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Long Range Communications

Long Range Communications. Satellite Phones and Radios. MF/HF SSB Radio. >>. MF/HF SSB Radio. >>. MF/HF Overview. Basic Transmitter and Receiver AM Transmitter and Receiver SSB Transmitter and Receiver MF/HF Antennas MF/HF Licensing MF/HF Operations Summary. >>. Basic Transmitter

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Long Range Communications

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  1. Long Range Communications Satellite Phones and Radios MF/HF SSB Radio >>

  2. MF/HF SSB Radio >>

  3. MF/HF Overview • Basic Transmitter and Receiver • AM Transmitter and Receiver • SSB Transmitter and Receiver • MF/HF Antennas • MF/HF Licensing • MF/HF Operations • Summary >>

  4. Basic Transmitter and Basic Receiver >>

  5. Basic MF/HF Transmitter RF Heat Audio DC Audio - 300 to 3,000 Hz DC - 12 to 14 VDC @ 30A Medium Frequency / High Frequency Transmitter RF - 1.6 to 27.5 MHz Heat – a few watts >>

  6. AM Transmitter and AM Receiver >>

  7. AM Transmitter (Amplitude Modulation) Variable Oscillator Frequency Multiplier RF Amplifier (Frequency Selection) Modulator (Mike) PTT not shown Modulator varies voltage to RF Amplifier (Power) >>

  8. Amplitude Modulation • Inputs (examples are shown below) • 1 kHz (audio) • 10 MHz (RF) • Outputs • 1 kHz (audio in) • 9.999 MHz (10 MHz – 1 kHz) • 10 MHz (carrier in) • 10.001 MHz (10 MHz + 1 kHz) • Amplitude of sidebands (9.999 and 10.001 MHz) is proportional to audio volume • Frequency of sidebands (9.999 and 10.001 MHz) differ by audio frequency (1 kHz) >>

  9. Amplitude Modulation Amplitude vs Frequency Amplitude vs Time >>

  10. Frequency Modulation (Review) • Input • 1 kHz (audio) • 150 MHz (RF) • Output • 150 MHz (+/- 25 kHz) • Carrier shift (+/- 25 kHz) is proportional to audio volume • Rate of change, above and below carrier, is the same as the modulating audio frequency (1 kHz) >>

  11. AM TX Differences from FM TX • Modulator Power • AM requires lots of power (50% of RF Amp) • FM requires very little power • Efficiency • AM (Poor) • Carrier frequency carries no intelligence • Duplicated intelligence in each sideband • 100 watt transmitter has 25 watts of intelligence in one sideband • FM (Good) • Has all intelligence in carrier • 100 watt transmitter has 100 watts of intelligence >>

  12. AM Receiver (Antenna) (Speaker) aka Envelope Detector Audio Amplifier IF Amplifier RF Amplifier Mixer Demodulator (Volume Control) Local Oscillator (Frequency Selection) >>

  13. AM RX Differences from FM RX • AM Receiver does NOT have a limiter • Need changes in amplitude to get audio volume • Will get noise on weak signals • No squelch control • AM IF bandpass is narrower • AM IF (typically 455 KHz) +/- 3 KHz • FM IF (typically 10.7 MHz) +/- 5 KHz • AM does NOT have a capture effect • May hear two signals (stations) at once • AM Demodulator • Volume is derived from signal amplitude • Frequency is derived from how far sideband is from carrier >>

  14. SSB Transmitter and SSB Receiver >>

  15. SSB Transmitter (Single Sideband Modulation) Linear Amplifier Balanced Modulator Filter Mixer (Mike) Variable Oscillator Carrier Oscillator (Frequency Selection) PTT not shown >>

  16. SSB Modulation • Inputs • 1 kHz (audio) • 10 MHz (RF) • Outputs • 10.001 MHz (10 MHz + 1 kHz) • Amplitude of upper sideband (10.001 MHz) is proportional to audio volume • Frequency of sideband (10.001 MHz) is derived fromaudio frequency (1 kHz) >>

