Presentation on theme: "NVIS Communications Training Academy"— Presentation transcript:
1 NVIS Communications Training Academy Basic HF Voice Operator 1Introduction to HF-NVIS Radio CommunicationsIntroductory Radio PrinciplesWhy HF radio has become importantBasic HF Radio Technologiesqaxqw
2 Introductory Radio Principles Electromagnetic (EM) WavesEM Waves in the Radio SpectrumHigh Frequency (HF) in the radio spectrumNear Vertical Incident Skywave (NVIS)
3 Electromagnetic Waves Introductory Radio PrinciplesIt all starts with….Electromagnetic WavesThey are a fundamental, observable phenomenon in our universeMade of electric waves combined with magnetic waves.They travel through the universe at the speed of light. (they are light)They range in wavelength from radio waves, to visible light, and beyond.Image courtesy of NASAThe Electromagnetic Spectrum from radio waves, through visible light, and beyondWe are interested in waves at radio wavelengthsMFHFVHFUHFHowever, please feel free to use these wavelengths to watch this presentation.
4 The radio portion of the EM spectrum Introductory Radio PrinciplesThe radio portion of the EM spectrumVHF/UHF waves travel “line of sight”MF waves hug the groundHF waves refract from the ionosphereSpecial techniques are required beyond here“Shortwave”.3 MHz1000 m3 MHz100 m30 MHz10 m300 MHz1 m3 GHz.1 m30 GHz.01 mMFMedium FrequencyHFHigh FrequencyVHFVery High FrequencyUHFUltra High FrequencySHFSuper High FrequencyAlthough not technically correct, the “HF” radio band is often said to be from 1.6 to 30 MHz. instead of from 3 to 30 MHz. This is because most “HF” radios operate between 1.6 and 30 MHz.
5 About HF (High Frequency) Radio Waves Introductory Radio PrinciplesAbout HF (High Frequency) Radio WavesHF radio waves refract and reflect from the ionosphereIf directed toward the horizon they may go long distancesMaybe one hop, maybe manyMaybe short hops, maybe longGenerally includes dead “skip” zones
6 About NVIS (Near Vertical Incident Skywave) Introductory Radio PrinciplesAbout NVIS (Near Vertical Incident Skywave)An early NVIS mobileAn HF signal directed straight up will rain back down from the sky over hundreds of milesInstead of:
7 HF Long Distance vs. HF-NVIS Introductory Radio PrinciplesHF Long Distance compared to HF-NVISHF Long Distance vs HF-NVISIonosphereSkip zoneSignal zoneSignal spilledbeyond target areaRegional signal blanketIonosphereSpectrumre-usable elsewhereSignal toward the horizonHigh power, often 1KW+Antennas must be elevatedMay or may not workHas dead “skip” zonesSpills beyond intended areaMakes spectrum re-use difficultSignal straight upLow power, 125W is plentyAntennas stay near the groundVirtually always worksBlankets entire regionStays in the regional areaRe-assign spectrum elsewhere
8 Why its use faded and has now come back HF Past and PresentHF Past and PresentWhy its use faded and has now come back
9 The history of our use of the radio spectrum HF Past and PresentThe history of our use of the radio spectrumMFMedium FrequencyHFHigh FrequencyVHFVery High FrequencyUHFUltra High FrequencySHFSuper High Frequency-- Band usage past and present --AM RadioAmateur Radio,Shortwave Broadcast,MilitaryHF is important again for fallback communicationsLand Mobile Radio – Public Safety,business, governmentMicrowave, satellite, cellular,wireless devices, etc.1910s1920s1940s1930s1950s1960s……
10 HF radiation patterns are complicated (But now we have computers) HF Past and PresentHF radiation patterns are complicated (But now we have computers)HF signal paths are very complexTime of day, frequency, sunspots, …Historically the operator had to figure this outThat was not ideal for public safety personnelLocal government and industry moved to newer technologiesLocal communications went to VHF and UHFLong range went to T-carrier networks and the InternetBut the HF-NVIS story is like the “Flying Wing”Abandoned in 1950s because it was too complicatedCame back with computer control as the B2 bomberHF frequency rangeHF-NVIS is back under computer control the same way!
