MComm Ch7 - 1

Long Range CommunicationsLong Range Communications

MF/HF SSB Radio

Satellite Phones and Radios

>>

MComm Ch7 - 2

MF/HF SSB RadioMF/HF SSB Radio

>>

MComm Ch7 - 3

• Basic Transmitter and Receiver• AM Transmitter and Receiver• SSB Transmitter and Receiver• MF/HF Antennas• MF/HF Licensing• MF/HF Operations• Summary

MF/HF OverviewMF/HF Overview

>>

MComm Ch7 - 4

Basic Transmitterand

Basic Receiver

>>

MComm Ch7 - 5

Audio - 300 to 3,000 Hz

DC - 12 to 14 VDC @ 30A

Basic MF/HF TransmitterBasic MF/HF Transmitter

Medium Frequency

/ High Frequency

Transmitter

Audio

DC

RF

Heat

RF - 1.6 to 27.5 MHz

Heat – a few watts

>>

MComm Ch7 - 6

AM Transmitterand

AM Receiver

>>

MComm Ch7 - 7

AM TransmitterAM Transmitter(Amplitude Modulation)

Variable

Oscillator

Frequency

Multiplier

RF

Amplifier

Modulator(Mike)

(Power)Modulator varies voltage to RF Amplifier

(Frequency

Selection)

PTT not shown

>>

MComm Ch7 - 8

• 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)

Amplitude ModulationAmplitude Modulation

>>

MComm – Ch7 - 9

Amplitude ModulationAmplitude Modulation

Amplitude vs Time

>>

Amplitude vs Frequency

MComm Ch7 - 10

• 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)

Frequency ModulationFrequency Modulation(Review)

>>

MComm Ch7 - 11

• 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

AM TX Differences from FM TXAM TX Differences from FM TX

>>

MComm Ch7 - 12

AM ReceiverAM Receiver

RF Amplifier Mixer

IF Amplifier

Audio

Amplifier

Local

Oscillator

Demodulator

(Antenna) (Speaker)

(Frequency

Selection)

(Volume

Control)

aka

Envelope

Detector

>>

MComm Ch7 - 13

• 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

AM RX Differences from FM RXAM RX Differences from FM RX

>>

MComm Ch7 - 14

SSB Transmitterand

SSB Receiver

>>

MComm Ch7 - 15

SSB TransmitterSSB Transmitter(Single Sideband

Modulation)

Balanced Modulator

(Mike)

(Frequency

Selection)

Filter MixerLinear

Amplifier

Carrier

Oscillator

Variable

Oscillator

PTT not shown

>>

MComm Ch7 - 16

• 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 from audio frequency (1 kHz)

SSB ModulationSSB Modulation

>>

MComm – Ch7 - 17

SSB ModulationSSB Modulation

Amplitude vs Time Amplitude vs Frequency

USB only

No Carrier

No LSB

>>

MComm Ch7 - 18

• 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

SSB TX Differences from AM TXSSB TX Differences from AM TX

>>

MComm Ch7 - 19

SSB ReceiverSSB Receiver

RF Amplifier Mixer

IF Amplifier

Audio

Amplifier

Local

Oscillator

Demodulator

(Antenna) (Speaker)

(Frequency Selection)

(Volume Control)Beat

Frequency

Oscillator

(Clarifier)

aka

Product

Detector

>>

MComm Ch7 - 20

• 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

SSB RX Differences from AM RXSSB RX Differences from AM RX

>>

MComm Ch7 - 21

SSB TransceiverSSB Transceiver• Transmitter and receiver are

integrated into a single package

4.6” x 11.5” x 12.4” & 17.7lb>>

MComm Ch7 - 22

• Power Boat Antennas• Sail Boat Antennas• Antenna Tuner• Counterpoise• Transmission Line

MF/HF AntennasMF/HF Antennas

>>

MComm Ch7 - 23

Power Boat AntennasPower Boat Antennas

• 23-foot fiberglass antenna Metal antenna inside fiberglass cover

• Requires Intermediate support Heavy-duty mount Antenna tuner

>>

MComm Ch7 - 24

Real Fiberglass AntennasReal Fiberglass AntennasActually fiberglass insulated metal

antennas

>>

MComm Ch7 - 25

Sailboat AntennasSailboat 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>>

