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

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

3. 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

4. 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

5. 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?

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

7. 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)

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

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

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

11. 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
( = 44.2%)
Extracted from ARRL Antenna Book 23rd Edition CD-ROM

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

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

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

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

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

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

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

19. What is the effect of local terrain?

20. 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?

22. 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

25. G6GLP terrain

26. 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)

27. 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.]

28. G6GLP to USA
300⁰ azimuth

29. 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?

30. Further Reading HFTA by N6BV: ARRL Antenna Book 21st-23rd Editions
HFTA tools and add-ons:
HeyWhatsThat:
HeyWhatsThat:

31. Questions?

32. Where to next? Zl7G 6Gs team that brought you TX6G and E6GG
October 27- November
Zl7G
North Coast of Chatham Island

33. G3WGN New QTH
Antenna at 10m