11 Migration from the Past to Today HF Past and PresentMigration from the Past to TodayThe PastTodayProducts from several vendorsLarge, heavy equipmentMarketed for the militaryFew vendors, very expensiveComplicated operationSpecially trained operatorsLimited featuresNot recognized for fallback useNot on the public safety radarNot known to critical infrastructuresSmaller lightweight equipmentMarketed for govt., public safetyCompeting vendors, cost effectiveSimpler, menu operationYour regular operational staffMany voice/data featuresThe new Base Layer Fallback modePublic safety lining up to get itCritical infrastructures want it
12 Why HF radio is critical for your future It has always been important for military, shortwave broadcast, and amateur radio.Now it is important again for government, public safety, and critical infrastructures
13 Fallback as opposed to Failover Why HF radio is critical for your futureFallback as opposed to FailoverPrimary Operational ModeFailover ModesFailover preserves the primary operational mode using alternate resources.Fallback replaces the primary mode with simpler modes when the primary mode is not available at all..Base Layer Fallback is your lowest layer of prepared fallback for when everything else has failed. It must not have components in common with the primary mode.Fallback Modes
14 Fallback for regional and wide-area communications Why HF radio is critical for your futureFallback for regional and wide-area communicationsPrimary systems:- Microwave, repeaters- Internet, PSTN- Hopefully FirstNet- …Failover MeasuresMany layers of alternate resources to keep the systems operational – Very important! However…These systems have many complex layers of infrastructure, and this makes them inherently subject to failure regardless of the their capabilities for failover.HF-NVIS systems have no intervening infrastructure between stations, and this makes them immensely more resilient.Modern, automated HF-NVIS networks are taking their rightful place as the Base Layer Fallback Mode for federal, state, and local government and for critical infrastructures.Critically needed Base Layer FallbackHF-NVIS
15 Why HF-NVIIS has become our nation’s Base Layer Fallback Mode Why HF radio is critical for your futureWhy HF-NVIIS has become our nation’s Base Layer Fallback ModeWe now realize how vulnerable our systems areLessons from 9-11, Katrina, Sandy, and othersWe now understand our need for Base Layer FallbackModern HF systems are available and easy to use“Simple menu operation for callingAutomatic frequency selection and call connectionCost effective for public safety useLeading edge agencies are adopting it!Federal, state, and local governmentsCritical Infrastructure providersHF-NVIS is becoming our National FallbackNet
16 You can build your own Base Layer Fallback Network Why HF radio is critical for your futureYou can build your own Base Layer Fallback NetworkNormal OperationsMicrowaveSatelliteInternetVHF/UHFLandlinesCellularPlan for these being compromisedOperational sites throughout your regional area
17 You can build your own Base Layer Fallback Network Why HF radio is critical for your futureYou can build your own Base Layer Fallback NetworkHave your own HF-NVIS network for selected staff personnelOperational sites throughout your regional area
18 You can build your own Base Layer Fallback Network Why HF radio is critical for your futureYou can build your own Base Layer Fallback NetworkHave your own HF-NVIS network for selected staff personnelInterface directly to disaster communications organizationsOperational sites throughout your regional area(Licensing restrictions apply)
19 From an article by BBC News Why HF radio is critical for your futureThink of HF-NVIS as a safety net under our infrastructure-heavy primary systemsThis net looks pretty makeshiftIt’s because they built it after the bear got stuck in the bridge.We should build ours before we get stuck!From an article by BBC News
20 Basic HF Radio Technology Single Sideband (SSB) ModulationHF antennas and the “dipole” antennaAutomatic Link Establishment (ALE)
21 HF Radio Modulation: Single Side Band (SSB) Basic HF Radio TechnologyHF Radio Modulation: Single Side Band (SSB)Modulation physics is beyond the scope of this classHowever, there are several things you should knowModulation means putting information (voice, etc.) onto a radio waveVHF/UHF voice systems typically use Frequency Modulation (FM)FM works great for local, “line-of-sight” communicationsBut SSB is the most effective modulation for long distancesUnfortunately, SSB does not block out noise the way FM does.SSB signal rides on top of the noise, so it is not as clear as FMBut for long distances, SSB will get through loud and clear where other modes will simply fail