  17. Amplitude vs Frequency USB only No Carrier No LSB SSB Modulation Amplitude vs Time >>

  18. SSB TX DifferencesfromAM TX • Only transmits Upper Sideband • No carrier • No lower sideband • 6 db more efficient (for same power transmitter) • All intelligence resides in one sideband • Uses half the bandwidth >>

  19. SSB Receiver (Antenna) (Speaker) aka Product Detector Audio Amplifier IF Amplifier RF Amplifier Mixer Demodulator (Volume Control) Local Oscillator Beat Frequency Oscillator (Frequency Selection) (Clarifier) >>

  20. SSB RX DifferencesfromAM RX • IF amplifier bandwidth • AM is 6 kHz wide • SSB is 3 kHz wide • 3 db advantage to SSB (half the atmospheric noise) • Adds beat frequency oscillator • Takes place of carrier that is NOT transmitted • Clarifier is used to make voices sound human • SSB demodulator • AM is envelope detector • SSB is product detector >>

  21. SSB Transceiver • Transmitter and receiver are integrated into a single package 4.6” x 11.5” x 12.4” & 17.7lb >>

  22. MF/HF Antennas • Power Boat Antennas • Sail Boat Antennas • Antenna Tuner • Counterpoise • Transmission Line >>

  23. Power Boat Antennas • 23-foot fiberglass antenna • Metal antenna inside fiberglass cover • Requires • Intermediate support • Heavy-duty mount • Antenna tuner >>

  24. Real Fiberglass Antennas Actually fiberglass insulated metal antennas >>

  25. Sailboat Antennas • Normally an insulated backstay antenna • Minimum of 23 feet long • Requires • Backstay insulators • Antenna tuner 10” insulator for ¼” wire has 12,000 lbs breaking strength >>

  26. Real Backstay Antennas >>

  27. Antenna Tuners • Matches transceiver to antenna • Should be near antenna • Manual and automatic 9.1” x 13.4” x 3/1” & 6lb

  28. Counterpoise (ground plane) 3” x 0.003” • Recommend 100 sq ft of counterpoise • Power boats • Copper foil from antenna tuner to engines • Sailboats • Copper foil from antenna tuner to keel • Install copper foil inside below waterline • Bow to stern • On both sides • One or two runs • Connect to antenna tuner >>

  29. PL-239 RG-213 GTO-15 Transmission Line • Coax from transceiver to antenna tuner • RG-213 (50Ω) • PL-239 male connectors • Waterproof exposed RF connectors • High voltage wire from antenna tuner to base of antenna • GTO-15 (rated at 15,000 volts) • Want the shortest length possible >>

  30. 23 foot minimum Insulated Back Stay or 23’ vertical antenna RG-213 coax GTO-15 wire Transceiver Antenna Tuner 12-14 VDC @ 30A Counterpoise (3” wide copper foil) MF/HF SSB Installation Biggest fault with most marine MF/HF SSB installations is lack of sufficient counterpoise >>

  31. MF / HF Licensing • Operator License • Equipment License • Illegal Operations >>

  32. Operator License • FCC license required to transmit on MF/HF • Restricted Radiotelephone Operator Permit • On rules, regulations and procedures • Lifetime license • More details in chapter 5 >>

  33. Equipment License • FCC Ship Station License for MF/HF Transmitter (transceiver) • Ten year license • More details in Chapter 5 >>

  34. Illegal Operations • Using amateur radio transmitters on marine MF/HF frequencies • even if operator has a Restricted Permit • Modifying marine MF/HF transmitters to operate on amateur radio frequencies • It is legal to use marine MF/HF transmitters on amateur radio frequencies • provided operator has amateur radio license • equipment is unmodified >>

  35. Good Reference MF/HF Operations • Why MF/HF? • Who can you communicate with? • Frequency selection • Ship-to-Shore stations • Receive only services >>

  36. Why MF/HF? • Communications beyond VHF range • Advantages • Can broadcast to many stations at same time • No usage cost • unlike satellite communications • Disadvantages • Selecting right frequency is NOT easy • Communications are NOT private • Subject to atmospheric noise and fading • Equipment cost greater than satellite phone >>

