Steve Nichols, G0KYA

G0KYA's HF Propagation Prediction Report,
November 2010

Conditions have continued to improve as Solar Cycle 24 progresses.
We had a solar flux high of 91 over the last month and a low of 74.
On the whole, the flux is remaining above 80 which is an improvement. Geomagnetic conditions were unsettled at times, with high K indices on a number of days.

The HF bands were a mixed bag. At times great DX could be worked, especially on 21MHz. Absorption is less as you go higher in frequency which is why 21 and 28MHz can be so good. Talking of 28MHz, there have been days when DX is easy to work - South and Central Africa were all logged here on the first day of the CQWW contest (Saturday 30th October), whereas things were much quieter on the second day.

The US has been logged on 28MHz too at times, but we need higher solar flux numbers for these paths to be more regular and reliable.

For Short Path propagation predictions from the UK see my HamCap charts (based on 100W to a dipole at 35ft and a smoothed sunspot number of 31).

If the cycle continues to progress we should see flux numbers in the 90s before too long - the upturn is well overdue! Don't forget to check the bands during the CQWW CW contest on 27/28 November - if Morse is your thing this is a great opportunity to log plentry of countries. In CQWW SSB I managed to work HC8A (Galapagos Islands) on 21MHz with 100W to a 65ft inverted L so you never know what you might work.

Here are the predictions for November for all the bands:

General propagation, band by band

We are now entering the beginning of the winter period (propagation wise) when the low bands (160m, 80m and 40m) come into their own. The last two winters have seen great low-band propagation, with stations in the USA and Caribbean being worked on 80m well after sunrise. Generally, winter is a good time for East-West paths on HF too.

On 160m (1.8MHz or Top Band), solar absorption will prevent skip during the daylight hours. You should be able to work other UK stations out to about 50-80 miles via ground wave. The band will open around sunset and openings up to around 1,300 miles should be possible, with frequent openings up 2,300 miles. DX openings to the east from the UK should be possible around midnight and to the west before sunrise for well-equipped stations. DX conditions will improve as we head towards the end of the month. There may well be peaks at sunrise (greyline).

On 80m (3.5MHz), expect a similar pattern to Top Band with DX openings at night with peaks at midnight and around sunrise (greyline openings). Openings around the UK and out to around 500 miles should be possible during the day and between 750-2,300 miles at night. A low, horizontal antenna will be useful for relatively local, NVIS (Near Vertical Incidence Skywave) signals, but lower angle radiation, such as obtained with a vertical, will be required for DX.

40m (7MHz) is also another great DX band at this time of year. Forty metres should open to DX is an easterly direction during the late afternoon and towards the south at sunset. Relatively local contacts should be possible during the day, although low critical frequencies will mean that it is difficult to work other UK stations while perfectly possible to talk to European stations.

20m (14MHz) is likely to provide great DX openings during the hours of daylight. Peak conditions will be a couple of hours after sunrise for paths to the east and a couple of hours before sunset for paths to the west. Contacts up to 2,300 miles should be possible during daylight hours, but the band is likely to close to DX an hour or so after sunset. Occasional DX openings towards South America may be possible after nightfall.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, although 15m may struggle to open at all on some days if the flux remains low. The period from noon to late afternoon may be best, but both bands are likely to close at sunset and remain closed until some time after sunrise the following day. 21MHz may offer the best opportunity for DX at the moment on HF.

12m/10m (24MHz/28MHz) may be good or bad depending on the solar flux number. If the flux stays in the 70s-low 80s there may be many days where there are no signals at all, although occasional brief openings to DX may be possible. If the solar flux heads towards the high 80s or more than 90 then good DX should be possible during daylight. The best way to use 10m is call CQ - otherwise everyone just listens - or listen out for the many beacons. For a list see http://www.keele.ac.uk/depts/por/28.htm

You can find HF short-path propagation prediction charts from the UK at: http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's monthly HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/

Steve G0KYA
RSGB Propagation Studies Committee

• All propagation reports can be found at:
http://www.southgatearc.org/propagation