1. HF Propagation An Introduction for the Newcomer By Gary Sutcliffe, W9XT Copyright (c) 2008 Gary C. Sutcliffe

2. Topics What are the HF Bands? How HF Propagation works Band by Band Overview Operating HF 2W9XT

3. Amateur Bands A range of frequencies. Different modes allowed on different frequency ranges of the band Usually referred to by wavelength i.e. “40 Meters” Historical – in early days of radio wavelengths were used to designate frequency Wave length = 300/frequency in MHz 3W9XT

4. The High Frequency Bands HF ranges from 3-30 MHz Traditional Bands WARC Bands 160M* 1.80-2.00 MHz 80M 3.50-4.00 MHz 40M 7.00-7.30 MHz 20M 14.00-14.350 MHz 15M 21.00-21.450 MHz 10M 28.00-29.700 MHz *Technically MF 30M 10.10-10.15 MHz 17M 18.068-18.168 MHz 12M 24.890-24.990 MHz 4W9XT

5. The Ionosphere Caused when UV light knocks electrons off air molecules Varies with Solar flux (number of sunspots) ‏ Season Time of day 5W9XT

6. HF Propagation Via the Ionosphere MUF – Maximum Usable Frequency 6W9XT

7. Ionosphere Layers 7W9XT

8. D Layer Caused by UV light Forms during the day Disappears at night Absorbs lower frequency signals 8W9XT

9. E Layer Thought to be caused by wind shear Not usually there Can last minutes to hours Most common May-July Can be very intense Usually effective 50 MHz (6 Meters) ‏ and below Rare at 144 MHz (2 Meters) and above 9W9XT

10. F Layer Responsible for most HF propagation Caused by UV light from sun Forms during day, dissipates at night MUF varies with ionization level Sometimes splits into F 1 and F 2 during the day 10W9XT

11. Ionization and the Sun Ionization level corresponds closely to sun spots Sun spots follow an 11 year cycle Sun spots range from 0 to ~ 150 Smoothed number used Solar flux – 10.7 cm radiation Ranges from ~60 to ~250 11W9XT

12. Geomagnetic Field Indicates stability of magnetic field of Earth Reported as A & K indices A Planetary index K single site Low index = stable / high index = unstable Solar flares cause high A & K High A & K often result in auroras absorption of radio waves on polar paths 12W9XT

13. Propagation Numbers Sources WWV 18 minutes after the hour Various Internet sites High SF (solar flux) means higher MUF Need high numbers for 10 & 15 Meters to open Lower levels best for 160 & 80 Meter DXing Low A & K mean Geo-magnetic field stability Needed for polar paths (mid-west USA to Europe, Japan) North-South paths not affected as much by geomagnetic field 13W9XT

14. Paths Radio Wave Follow Normally follows great circle path Long path – the long way around the world Most common on 40 - 15 Meters Back Scatter – no direct path open Signals scatter off area with common propagation Gray Line Low frequency signals follow terminator Sunrise or sunset at each end 14W9XT

15. Sporadic E (E s )‏ Can happen any time Most common May-July Secondary peak period Dec-Jan Most apparent on 10 Meters Up to ~1500 miles, multi-hop possible Openings can be very localized or wide spread Can result in very strong signals 15W9XT

16. 160M Day – Local to a few hundred miles Night – Long distances possible Often noisy (static) ‏ A very challenging DX band Antennas difficult because of size – Dipole ~260' Technician: No operation permitted 16W9XT

17. 80 Meters Day – Local to several hundred miles Night – World wide possible Often noisy (static) ‏ Challenging DX band Phone band sometimes called 75 Meters Popular band for nets Antennas difficult in small lot – Dipole ~ 133' Technician: CW 17W9XT

18. 40 Meters Day – Local to 1000 miles or more Night – World wide possible A reliable band – almost always open somewhere Antennas manageable Dipole ~ 66' Verticals with good radials effective DX antenna Beams large but manageable with heavy duty rotor Technician: CW 18W9XT

19. 30 Meters Day- 1000 miles or more Night - World wide possible Similar to 40M Antennas manageable Dipole ~46' Vertical very effective DX antenna WARC Band, CW & Data only, 250W max Technician: No operation permitted 19W9XT

20. 20 Meters Day – 500 miles to world wide Night -World wide possible Considered by some as best DX band Antennas manageable Dipole - ~33' Beams common Technician: No operation permitted 20W9XT

21. 17 Meters Day - hundreds of miles to world wide Night – open world wide with high sunspot levels Good band for beginning DXer Antennas Dipole ~ 25' Beams manageable WARC Band Technician: No operation permitted 21W9XT

22. 15 Meters Day – Hundreds of miles to world wide Night – Stays open late with high sunspot levels Great DX band in moderate-high sunspot years Antennas Dipole ~22' Beams common Technician: CW 22W9XT

23. 12 Meters Day - Hundreds of miles to world wide Night – open only in high sunspot years Great DX band in high sunspot years Antennas Dipole ~18' Beams helpful WARC Band Technician: No operation permitted 23W9XT

24. 10 Meters Day - Hundreds of miles to world wide Night – open several hours in high sunspot years Excellent DX band in high sunspot years Very quiet Modest stations effective Very large – stations can spread out to avoid QRM Antennas Dipole ~18' Beams common 24W9XT

25. 10 Meters (continued) Many propagation modes F (with moderate to high sunspot levels) ‏ E s Aurora Technician: CW, data, phone 25W9XT

26. HF Operating Activities Rag chewing DXing Contesting Awards – DXCC, WAS, WAC, etc. Special event stations Nets – Formal & Informal Modes: SSB, CW, RTTY, PSK31, SSTV, more 26W9XT

27. Operating HF Three rules for HF operating Listen 27W9XT

28. HF Operating (continued) Operation not channelized Watch band edges! No one owns a frequency Avoid interfering with other stations Ask if a frequency is in use before transmitting 28W9XT

29. Phone operation Single Side Band (SSB) ‏ Lower Side Band (LSB)160, 80 & 40 Upper Side Band (USB) 20, 17, 15, 12, & 10 Watch band edges Low end on LSB High end on SSB 29W9XT

30. Phone Operation (continued)‏ Learn and use standard phonetics for call signs Use full call signs for ID 30W9XT

31. HF QSOs Normally start with a CQ Keep CQs short, 3 X 3 is fine Answer CQ with his call sign followed by yours 1-2 times 31W9XT

32. DX QSOs Follow his lead – don't attempt to rag chew if he is only handing out signal reports. Listen and follow his instructions for calling In a pile up give your full call sign once phonetically then listen 32W9XT

33. Learning Propagation Get on the air! Get on different bands at different times NCDXF Beacons http://www.ncdxf.org/beacons.html Beacons on 20, 17,15, 12 & 10 meters Propagation Prediction Programs W6EL ITS HF Prop W9XT33

34. Learning Propagation (continued) Operating activities that help learn propagation Work on awards Worked All States DXCC – work 100 countries Contests The increased activity gives a good indication of band openings W9XT34

35. Summary HF provides a life time of challenges and fun Opens the whole world 35W9XT