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Chapter 8

Chapter 8. Other Communications Systems. Overview. Flags and Whistles Amateur Radio Cell Phones Family Radio Service General Mobile Radio Service Wi-Fi Loud Hailers Summary. >>. Flags and Whistles. International Flags and Pennants Nelson’s Message Common Nautical Signals

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Chapter 8

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  1. Chapter 8 Other Communications Systems

  2. Overview • Flags and Whistles • Amateur Radio • Cell Phones • Family Radio Service • General Mobile Radio Service • Wi-Fi • Loud Hailers • Summary >>

  3. Flags and Whistles • International Flags and Pennants • Nelson’s Message • Common Nautical Signals • Weather Warning Signals • Common Whistles – Maneuvering Signals >>

  4. Signal Flags • On Left • International Flags & Pennants • On Right • Special meaning of alphabet Flags >>

  5. Nelson’s Message >>

  6. Common Nautical Signals • Limited maneuverability due to diving • Rigid alpha flag • Diver in water • U.S. signal for scuba diving in progress • Request Pratique • Permission to enter and use foreign port • Quebec flag >>

  7. Quiz November Charlie What is the meaning of these two flags? Hint: same as this flag “Distress” - Both are from Nav Rule 37 >>

  8. Weather Warning Signals • National Weather Service Flags and Lights • Historical Signals • Replaced by Radio15 Feb 1989 >>

  9. Given using air horn or vessel’s horn US (inland) sound signals One or two short* Meeting, crossing or overtaking signals If in agreement, reply with like signal * May be given on radio Three short Operating astern propulsion Five short DANGER! One prolonged Leaving dock or berth Sound Signals >>

  10. Amateur Radio • Introduction • The amateur radio license • How to obtain an amateur radio license • Amateur radio nets • Using amateur radio to access email >>

  11. Good References >>

  12. Introduction • For communications with other amateurs • 170,000 in United States • Amateurs in other countries • Only restriction: no commercial business • American Radio Relay League • National association for amateur radio • www.arrl.org >>

  13. Frequencies • Amateur Frequencies (partial list) • MF, HF, VHF and higher • 80 meters 3.5 to 4.0 MHz • 40 meters 7 to 7.3 MHz • 20 meters 21 to 21.350 MHz • 10 meters 28 to 29.7 MHz • 2 meters 144 to 148 MHz >>

  14. US Amateur Radio Bands >>

  15. Amateur Radio Licenses • Technical License • Written test only • No Morse Code • since Jan 2007 • Three Classes • Technician • VHF and higher • General • most Ham frequencies • Extra Class • all Ham frequencies >>

  16. Amateur Radio Marine Nets • Maritime Mobile Service Net • 0100 to 0300 and 1700 to 2300 GMT (except Sunday) • 14.300 MHz (20 meters) • Phone patch and message relay • Waterway Radio and Cruising Net • Daily from 1245 to 1400 UTC • 7.268 MHz (40 meters) • Accepts position reports and provides weather info • USPS • Saturday from 1700 to 1800 UTC • 14.287 MHz (20 meters) • USPS activities, boating news and radio subjects • Pass position reports and short messages to family >>

  17. Cell Phones • United States Frequencies • 850 (824 to 894) MHz • 1900 (1850 to 1990) MHz Cell tower Antennas Cell Phone >>

  18. Cell Phone Technical - 1 • Cell phone (digital) modulation schemes • TDMA (Time Division Multiple Access) • Using GSM (Groupe Spécial Mobile) standard • CDMA (Code Division Multiple Access) • Today used by about half of cell phones • Future is 3G for all cell phones >>

  19. Cell Phone Technical - 2 • Cell phone concept • Small cells (hexagonal coverage areas) • fixed antennas at intersection of three cells • typical cell is approximately 3 miles wide • illustrated on next slide • Low power radios and reuse of frequencies • Inexpensive handsets • Elaborate computer controlled switching equipment >>

