1. Propagation to 3Y0X Reality v Predictions
Steve Nichols G0KYA, RSGB Propagation Studies Committee
This was the title of a talk given by Steve Nichols G0KYA to the RSGB HF Convention on Saturday 8th October 2006.

2. You can see here just how close to Antarctica the Dxpedition was.

3. Just a few images to give a feel for the conditions under which these operators worked. More can be found on the official website at

4. A few definitions:
Solar Flux: A measure of the electromagnetic output from the sun, measured at a wavelength of 10.7cm (2800MHz).
Sunspot Number: The number of observed sunspots and sunspot groups.
A index: A daily average measure of the distortion of the earth’s magnetic field due to ions from the sun (flare material, CMEs, coronal holes etc).
K Index: A three-hourly (logarithmic) measure of the distortion of the earth’s magnetic field due to ions from the sun (flare material, coronal holes etc).
These were given in the presentation to help define some of the terms that were used.

5. Good: Bad: High solar flux (perhaps 150 – 200+) and low A/K indices
Perhaps A less than 10
Bad:
Low solar flux (less than 80) and high A/K indices
Perhaps A more than 25

6. What about solar activity?
The solar flux and sunspot numbers for the period of the operation. Note there isn’t total correlation.
Source: NOAA, Space Environment Center Predicted Smoothed SSN = 18.4

7. What about geomagnetic activity?
A and K indices for the period
Source: NOAA, Space Environment Center, Middle Latitude - Fredericksburg

8. One problem was the proximity of both the long and short path to the auroral ovals as this grab from W6ELProp shows. This could have been a big problem if the A and K indices had climbed higher, especially on the long path.

9. The three prediction programs:
HamCap – as used on the 3Y0X web site. Uses the VOACAP engine (free)
W6ELProp – the classic simple program from Sheldon Shallon (free)
ACE-HF – a more sophisticated program using the VOACAP engine ($99)

10. A typical grab from HamCap, which uses the VOACap engine

11. HamCap
And the same again, this time using false colours to make the conditions clearer. This show the 20m short path between G and 3YOX at 21:00Z.

12. 20m 24-hour propagation (short path)
HamCap
20m 24-hour propagation (short path)
In the original Powerpoint presentation this was a 24hour animation of propagation on 20m shortpath.

13. HamCap
And an alternative view of propagation in HamCap. The yellow boxes indicate the optimum times. The red line is the MUF. The vertical white line is the current time.

14. HamCap
And long path – note that nearly all long path predictions were around the same time.

15. W6ELProp is a little bit more clunky, but perfectly usable
W6ELProp is a little bit more clunky, but perfectly usable. It uses the Raymond Fricker model rather than VOACap, but proves very reliable. Here you can see a number of bands and the predicted availabilities (probabilities)

16. And the same for longpath – only showing 20m and 17m as possibles

17. ACE-HF – Short-path, 80m,40m,30m
400W
+ three-element Yagi at both ends
ACE-HF uses the VOACAP engine. Here are the predictions for 80m, 40m and 30m. As you can see it predicts no 80m opening – contrast this with W6ELProp which does. The colour code green is for more than 50% reliability.

18. ACE-HF – Short-path, 20m,17m,15m
400W
+ three-element Yagi at both ends
And the same for 20m, 17 and 15m shortpath.

19. ACE-HF – Long-path, best cases
400W
+ three-element Yagi at both ends
These were the best case scenarios for 30m, 20 and 17m longpath. As you can see 20m was the best bet.

20. So what could we conclude for 160-40m?
Both HamCap and ACE-HF say that 160m and 80m are total no-go areas, but W6ELProp says 80m possible
W6ELProp/ACE-HF say 40/30m may be possible – ACE HF says 30m is better All programs agree that you need a VERY decent antenna and power – QRPers need not apply!

21. So what could we conclude for 20-10m?
All programs agree that you need a VERY decent station – eg 400w and a tribander at 85 feet
Conditions are marginal at best, although best bands are: m short path 0200–0400, and
17m short path hrs
15m short path hrs m probability less than 20% (get used to white noise) m – wash the car/wait six years!

22. So what about 80m and 160? Let’s make some intelligent (?) assumptions
You need a dark (night) path between the stations 
You need a low A and K Index 
Possibly low sunspot numbers? 
There good be greyline enhancement at UK sunrise 
Looking at mutual sunrise/sunset times then this
only gives:
02:45hrs - 07:25hrs

23. With a big but!
The sun is never more than two degrees below the horizon at 3Y0X.
So, best “greyline” time from UK is therefore: 06:40hrs – 07:25hrs
Actually, six minutes later at the beginning (07:28hrs), and 13 minutes earlier at the end (07:09hrs) – but calculate according to YOUR longitude.

24. The reality - 3Y0X to G
These are the official figures from 3Y0X on the number of UK stations worked per band. The fact there were any contacts on 12m is a miracle. Note around 140 contacts were made on 80m/160m, despite ACE-HF’s dire prediction

25. Top band/80m reality
Theory says contacts possible between 02:45hrs - 07:25hrs
Best “greyline” time is 06:40hrs – 07:25hrs
160m
G3BJ :27hrs
G3KZR :38hrs 
G3XTT :09hrs 
G3SED :10hrs 
80m
G3BJ :34hrs  (ish) :23hrs :50hrs 
G3SED   07:16hrs 
G0TSM :25hrs 
:12hrs 
:43hrs 
My theory on top band and 80m v reality of those CDXC members who did make the contact. Note the large number of greyline contacts (ticked).

