Propagation to 3Y0X Reality v Predictions

Steve Nichols G0KYA, RSGB Propagation Studies Committee

Propagation to 3Y0XPropagation to 3Y0XReality v Predictions Reality v Predictions

Steve Nichols G0KYA, Steve Nichols G0KYA, RSGB Propagation Studies CommitteeRSGB Propagation Studies Committee

www.qsl.net/g0kyawww.qsl.net/g0kya




A few definitions:

Solar Flux: A measure of the electromagnetic output from thesun, 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 magneticfield due to ions from the sun (flare material, CMEs, coronal holes etc).

K Index: A three-hourly (logarithmic) measure of the distortion of theearth’s magnetic field due to ions from the sun (flare material, coronal holes etc).


Good:High solar flux (perhaps 150 – 200+) and low A/K indicesPerhaps A less than 10

Bad:Low solar flux (less than 80) and high A/K indicesPerhaps A more than 25


0

10

20

30

40

50

60

70

80

08/02/2006 15/02/2006

Solar Flux

Sunspot Number

What about solar activity?

Source: NOAA, Space Environment Center. Predicted Smoothed SSN = 18.4


What about geomagnetic activity?

Source: NOAA, Space Environment Center, Middle Latitude - Fredericksburg

0

1

2

3

4

5

6

7

8

A Index

K Index



The three prediction programs:

HamCap – as used on the 3Y0X web site. Uses the VOACAP engine (free)

W6ELProp – the classic simple program fromSheldon Shallon (free)

ACE-HF – a more sophisticated program using the VOACAP engine ($99)



HamCap


HamCap

20m 24-hour propagation (short path)


HamCap


HamCap




ACE-HF – Short-path, 80m,40m,30m

400W+ three-element Yagi at both ends


ACE-HF – Short-path, 20m,17m,15m



ACE-HF – Long-path, best cases



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!


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: 20m short path 0200–0400, 0700-1000 and 1930-2200 17m short path 1300-2000hrs 15m short path 1700-1930hrs

12m probability less than 20% (get used to white noise) 10m – wash the car/wait six years!


So what about 80m and 160?

Let’s make some intelligent (?) assumptions

1. You need a dark (night) path between the stations 2. You need a low A and K Index 3. Possibly low sunspot numbers? 4. There good be greyline enhancement at UK sunrise

Looking at mutual sunrise/sunset times then thisonly gives: 02:45hrs - 07:25hrs


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.


The reality - 3Y0X to G


• Theory says contacts possible between 02:45hrs - 07:25hrs • Best “greyline” time is 06:40hrs – 07:25hrs

160m• G3BJ 13.2.06 05:27hrs• G3KZR 15.2.06 06:38hrs • G3XTT 13.2.06 07:09hrs • G3SED 13.2.06 07:10hrs

80m• G3BJ 15.2.06 07:34hrs (ish)

11.2.06 06:23hrs13.2.06 06:50hrs

• G3SED 12.2.06 07:16hrs • G0TSM 15.2.06 07:25hrs

17.2.06 07:12hrs 19.2.06 06:43hrs

Top band/80m reality


Top band - contacts v sunrise


Top band - contacts v K index

Top band stationwas dismantled in preparation fordeparture.


Top band - contacts v sunspots



80m contacts v sunrise


80m reality (W6ELProp)

G3BJ 07:34 (sunrise 07:25)


80m contacts v K Index


80m - contacts v sunspot No.


80m v 160m – any correlationby day?



80m v 160m -any correlation by time?


40m reality v ACE-HF


40m reality v W6ELProp


30m/40m reality (ACE-HF)


20m reality v ACE-HF (3el Yagi)


20m reality v W6ELProp


17m reality (ACE-HF)


15m reality (ACE-HF + W6ELProp)


15m/17m/20m reality (ACE-HF)


12m reality (ACE-HF Yagi x 3el)

Note: W6ELProp predicts no opening!


12m reality (ACE-HF Yagi x 3el)

So 12m opening came on a day with zero sunspot number, but after four days of SN>10


HF contacts v solar indices

Notes: HF is 20-10mSolar data source: NOAA, Space Environment Center.


Stop Press: VOAProp


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!


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).


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 decentprediction.

• W6ELProp also did a good job, but also highlighted the 80m openings – and its free!

• My thanks to the 3Y0X team for a great Dxpeditionand for making me lose some sleep!


Useful web sites

• This presentation – www.qsl.net/g0kya

• HamCap - www.dxatlas.com/HamCap

• ACE-HF - home.att.net/~acehf/

• W6ELProp - www.qsl.net/w6elprop/

• Geoclock - home.att.net/~geoclock/

• VOAProp – www.g4ilo.com

Documents

Propagation to 3Y0X Reality v Predictions