1 / 27

High Latitude HF Comms Testing

High Latitude HF Comms Testing. LT Mike Grochowski Bill Jankowski USCG RDC. What ’ s the Frequency, Kenneth?. WiFi – 2.4 GHz (2400 MHz) AM Radio - ~1000 kHz (~1 MHz) FM Radio - ~100 MHz (0.1 GHz) Cell Phones (850/900/1,800/1,900 MHz). What Does HF Mean?. HF stands for HIGH FREQUENCY

abram
Download Presentation

High Latitude HF Comms Testing

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. High Latitude HF Comms Testing LT Mike Grochowski Bill Jankowski USCG RDC

  2. What’s the Frequency, Kenneth? • WiFi – 2.4 GHz (2400 MHz) • AM Radio - ~1000 kHz (~1 MHz) • FM Radio - ~100 MHz (0.1 GHz) • Cell Phones (850/900/1,800/1,900 MHz)

  3. What Does HF Mean? HF stands for HIGH FREQUENCY These are the frequencies from 1.8* to 30 MHz or the 160 meterto 10 meter bands. HF is also known as shortwave. *160m is actually a Mid Frequency (MF) band but it is included in the Amateur HF bands for ease of discussion.

  4. Ok, if HF is so Great, why doesn't everyone use it?? • HF propagation is impacted by the actions of the Sun via “Sunspots” • Data throughputs from 75bps->19.2kbps under poor-> very good conditions, • From 2-10MHz, the noise environment can rise 33 – 70dB ABOVE thermal noise (kTB) due to manmade and atmospherics„ (fluorescent lights, T- storms, fish tanks, electric fences, Xmas lights, old electric motors, etc) • Common perception is that data rates are “low” and antennas are LARGE • Breaking NEWS: MIL-STD-188-110C Appendix D Data Waveform Suite (approved Sept 2011) supports HF Channel bandwidths ranging from 3 – 24KHz in 3kHz steps, allowing 75bps -> 120Kbps.

  5. How is HF different other communications methods? • No “machine” or infrastructure is used. HF Takes advantage of atmospherics • Allows communication beyond line of sight WITHOUT Satellites or repeaters. Links can be a couple of hundred miles to over several thousand miles. • Propagation is strongly effected by solar activity. • Several communication modes are available to use. SSB, CW, RTTY, SSTV, Digital, AM

  6. Hearing Signals Out of Thin Air

  7. The Role of SolHow the Sun Opens and Closes The Bands

  8. Why HF Works(The Atmosphere) • The Earth’s atmosphere is made up of several layers or regions. D-Layer – Strong absorber of low-frequency HF energy during the day E-Layer – Reflects mid frequencies of HF (10-30 MHz) during the day F-Layer – Strong reflector of lower-frequency HF

  9. Radio waves change direction when they enter the ionosphere

  10. Sunspots / Solar Activity • More sunspots, the higher the ionization of the F2 Layer • 11 year cycle • Solar storms (intense cosmic activity) can change the critical frequency in a matter of minutes -> hrs– One minute the link is fine, in a matter of minutes, its GONE • Sunspot maximum - 10,000miles commonplace using 10watts or less with frequencies in the 20 – 30MHz range. • Sunspot Activity has stayed well below maximum • During short summer evenings, the MUF can stay above 14 MHz and it can support communications to some point in the world around the clock. • Similarly, during long winter evenings, MUF plummets and HF Distances shorten

  11. Propagation There are three basic types of propagation of HF radio signals: • Sky-wave • Ground wave • High Angle Radiation (NVIS)

  12. Sky-Wave Provides Single (<4000km) or Multi-hop (7 hops, 15,000km) communications via ionospheric reflections * * Very, very old picture – D Layer attenuates; it’s the E and F layers that reflect

  13. The Gray Line The transition are between daylight and darkness is called the gray line. This area offers some unique and special propagation to the radio operator.

  14. Ground Wave Ground wave is the signal that radiates close to the ground from the Earth’s surface up to the lower atmosphere or troposphere and is reflected or diffracted by the terrain. - ~200-300 NM

  15. NVIS - Near Vertical Incidence Sky-wave Like squirting a hose at the ceiling, this technique allows you to blanket your signals over a significant area close to your station.

  16. OK, Physics, Great – Why does the USCG Care? • GMDSS – Global Maritime Distress and Safety System • Uses DSC (Digital Selective Calling) tied to ship’s MMSI • GOTHAM and COTHEN • HF ALE (Automated Link Establishment) networks • HF Secure Voice Network

  17. Got it.Why does HEALY 1403 care? RDC study of existing Alaska HF sites identified areas where coverage could be improved Temporary deployment to Barrow this summer Considering additional fixed sites Multiple Measurements using existing fixed sites and Healy allow for better modeling in future efforts

  18. More about HF • Amateur Radio • ARRL Web Site -http://www.arrl.org/what-s-ham-radio • ARRL PowerPoint “Discover The Magic of HF Radio” • http://www.barriearc.com/CBSS_ARES_files/HF-Radio.pdf • http://www.emergencyradio.ca/course/HF-Radio.ppt • Low Band Dx‟ing – probably the best source of ALL THINGS HF you‟ll ever need • http://vss.pl/lf/00.pdf • HF Propagation and Propagation Prediction • –  VOACAP Website • http://www.astrosurf.com/luxorion/qsl-perturbation6.htm • HF Radiation - Choosing the Right Frequency • http://www.weather.nps.navy.mil/~psguest/EMEO_online/module3/module_3_2b.html • Learning about Space Weather and Predicting HF Propagation • http://www.spacew.com/ • HFALE • http://www.navymars.org/central/reg4/al/ALE%20Introduction.pdf • Useful HF Noise Models complete with Formulas • http://ftp.rta.nato.int/public//PubFullText/RTO/TR/RTO-TR-IST-050///TR-IST-050-02.pdf • NVIS • http://tcares.org/tcares/images/presentations/nvis%20propagation%20theory.pdf

  19. Questions? Ask this guy – Pager #819

  20. PublicationsARRL General Class License Manual http://www.arrl.org/catalog/lm

  21. Morse Code Study Materials http://www.arrl.org/catalog/lm

  22. PublicationsARRL Handbook http://www.arrl.org/catalog/?item=9280

  23. PublicationsARRL Antenna Book http://www.arrl.org/catalog/?item=9043

  24. PublicationsON4UN's Low-Band DXing Antennas, Equipment and Techniques forDXcitement on 160, 80 and 40m http://www.arrl.org/catalog/7040/

  25. PublicationsThe Complete DX'erby Bob Locher, W9KNI http://www.arrl.org/catalog/?item=9073

  26. PublicationsOn the Air with Ham RadioBy Steve Ford, WB8IMY http://www.arrl.org/catalog/?item=8276

  27. PublicationsRF Exposure and YouBy Ed Hare, W1RFI http://www.arrl.org/catalog/?item=6621

More Related