Monday, 16 February 2015

Partial solar eclipse propagation experiment, March 20th 2015

The RSGB Propagation Studies Committee (PSC) is keen to encourage radio amateurs to take part in an experiment during the partial solar eclipse taking place on Friday 20th March 2015.

The path of totality will pass north of us, over the Faroe Islands, but the UK will experience up to 89% totality (depending upon where you live).

This is a great opportunity to try some simple experiments to see how the sun’s ultra violet output affects our ionosphere and how some radio waves are propagated.

On the morning of Friday March 20th 2015 the D layer above the UK may not be as strong due to the eclipse, and you may be able to hear stations on the lower bands – 1.8 MHz, 3.5 MHz and perhaps 7 MHz that would otherwise be inaudible during the day.

For example, if you listen for a medium wave radio station that is more than 250-300 miles away during the day you may not hear it – it is too far away for its ground wave signal to reach us, and any sky wave signal is absorbed by the D layer of the ionosphere.

But at night its sky wave signals are not absorbed as there is no D layer and they are free to be reflected back to earth from the higher E/F layers.

This is why you can hear distant medium wave stations on a radio at night, but they aren’t there during the day. You get a similar effect on Top Band, and to a lesser extent 80m/40m.

We are keen to encourage radio amateurs to conduct experiments during the eclipse, especially if they can use software defined radios (SDRs) to record the whole eclipse period for later analysis using Spectrum Lab or similar.

PSC has also devised a simple experiment for schools to undertake using portable medium wave radios. A PDF flyer about the eclipse propagation experiment is available to download here.

The information we gather will also be shared with the Rutherford Appleton Laboratory at Harwell.

The partial eclipse starts in the Midlands at about 08:25 GMT on Friday March 20th and ends at 10:41 GMT. Maximum eclipse will be at about 09:30 GMT.

Monday, 19 January 2015

Working the K1N Navassa DXpedition from the UK

The 2015 K1N DXpedition to Navassa Island in the Caribbean is due to kick off in the next couple of weeks.

Navassa is a United States island, just west of Haiti. It is rare because there hasn't been a DXpedition to Navassa in 22 years, and there is unlikely to be another for another 10!

At least one station will be on 20 meters 24 hours a day. 160M and 12M will be CW only and 10M will be SSB only.  Other bands will alternate CW and SSB.  At least one station will always be on RTTY, and they will operate RTTY on no more than three bands.

To find out more about the K1N DXpedition see

But what about working it from the UK?

Navassa is going to be a 4,600 mile sea path from the UK and propagation at this time of year favours this path off to the south-west. If you have a beam you need to turn it to 270 degrees from central UK.

So what band should you work them on and when?

160m (1.8 MHz)
You'll need a mutual dark path between you and Navassa. This will occur from around 23:00UTC to 07:25UTC, although the actual times will change as the DXpedition goes on. My money would be on a dawn or grey line enhancement here in the UK at or around sunrise, so look from about 07:15 onwards.

80m (3.5 MHz)
Its a similar story on 80m. Look from around 22:30 onwards, with the strongest possibility perhaps being in the early hours. Again, you may see a greyline enhancement around UK sunrise, or a little earlier, say 07:00hrs, which will also shut out a lot of Europeans making the job a little easier.

40m (7 MHz)
The time available to work K1N extends a little more on 40m, so you may see them a little earlier in the evening and they may still be there some time after UK sunrise, perhaps even up to 09:30-10:00hrs.

30m (10 MHz)
Signals may be there for all 24 hours, although they will get stronger from about 21:30-22:00hrs and remain so through the night. Signals will once again get weaker from mid morning.

20m (14 MHz)
Now we move up to the HF bands proper and a daylight path becomes a boon. You have a 75-100% chance of working them from 11:00-23:00 hrs, but the loudest signals may be around noon and from 20:30-22:30hrs. D layer absorption will make signals worse in the mid afternoon.This will be the most popular band so may be a struggle.

17m (18 MHz)
Similar story, with the band open potentially from noon UTC – 20:30hrs, with the best time around noon -2pm.