MComm – Ch7 - 26

Real Backstay AntennasReal Backstay Antennas

>>

MComm Ch7 - 27

Antenna TunersAntenna Tuners

• Matches transceiver to antenna• Should be near antenna• Manual and automatic

9.1” x 13.4” x 3/1” & 6lb

MComm Ch7 - 28

• 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

Counterpoise (ground plane)Counterpoise (ground plane)

>>3” x 0.003”

MComm Ch7 - 29

Transmission LineTransmission 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

>>RG-213 PL-239 GTO-15

MComm Ch7 - 30

MF/HF SSB InstallationMF/HF SSB Installation

Biggest fault with most marine MF/HF SSB installations is lack of sufficient counterpoise

RG-213 coax

23 foot minim

um

Insulated Back S

tay

Counterpoise (3” wide copper foil)

12-14 VDC @ 30A

GTO-15 wire

>>

23’ vertical antenna

or

Antenna

TunerTransceiver

MComm Ch7 - 31

MF / HF LicensingMF / HF Licensing

• Operator License• Equipment License• Illegal Operations

>>

MComm Ch7 - 32

Operator LicenseOperator 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

>>

MComm Ch7 - 33

Equipment LicenseEquipment License• FCC Ship Station License

for MF/HF Transmitter (transceiver) Ten year license

• More details in Chapter 5

>>

MComm Ch7 - 34

• 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

Illegal OperationsIllegal Operations

>>

MComm Ch7 - 35

MF/HF OperationsMF/HF Operations

• Why MF/HF?• Who can you

communicate with?• Frequency selection• Ship-to-Shore

stations• Receive only

services

>>Good Reference

MComm Ch7 - 36

• 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

Why MF/HF?Why MF/HF?

>>

MComm Ch7 - 37

• 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

With whom can you communicate?With whom can you communicate?

>>

MComm Ch7 - 38

• 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

Frequency SelectionFrequency Selection(Review)

>>

MComm Ch7 - 39

• Covered in Appendix C USCG ShipCom SailMail

• Covered in Appendix D Pactor HF data Modem

Ship-to-Shore StationsShip-to-Shore Stations

>>

MComm Ch7 - 40

• Master Station Pacific NMC @ Point Reyes, CA NOJ @ Kodiak, AK NMO @ Honolulu, HI NRV @ Guam (not shown)

USCG 24/7 MF/HF StationsUSCG 24/7 MF/HF Stations

• Master Station Atlantic• NMN @ Chesapeake, VA• NMF @ Boston, MA• NMA @ Miami, FL• NMG @ New Orleans, LA

Communications Area Master Stations

>>

MComm Ch7 - 41

ShipCom HF LocationsShipCom HF Locations

• West Coast Radios– KLB @ Seattle– KNN @ Marina Del Ray

ShipCom Operations Center 24/7 in Mobile, AL

• East Coast Radios– WLO @ Mobile– WCL @ New Jersey

>>

MComm Ch7 - 42

• West Coast WQAB964 @ San Diego, CA WHV861 @ San Louis Obispo WRD719 @ Palo Alto, CA WHV382 @ Friday Harbor, WA

SailMail HF LocationsSailMail HF Locations

• East Coast• XJN714 @ Nova Scotia• KZN508 @ Rockhill, SC• WPUC469 @ Daytona, FL• WPTG385 @ Corpus Christi

SailMail provides HF email gateways

>>

MComm Ch7 - 43

• Transmitted by USCG

• Transmits NOAA / NWS weather forecasts MF and HF voice HF Facsimile HF Teletype (SITOR modem)

• Details in Appendix E

NOAA WeatherNOAA Weather

>>

MComm Ch7 - 44

WWVWWV• 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

>>

MComm Ch7 - 45

• 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

NewsNews

>>

MComm Ch7 - 46

• 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)