  37. With whom can you communicate? • MF/HF voice comm similar to VHF-FM voice • Recreational boaters • Safety and operational needs • Commercial Ships • Safety and operational needs • Ship-to-Shore Stations • Safety and operational (USCG) • Personal and social • ShipCom • SailMail >>

  38. Frequency Selection (Review) • Marine bands: 2, 4, 6, 8, 12, 16, 18, 22 & 25 MHz • 2 MHz: day at least 100 nm, more at night • 4 MHz: day 20 to 250 nm, night 150 to 1,500 nm • 8 MHz: day 250 to 1,500 nm, night 400 to 3,000 nm • 12, 16, 18, 22 & 25 MHz: thousands of miles • Emergencies • 2182.0 kHz voice • 2187.5 kHz DSC • MF ground wave out to 250 miles • HF sky wave over 500 miles >>

  39. Ship-to-Shore Stations • Covered in Appendix C • USCG • ShipCom • SailMail • Covered in Appendix D • Pactor HF data Modem >>

  40. USCG 24/7 MF/HF Stations Communications Area Master Stations • Master Station Pacific • NMC @ Point Reyes, CA • NOJ @ Kodiak, AK • NMO @ Honolulu, HI • NRV @ Guam (not shown) • Master Station Atlantic • NMN @ Chesapeake, VA • NMF @ Boston, MA • NMA @ Miami, FL • NMG @ New Orleans, LA >>

  41. ShipCom HF Locations ShipCom Operations Center 24/7 in Mobile, AL • West Coast Radios • KLB @ Seattle • KNN @ Marina Del Ray • East Coast Radios • WLO @ Mobile • WCL @ New Jersey >>

  42. SailMail HF Locations SailMail provides HF email gateways • West Coast • WQAB964 @ San Diego, CA • WHV861 @ San Louis Obispo • WRD719 @ Palo Alto, CA • WHV382 @ Friday Harbor, WA • East Coast • XJN714 @ Nova Scotia • KZN508 @ Rockhill, SC • WPUC469 @ Daytona, FL • WPTG385 @ Corpus Christi >>

  43. NOAA Weather • Transmitted by USCG • Transmits NOAA / NWS weather forecasts • MF and HF voice • HF Facsimile • HF Teletype (SITOR modem) • Details in Appendix E >>

  44. WWV • Located at Ft. Collins, CO (N of Denver) • Broadcast on 2.5, 5.0, 10.0, 15.0 & 20.0 MHz • US frequency and time standard >>

  45. News • Near shore commercial AM • 535 to 1700 kHz • Voice of America (short wave) • BBC (short wave) • Good short wave band is 9.4 to 9.9 MHz >>

  46. MF/HF Summary • Marine MF/HF SSB systems consists of: • Transceiver, antenna tuner, antenna & counterpoise • For use beyond VHF line-of-sight communications • Requires a knowledgeable operator • SSB is more efficient than AM • MF/HF antenna requires • Antenna tuner • Counterpoise • MF/HF requires two licenses • Equipment (Ship Station) • Operator (Restricted Permit) >>

  47. Satellite Communications >>

  48. Overview • History • Advantage of Height • Orbits • Architecture • Communications Systems • (Phones, email and high end) • Specific Systems • (technical details) • Summary >>

  49. History 1945 Arthur Clark – Extra-Terrestrial Relays 1955 John Pierce – Mirror in Space 12 Aug 1960 – ECHO I 1962 – TELSTAR and RELAY 1982 - INMARSAT TELSTAR I RELAY I ECHO I >>

  50. Advantage of Height D (in nautical miles) = 1.32 * √ h (in feet) HeightRange (in nm) Remarks 100 feet 12.5 Antenna tower 250 feet 19.8 High antenna tower 100 miles over 900 500 miles over 2,000 Low Earth Orbit (LEO) 22,240 miles over 13,500 Geosynchronous Earth Orbit (GEO) GEO can see 1/3 of Earth’s surface! >>

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