Hey What’s That? How to ‘get out’ better from your QTH David Aslin G3WGN TARS Meeting September 30th 2016

In G3WGN’s dreams  720 kHz AM Chicago, Illinois Might play well on 1820kHz or 3510kHz ?

Current G3WGN reality The long march is over: New G3WGN QTH in TQ9 is under construction Assessed approx. 180 potential QTHs Studied in depth approx. 50 Detailed analysis of 12 Prime criteria: XYL enthusiasm DX and contesting potential No refurb project needed X X

Improving your station’s HF performance Move antenna closer to a downslope or away from an obstacle to optimise performance Raise antenna – 5-10ft may make a big difference Change antenna type for one that better suits your QTH and desired DX performance Locate a portable or holiday location or pick a Field Day or SES site Plan a DXpedition antenna layout Analyse a site for a remote station Move QTH

Improving your station’s HF performance What take-off angle(s) do I need for best signal strength? What take-off angle does my antenna provide? What is the effect of local terrain on my signals? Can I do anything to optimise these factors? How can I work out best antenna location, type and height to fit my QTH and budget?

What take-off angle(s) do I need? Improving your station’s HF performance What take-off angle(s) do I need?

Take Off Angle Elevation angle in degrees = atanh (h/d) Height of obstruction (h) TOA Distance to obstruction (d) Elevation angle in degrees = atanh (h/d)

What take-off angle(s) do I need? WGN Chicago “Modern Radio Marvel” The Chicago Sunday Tribune July 23, 1939

What take-off angle(s) do I need?

What take-off angle(s) do I need?

What take-off angle(s) do I need? Percentage of QSOs G-JA at or below the specified TOA e.g. 8.9% of all G-JA QSOs on 17m take place at a TOA of 1 degree or less Percentages are cumulative e.g. on 17m, 44.2% of all G-JA QSOs take place at an elevation angle of 5 degrees or less (8.9+11.1+10.0+6.4+7.8 = 44.2%) Extracted from ARRL Antenna Book 23rd Edition CD-ROM

% of total G-W4 QSOs on 20m (Y-axis) occurring below specified Elevation Angle (X-Axis)

What TOA does my antenna provide? Improving your station’s HF performance What TOA does my antenna provide?

What TOA does my antenna provide? 40m antenna Elevation Patterns Red trace: 1/4λ vertical Blue trace: dipole at 35ft

What TOA does my antenna provide? OCFD at 35ft OCFD on 20m at 35ft

What TOA does my antenna provide? 20m dipole at 20ft and 42ft

What TOA does my antenna provide? 20m Elevation pattern: Hexbeam at 30ft versus 1/4λ vertical

Putting antenna and path TOA together 30m antennas at 50ft Elevation coverage Red trace: 2-El Yagi Blue trace: dipole

What is the effect of local terrain?

What is the effect of local terrain? Signals are reflected, diffracted and refracted by land and water features Full analysis requires the use of satellite topographical data plus ray tracing geometry HF Terrain Assessment (HFTA) software by N6BV analyses all directions (in 1⁰ increments) and paths out to 4.4km or more at 30m intervals. W6NL recommends at least 20x antenna height. Results are invaluable for choosing the location and height of antennas for specific paths, but HFTA involves significant complexity. See K6TU’s site for some insights and tools. Is there a simpler way?

HeyWhat’sThat? www.heywhatsthat.com Developed for ‘name that peak’ Multiple amateur radio applications for HF and VHF/UHF Used extensively to evaluate sites for 6Gs DXpeditions Invaluable for G3WGN new QTH search

G6GLP terrain

Take Off Angle Elevation angle in degrees = atanh (h/d) Height of obstruction (h) TOA Distance to obstruction (d) Elevation angle in degrees = atanh (h/d)

G6GLP to Middle East, VU, western VK 90⁰ azimuth Elevation of hill at 1.5km is 96m ASL Tony’s antenna is at 26m ASL The equivalent angle is 2.7⁰ [Compare: Haytor is 11km away at 284⁰ azimuth. A wave at 2.1⁰ will clear it.]

G6GLP to USA 300⁰ azimuth

Improving your station’s HF performance Raise antenna – what is the effect on TOAs that matter to me? Are there more distant terrain objects that may affect the signal path? If there are terrain features that may block the signal, in what directions do these lie? Do those directions matter to me? Does anything about the terrain suggest moving the antenna a short distance to improve take off? Can I move antenna closer to a downslope or away from an obstacle to optimise performance? Is the change in TOA significant?

Further Reading HFTA by N6BV: ARRL Antenna Book 21st-23rd Editions HFTA tools and add-ons: http://k6tu.net/?q=TerrainProfiles HeyWhatsThat: www.youtube.com/watch?v=g8_2biEttds HeyWhatsThat: www.vk3bq.com/2014/08/24/heywhatsthat-and-radio-mobile/

Questions?

Where to next? Zl7G 6Gs team that brought you TX6G and E6GG October 27- November 10 2016 Zl7G North Coast of Chatham Island www.6gs.org.uk

G3WGN New QTH Antenna at 10m