MF/HF SummaryMF/HF Summary

>>

MComm Ch7 - 47

Satellite CommunicationsSatellite Communications

>>

MComm Ch7 - 48

• History• Advantage of Height• Orbits• Architecture• Communications Systems

(Phones, email and high end)

• Specific Systems (technical details)

• Summary

OverviewOverview

>>

MComm Ch7 - 49

HistoryHistory• 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 IECHO I

MComm Ch7 - 50

D (in nautical miles) = 1.32 * √ h (in feet)

Height Range (in nm) Remarks

100 feet 12.5 Antenna tower250 feet 19.8 High antenna tower100 miles over 900500 miles over 2,000 Low Earth Orbit (LEO)22,240 miles over 13,500Geosynchronous

Earth Orbit (GEO)

GEO can see 1/3 of Earth’s surface!

Advantage of HeightAdvantage of Height

>>

MComm Ch7 - 51

• Low Earth Orbit (LEO) constellation 25 to 75 satellites in orbits from 450 to 900 nm Period around 100 minutes (from 500 miles)

Each satellite is visible for approx 15 minutes

• Geostationary Earth Orbit (GEO) constellation 4 satellites in stationary 19,330 nm orbits Period 23 hours and 56 minutes The same 1 or 2 satellites are always visible

OrbitsOrbits

>>

MComm Ch7 - 52

• Bent Pipe

• Store and Forward

• Switched with Cross Links

ArchitectureArchitecture

>>

MComm Ch7 - 53

• Communications satellite is a real-time radio relay All “smarts” are on the ground “Dumb” satellite, transmits all data that it receives

• User & Ground Station have to see same satellite At the same time Latency is waiting for a satellite to come into view

Bent-PipeBent-Pipe

TerminalTerrestrial

CommunicationsUser 1

EarthStation

Satellite 1

User 2

Satellite 2

>>

MComm Ch7 - 54

Store-and-ForwardStore-and-Forward

• Comm satellite is a store-and-forward radio relay• Can save received data until it sees a ground station• Most “smarts” are on the ground• Satellite transmits all that it receives to the ground station

• User and ground station have to see same satellite• But NOT at the same time; may be minutes of latency

User 2

Satellite 2Satellite 1at time 1

User 1 TerminalTerrestrial

Communications

EarthStation

Satellite 1at time 2

>>

MComm Ch7 - 55

Switched or Cross-linkedSwitched or Cross-linked

• Communications satellite decodes & switches data• “Smart” satellite• Considerable “smarts” still on the ground

• After decoding data, the communications satellite:• Switches data to another satellite user• Switches and cross-links data to another satellite• Switches data to ground station

TerminalTerrestrial

Communications

EarthStation

User 1 User 2 User 3

Satellite 1 Satellite 2

>>

MComm Ch7 - 56

• Satellite phones

• Email only (packet data)

• High end data and voice

General SystemsGeneral Systems

>>

MComm Ch7 - 57

• Iridium (LEO Satellite Phone)

• IsatPhone (GEO Satellite Phone)

• SkyMate via Orbcomm (LEO data / email)

• Inmarsat (High end system) mini-C (GEO data / email) mini-M (GEO voice and data / email)

Specific SystemsSpecific Systems

>>

MComm Ch7 - 58

Satellite Phone - IridiumSatellite Phone - Iridium• 66 LEOs at 420 nm

Orbits: 86.4º with 100 min period Weight: 1,500 lbs

• Voice and data at 2400 bps• Switching in sky (with cross links)

13.2 oz 1,500 lbs>>

MComm Ch7 - 59

• Worldwide coverage• (8816 or 8817) + 8-digit phone number• Purchase (or lease) handset, service from VAR• Antenna must be outside

Pointed straight up With clear view of sky Some installations use external antenna

• 9505 handset gives 3.8 hr TX & 35 hr standby

• Cost Handset ≈ $1,400 $20 a month plus $1 to $1.50 per minute

Iridium - 2Iridium - 2

>>

MComm Ch7 - 60

Iridium VariantsIridium Variants

Fixed Iridium transceiver, handset/remote and remote antenna

>>

Iridium 9505 docking station and remote antenna

MComm Ch7 - 61

Satellite Phone - IsatPhoneSatellite Phone - IsatPhone

• Satellite Phone service by INMARSAT Only from 4th generation GEO I-4

satellites 12,000 lbs and 13 kW of power

• Dual mode phone 2400 bps satellite phone 9600 GSM cell phone

>>

MComm Ch7 - 62

• Currently coverage only in Indian Ocean• Purchase (or lease) handset, service from