22 SSB vs FM from the user’s perspective Basic HF Radio TechnologySSB vs FM from the user’s perspectiveA traditional 25 KHz-wide FM signal25 KHz wideFM captures its wide bandwidth with a carrier wave of energyFor this reason FM blocks out noise within its bandwidthThis is why a strong FM signal has no background noiseMany FM users have been required by the FCC to switch to “narrow band”12.5 KHz wideA “narrowband” (NFM) signal is half as wide, but it is still FMSingle Side Band is a sliver of energy vibrating within a 3KHz bandwidth3 KHz wideNo carrier wave to block out noise, so noise is always there. However…This narrow signal is easier to push long distances than a giant FM signal
23 HF Radio Antennas Basic HF Radio Technology Antenna physics is beyond the scope of this classHowever, there are several things you should knowAny wire or piece of metal can act as an antennaBut a good antenna is sized for the radio wavelength it will be used forVHF/UHF antennas can be short because VHF/UHF wavelengths are shortHF antennas must be long because HF wavelengths are longThe wavelength of a 5 MHz HF radio wave is approx. 60 meters.A “dipole” antennas is ideally 1/2 of the wavelength it is used forSo the ideal length for 5 MHz would be 30 meters or 98 feet.HF antennas are often shorter than ideal for practical reasons.
24 Two radiating elements extending in opposite directions. Basic HF Radio TechnologyThe Classic Dipole AntennaTwo radiating elements extending in opposite directions.Radiating elementRadiating elementDipole AntennaTransmission line1. The radio emits an alternating current at a some frequency.2. This creates alternating currents in the antenna elements3. This causes electromagnetic (radio) waves to radiate into space.Radio
25 Basic HF Radio Technology Dipoles as used in most applicationsMost installations use coaxial cable for transmission lineRadiating elementRadiating element“Balun”Easy to route to an antennaKeeps the radio signal inside until it reaches the antennaConsidered “unbalanced” because the two conductors inside it are not the same.It has an inner conductor and an outer shield.To feed a dipole, coaxial feed line needs an interface box called a “balun”This balances the coax signal equally between the two radiating elements.The physics of this are beyond the scope of this courseCoaxial cable
26 Common HF-NVIS Base Antennas Basic HF Radio TechnologyCommon HF-NVIS Base Antennas`Single wire dipole`Multi-wire dipolePortable dipoleMulti-wire dipoleMulti-wire dipole
27 Common HF-NVIS Mobile Antennas Basic HF Radio TechnologyCommon HF-NVIS Mobile AntennasBase tuned whip folded overLuggage rack half loopRoof mounted half loop
28 Automatic Link Establishment (ALE) Basic HF Radio TechnologyAutomatic Link Establishment (ALE)A peer-to-peer HF networkCompletely inside your radiosF1F2F4F3F5F6Your set of authorized HF frequencies that the radios scanSite 1Site 2Site 3Site 4
29 Automatic Link Establishment (ALE) Basic HF Radio TechnologyAutomatic Link Establishment (ALE)Scheduled soundingsEvery radio, will sound on every frequencyDynamic models of the optimum frequenciesF1F2F4F3F5F6A set of authorized HF frequencies that the radios scanrecording signal strengthSite 1 testingOn F1, On F2,On F3,Site 1Site 2Site 3Site 4
30 Automatic Link Establishment (ALE) Basic HF Radio TechnologyAutomatic Link Establishment (ALE)F1F2F4F3F5F6Place calls by unique radio ALE IDUser picks a contact from the listThe radios pick the best frequencyThe receiving radio(s) ring like a telephone.A set of authorized HF frequencies that the radios scanSite 1 calls Site 2 on the best frequencySite 2 rings like a telephoneSite 1Site 2Site 3Site 4
31 Voice, email, phone, SMS, fax Third party extensions for ICS form data Basic HF Radio TechnologyData modes, gateways, ease of useVoice, , phone, SMS, faxSite 1 HFSite 2 HFGatewaysPhone patchInternetFAXVHF/UHFGatewaysPhone patchInternetFAXVHF/UHFEasy to use- Menu operations- Auto freq. select- Auto connect- Contact lists- Press to call- Rings like phoneThird party extensions for ICS form dataICS
32 Basic use of your HF-NVIS system An hypothetical HF-NVIS networkListening to SSB radioTalking on SSB radioSignal reporting on SSB radioSquelch systems on SSB radio
33 An example HF-NVIS network SacramentoSan JoseLos AngelesRenoLas VegasBasic use of your HF-NVIS systemAn example HF-NVIS networkMobileDirect voice/data among all stations for hundreds of miles
34 An Example system test Basic use of your HF-NVIS system Las VegasLos AngelesAll stations stop scanning and ringNext week the test might be conducted by a different stationRenoSacramento places an ALE Group CallSan Jose“Sacramento now commencing this week’s all station roll call.“After roll call, all stations please send an HF to Sacramento.Sacramento
35 Any station can call any or all stations SacramentoSan JoseLos AngelesRenoLas VegasBasic use of your HF-NVIS systemDuring an emergencyAny station can call any or all stationsMobileSince the network is tested often, people will know how to use it, and it will work when needed!
