High Latitude HF Comms Testing LT Mike Grochowski

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

What’s the Frequency, Kenneth? • Wi. Fi – 2. 4 GHz (2400 MHz) • AM Radio - ~1000 k. Hz (~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 These are the frequencies from 1. 8* to 30 MHz or the 160 meter to 10 meter bands. HF is also known as shortwave. *160 m is actually a Mid Frequency (MF) band but it is included in the Amateur HF bands for ease of discussion.

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 75 bps->19. 2 kbps under poor-> very good conditions, –From 2 -10 MHz, the noise environment can rise 33 – 70 d. B ABOVE thermal noise (k. TB) 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 -110 C Appendix D Data Waveform Suite (approved Sept 2011) supports HF Channel bandwidths ranging from 3 – 24 KHz in 3 k. Hz steps, allowing 75 bps -> 120 Kbps.

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

Hearing Signals Out of Thin Air

The Role of Sol How the Sun Opens and Closes The Bands

Why HF Works (The Atmosphere) The Earth’s atmosphere is made up of several layers or regions. D-Layer – Strong absorber of lowfrequency 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

Radio waves change direction when they enter the ionosphere

Sunspots / Solar Activity • More sunspots, the higher the ionization of the F 2 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, 000 miles commonplace using 10 watts or less with frequencies in the 20 – 30 MHz 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

Propagation There are three basic types of propagation of HF radio signals: 1. Sky-wave 2. Ground wave 3. High Angle Radiation (NVIS)

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

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.

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

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.

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

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

More about HF Amateur Radio ARRL Web Site -http: //www. arrl. org/what-s-ham-radio ARRL Power. Point “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-perturbation 6. htm HF Radiation - Choosing the Right Frequency http: //www. weather. nps. navy. mil/~psguest/EMEO_online/module 3/module_3_2 b. html Learning about Space Weather and Predicting HF Propagation http: //www. spacew. com/ HFALE http: //www. navymars. org/central/reg 4/al/ALE%20 Introduction. pdf Useful HF Noise Models complete with Formulas http: //ftp. rta. nato. int/public//Pub. Full. Text/RTO/TR/RTO-TR-IST-050///TR-IST-050 -02. pdf NVIS http: //tcares. org/tcares/images/presentations/nvis%20 propagation%20 theory. pdf

Questions? Ask this guy – Pager #819

Publications ARRL General Class License Manual http: //www. arrl. org/catalog/lm

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Publications ARRL Handbook http: //www. arrl. org/catalog/? item=9280

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Publications ON 4 UN's Low-Band DXing Antennas, Equipment and Techniques for DXcitement on 160, 80 and 40 m http: //www. arrl. org/catalog/7040/

Publications The Complete DX'er by Bob Locher, W 9 KNI http: //www. arrl. org/catalog/? item=9073

Publications On the Air with Ham Radio By Steve Ford, WB 8 IMY http: //www. arrl. org/catalog/? item=8276

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