  20. Cell Layout • Typical cells are 10 square miles • Cell towers are located at the junction of 3 cells • Each cell is separately managed >>

  21. 4 or 8-foot 3dB gain 18-inch 9dB gain Extending Cell Phone Range • Low power system with land-based cells • Handset power is 0.6 watts (600 milliwatts) • Range is less than 10 miles • To increase range: • Move outside and higher • Consider outside gain antenna • Install a 3 watt amplifier >>

  22. Family Radio Service • Handheld ½ watt 460 MHz FM radio • On-water range of 2 to 4 miles • No FCC license is required • Nautical uses • Intra-vessel • Vessel to crew/passengers on shore • Personal and social conversations • Has no calling/emergency frequency >>

  23. FRS / GMRS / GPS FRS only FRS / GMRS FRS Radios • May be packaged with • Weather and/or GPS receiver • GMRS radio >>

  24. FRS Technical • 14 channels 462.5625 to 467.7125 MHz • FM modulation with 25 kHz channel spacing • Channels 1 to 7 are shared with GMRS • Channels 8 to 14 are FRS only • No external antennas or amplifiers permitted • Radios use “Coded Squelch” • Normally one of 38 sub audible tones • 67 to 250.3 Hz • Not always identical between manufactures • “Quiet” does not mean frequency is not in use >>

  25. General Mobile Radio Service 22 channels in the 460 MHz band Channels 1 to 7 are shared with FRS, may use 5 watts Channels 8 to 14 may use FRS frequencies at ½ watt Channels 15 to 22 are for GMRS only, may use 5 watts Like FRS, uses Coded Squelch FCC operators license is required One adult per immediate family Must have license to use FRS/GMRS radio Unless only used on FRS frequencies at FRS power GMRS >>

  26. Notebook Wi-Fi adapter card 32 milliwatts Horizontal Antenna Embedded PC Wi-Fi card 32 milliwatts Horizontal Antenna Access Point Vertical Antenna Wi-Fi • 802.11g protocol @ 2.4 GHz • Good out to about 150 yards, at reduced data rates >>

  27. Wi-Fi Technical • Internet access using 802.11 protocol • Max data rate 54 Megabits/sec (802.11g) • Throughput is typically less than half the data rate • Marina access point – vertical antenna • Identified by its SSID • Either open or closed system • Notebook network adapter – horizontal antenna • 32 milliwatts at 2.4 GHz • No license is required • If a closed system: • Requires an encryption key (from marina) to use • Probably a charge for use >>

  28. Wi-Fi Protocols • Current 802.11g protocol • 54 Mbps max to 100 feet • Down to 6 Mbps at 150 yards • Older 802.11b protocol • 11 Mbps max to 100 feet • Future draft 802.11n protocol • 248 Mbps maximum • Wi-Fi 2.4 GHz band is shared (interference) • Microwaves • Cordless phones >>

  29. External USB Port Wi-Fi Adapter 200 milliwatts Vertical Antenna Access Point Vertical Antenna Extended Range Wi-Fi • For 1,000 foot Wi-Fi range, you need: • Both antennas vertically polarized • More power at PC Wi-Fi adapter Outside Wi-Fi 6.4 dB 21” Vertical Antenna >>

  30. Loud Hailers • Types • Portable • Installed • Integrated • 25 to 30 watts • Requires 5A of DC >>

  31. Loud Hailers • Primary purpose • Voice communication over short distances • Amplify voice from helm • Secondary purpose • Provide fog signals • Listen-back • Speaker orientation • Long axis of speaker must be vertical >>

  32. Summary • Can’t use amateur radio on marine bands • Cell phones • For personal/private calls • VHF-FM is better for on-water emergencies • FRS is good for ship-to-shore and personal • GMRS requires a license • Wi-Fi • High-speed internet in marina • Loud Hailer • Speaker orientation is important >>

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