36 Listening to SSB Radio Basic use of your HF-NVIS system You may be used to listening to FM radioGovernment and public safety radio is typically FMWith FM the voice volume tends to stay the same whether it is a strong or weak signalIf it is a strong signal, then there is no noise along with the voice. (“full quieting”)If it a weak signal, then the noise raises in volume until it drowns out the voiceSSB sound characteristics – opposite from FMWith SSB it is the noise volume (rather than the voice volume) that tends to stay the sameIf it is a strong signal, then the voice raises in volume and becomes louder than the noise.If it s weak signal, then the voice is lower in volume until it can no longer be heard through the noise
37 Talking on SSB Radio Basic use of your HF-NVIS system Use plain languageNo 10-codes or other service-specific jargonRemember, you may be talking with different services who do not know your jargonIf talking with other services, identify yourself with a full, descriptive identifierExample: “ Los Angeles County Sheriff Mobile Command Unit 1”Learn to say “over” before you release the mikeWe do not do this on FM because users can hear when your carrier dropsBut remember, there is no carrier for them to hear on SSB!So tell them when you are releasing the mike by saying “over”.Signing offSay your identifier then say “out” or “clear”On HF people usually use “out”, but either one describes your intentionSaying “over and out” may earn you some chuckles.
38 Signal reports on SSB radio Basic use of your HF-NVIS systemSignal reports on SSB radioYou may be used to giving signal report s on FM radio:For example “loud and clear”, “weak and scratchy”, “breaking up”, or “unable to copy”.But remember that SSB characteristics are differentThere is always noise, so saying “scratchy” is not informativeSignal would not normally “break up”, but it may fade slowly in and outSince the characteristics are different, signal reporting is different.A commonly used range for SSB signal reporting :“Loud and clear” (for a very loud signal)“Good readable”“Fair readable”“Weak readable”“Unable to copy”
39 Squelch systems for SSB Basic use of your HF-NVIS systemSquelch systems for SSBtheySquelch quiets the speaker when nothing is being receivedFM squelch detects the FM carrier of a received signalSSB has no carrier for a squelch system to detectSSB squelch therefore has to detect other thingsTypes of SSB squelchAudio squelch – tries to detect the characteristics of human voiceSignal squelch – detects increased signal level (could be just noise)Selective Call – activates only when the digital ID for that station is receivedUsing SSB squelchSSB audio squelch and signal squelch are not as effective as FM squelchMost people leave their radios on Selective Call to receive only calls to themAfter Selective Call activates, it typically leaves the speaker ON (no squelch)Most people leave the speaker on during calls to hear everythingThis is in contrast to FM, which squelches the speaker after each received signal
40 NVIS Communications Training Academy Congratulations on completing the classroom portion of:Basic HF Voice Operator 1Introduction to HF-NVIS Radio Communications.qaxqwPractical Exercises for this material will now follow.Subsequent courses will present more advanced topics.