1 / 32

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

lulu
Download Presentation

Chapter 8

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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 >>

More Related