VAR• Antenna must be outside

Pointed straight up With clear view of sky

• Handset give 2.7 hr TX and 42 hr standby• Cost

Handset ≈ $600 $1 per minute

IsatPhone - 2IsatPhone - 2

>>

MComm Ch7 - 63

IsatPhone CoverageIsatPhone Coverage

• July 07 Coverage Region in brown From I-4 F1 (64º E)

• By end of 2009 expect global coverage 40º N to 40º S from all 4 I-4s

>>

MComm Ch7 - 64

Email - SkyMateEmail - SkyMate• SkyMate is a VAR for Orbcomm

• Orbcomm has 29 LEOs at 515 miles 4 orbits and 28 satellites inclined at 45º 1 orbit in near-polar orbit Weight 92 lbs, power 160 W

• Data packets (email) only 2400 bps up 4800 bps down

• Bent Pipe architecture

>>

MComm Ch7 - 65

SkyMate - 2SkyMate - 2• SkyMate provides

Email delivered as voice or fax Position reporting (requires interface with GPS) Customized weather forecasts Remote vessel monitoring (extra HW and SW)

• Fixed installation External antenna User provided PC and GPS

• Cost HW and SW start at $1,200 $18/month for 8,000 characters

>>

MComm Ch7 - 66

Orbcomm/SkyMate CoverageOrbcomm/SkyMate Coverage

• Current (2007) coverage in brown• Planned late 2008 coverage addition in

blue>>

MComm Ch7 - 67

SkyMate InstallationSkyMate Installation• Antenna needs good view of sky

Located within 30 foot coax run of transceiver

SkyMate 100 Transceiver

GPS

(user supplied)

PC

(user supplied)+ 12 VDC

Message indicator light

coax

serial datacable

pig tailadapter

GPS datacable

Main harness assy.

>>

MComm Ch7 - 68

INMARSAT mini-C and mini-MINMARSAT mini-C and mini-M

>>

MComm Ch7 - 69

Email – INMARSAT mini-CEmail – INMARSAT mini-C• 4 Bent Pipe GEOs at 19,330 nm• E-mail packet data at 600 bps

Also X.25 protocol from PC to PC

• Requires user-provided PC (RS-232 interface)

• Unstabilized antenna (6 inches high; 2.4 lbs)

• Cost eTRAC terminal (HW and SW) ≈ $2,000 1¢ per character

>>

MComm Ch7 - 70

INMARSAT mini-C CoverageINMARSAT mini-C Coverage• Basically 70º north to 70º south

>>

MComm Ch7 - 71

mini-C Installationmini-C Installation• Antenna needs good view of sky

PC is user-provided

User provided PC

with

eTRAC software

>>

MComm Ch7 - 72

Voice & Email INMARSAT mini-MVoice & Email INMARSAT mini-M• 4 GEOs at 19,330 nm• Voice and Email packet data at 2400 bps

Also X.25 protocol from PC to PC• Requires user-provided PC (RS-232 interface)

• 3-axis stabilized antenna (11.5-inches high; 11 lbs)

• Cost Tracphone 252 (HW and SW) ≈ $4,700 $1.49 per minute with no monthly fee

>>

MComm Ch7 - 73

INMARSAT mini-M CoverageINMARSAT mini-M Coverage• mini-M coverage is in blue (from spot beam

coverage) Some mid-ocean gaps south of the equator Red dots are Land Earth Stations

>>

MComm Ch7 - 74

• Architecture Bent Pipe Store and Forward Switched and cross-linked

• Satellite Phone Iridium IsatPhone (today Indian Ocean only)

Scheduled for worldwide by end of 2009

• Email SkyMate (value added to Orbcomm) Inmarsat mini C and mini M (high end

users)

SummarySummary

>>