26. Top band - contacts v sunrise
And again, showing the mutual darkness time v contacts, plus the greyline contacts. Sunrise was obviously the best time.

27. Top band - contacts v K index
Top band station was dismantled in preparation for departure.
Was there any connection between the number of Top band contacts v low K index? Not really. The best days were obviously when the K index was low, but there isn’t enough data to confirm it and other factors might have come into play.

28. Top band - contacts v sunspots
Top band station was dismantled in preparation for departure.
What about sunspot number? The figures go some way to suggesting that the better conditions were on days with low sunspot counts. But it isn’t conclusive. Better to say that low sunspot numbers and low K index are better for Top Band propagation, but it isn’t clear cut.

29. 80m contacts v sunrise
80m contacts v the night period and sunrise. Once again, greyline rules and this compares favourably with the W6ELProp prediction.

30. 80m reality (W6ELProp) G3BJ 07:34 (sunrise 07:25)
W6ELProp v reality for 80. Note that sunrise was favoured time for contacts. The green line shows sunrise at my QTH in Norwich, the blue line is west of me at G0TSM and G3BJ’s locations. Again, sunrise +/- 15 mins. is optimum.

31. 80m contacts v K Index
80m v K indices – not much correlation.

32. 80m - contacts v sunspot No.
This suggests that 80m contacts were more prevalent on days with low sunspot numbers and vice versa.

33. 80m v 160m – any correlation by day?
Top band station was dismantled in preparation for departure.
Was there any correlation between 160m being open when 80m was? On the face of it no, although the 13th was a good day for both.

34. 80m v 160m - any correlation by time?
Looks like good correlation to me.

35. 40m reality v ACE-HF
40m Ace-HF prediction v reality. This was a good prediction. Note the greyline upsurge, or was it just because there were more people trying at that time?

36. 40m reality v W6ELProp
Again, W6ELProp did a good job.

37. 30m/40m reality (ACE-HF)
Some known contacts plotted on the prediction curves – good correlation.

38. 20m reality v ACE-HF (3el Yagi)
Again, good correlation – the bottom graph is long path.

39. 20m reality v W6ELProp
Good correlation on W6ELProp – note the large number of contacts around Z which are probably long-path (the lower prediction) plot.

40. 17m reality (ACE-HF)
Great prediction here from ACE-HF – a few contacts appear a little too early, but are probably long-path.

41. 15m reality (ACE-HF + W6ELProp)
Another good correlation – was that lone contact at 2300Z a mistake???

42. 15m/17m/20m reality (ACE-HF)
Some known contacts on the prediction plots – good correlation.

43. 12m reality (ACE-HF Yagi x 3el)
Note: W6ELProp predicts no opening!
ACE-HF was spot on – W6ELProp said it wasn’t possible. It did start to become possible in W6ELProp if you assume a flux above 100.

44. 12m reality (ACE-HF Yagi x 3el)
So much for theory!
So 12m opening came on a day with zero sunspot number, but after four days of SN>10

45. HF contacts v solar indices
The flux barely changed during the DXpedition.This graph rather suggests that contacts were more likely on days with low sunspot numbers but there could have been other reasons. I thought that perhaps the 13-15th were the weekend, but in fact the Saturday and Sunday were the 11th and 12th.
Notes: HF is 20-10m
Solar data source: NOAA, Space Environment Center.

46. Stop Press: VOAProp
VOAProp is a fairly recent innovation by G4ILO. It uses the VOACAP engine to produce user-friendly predictions, a bit like HamCap. It is free so give it a try.

47. Conclusions [1] – MF propagation
On 160m and 80m the maximum number of contacts occurred at the time of lowest (zero) sunspot number/low K index.
Sunrise/pre-sunrise at the UK end provided the best opportunity for contacts on 160m, 80m and 40m.
A calculation of “best greyline” time for 80m would have proved very fruitful!

48. Conclusions [2] – HF propagation
HF contacts appeared to be mainly short path, but there was a significant number of long path contacts on 20m in the afternoon (13th/14th).
17m, 15m, and 12m were textbook, following the predictions very closely indeed.
The best conditions appeared to be at times of zero sunspot number – this was when the big 12m opening occurred (12th) and when the 20m long path openings occurred (13th/14th).

49. Conclusions - software
Both HamCap (free) and ACE-HF ($99) did a pretty good job of calculating the HF possibilities, but did not predict Top Band/80m openings.
If using either, assume 400w and a Yagi to get a decent prediction.
W6ELProp also did a good job, but also highlighted the 80m openings – and its free!
My thanks to the 3Y0X team for a great Dxpedition and for making me lose some sleep!

50. Useful web sites This presentation – www.qsl.net/g0kya
HamCap -
ACE-HF - home.att.net/~acehf/
W6ELProp -
Geoclock - home.att.net/~geoclock/
VOAProp –