • The satellite is performing a Lunar Ejection Orbit maneuver • The satellite is in a Low Earth Orbit • The satellite uses Light Emitting Optics Weak Signals, Digital Communications

40. T7B04 (pg 131) • Who may make contact with an astronaut on the International Space Station using amateur radio frequencies? • Only members of amateur radio clubs at NASA facilities • Any amateur with a Technician or higher class license • Only the astronaut's family members who are hams • You cannot talk to the ISS on amateur radio frequencies Weak Signals, Digital Communications