15m (21 MHz)
As we head northwards in terms of frequency the path opening gets a little shorter. Perhaps 12:30 – 20:00hrs with the best time in the mid to late afternoon.

12m (24 MHz) and 10m (28 MHz)
Again, a shorter slot. Look between 13:00 – 18:30 hrs on 12m, and from 13:30 – 17:30 hrs on 10m. Best times may be around 16:00hrs (10m) and 17:00 – 17:30hrs (12m).

If you had to pick a band for your "best chance" it looks like 15m (21 MHz), or perhaps even 17m (18 MHz). Twelve metres (24 MHz) may also be useful. You often stand a better chance on a WARC band like 18 MHz or 24 MHz as there are fewer hams with beams. 

Here is what it looks like graphically using WINCAP Wizard. it uses the "best" and "next best" bands for each hour.Click to see a bigger version:

And again using the VOACAP Online tool at
Go for the "hottest" spot in terms of the best band. Click to see a bigger version:

Monday, 5 January 2015

UK HF Propagation Prediction maps

I have now updated my UK HF coverage prediction maps for this quarter using the current smoothed sunspot numbers (SSNs). The maps for April to December can be used as being representative, but will be updated as and when the SSNs are updated later in the year.

On the current evidence it looks like we passed the peak of Sunspot Cycle 24 in the Spring of 2014. However, the cycle still seems to have some life left in it.

The peak solar flux index (SFI) for the cycle occurred on 23rd October 2014 with 227, although there were plenty of other times when it bettered 200, including January 2014, October and December 2014.

On an annual basis, 2014 had the highest average daily sunspot numbers of any year since 2002, according to the ARRL, although the peak solar flux indices were higher in 2002, hitting 261 on 29th January 2002.

The highest peak solar flux indices of cycle 23 were actually seen in 2001, with 283 being reached on 26th September 2001. This cycle has been poor in comparison.

But what next? What has been very apparent is the general increase in solar flares and coronal mass ejections (CMEs) recently. This has led to disturbed geomagnetic and HF conditions and is typical of the downward trail away from a sunspot maximum.

Over the next quarter we can expect to see overall sunspot numbers decline slightly, with solar flare and CME activity remaining high. Expect to see SFI numbers in the range 120-180, still good enough to provide good openings to DX on the higher bands at times.

We may see the cycle peak up yet again before it finally tails away, but are we likely to see the SFI go above 200 again? Who knows.

You can see my UK HF prediction maps at or use the link top right.

Saturday, 27 December 2014

A little post-Christmas HF QRP activity

Thought I would fire up my little three-band Steve Weber-designed MTR Mountain Topper radio for a bit of QRP fun this afternoon.

In a couple of hours I worked SP3JFK, 9A0QRP, OM5WW, HB9DAX and OK1DMP on 20m around the 14.060 MHz QRP calling frequency.

So that's Poland, Croatia, Slovakia, Switzerland and Czech Republic while running about 2.5W to a wire dipole at 25ft. More than happy with that!

What an amazing little radio.

On Monday 29th I thought I would give my Yaesu FT-817 an airing too with 5W CW and power from a small LiPo battery at about 11V.

Worked UR5AF, DK2BSN, S507PMC, KA5CJJ and EW7BW, adding Ukraine, Germany, Slovenia, USA (Texas) and Belarus to the total.

KA5CJJ was a tough one on 10m (all the others were 20m) as the band was closing. Allen was in Texas and running QRP too.

The FT-817 is another great little QRP radio.

Finished off the G-QRP Club Winter Sports on 31st December with my Icom IC-756 Pro 3 set at 5W with OF9X (Santa Claus SES in Finland), EA2BD/P (Ignacio in Spain), UT2QA (Peter in Ukraine) and TF3CW (Siggi in Iceland). Life's obviously not too short for QRP!

Wednesday, 19 November 2014

Christmas present ideas!

As Christmas is coming, I thought I would remind people that there are some great radio-related goodies for sale at and .com.

You can choose from a number of items, including:

  • Three different types of ship's radio room clock, with silent period sectors marked
  • "Remember QRT SP" Merchant Navy Radio Officer merchandise
  • "Keep Calm and Work Some DX" merchandise
  • "Keep Calm and Work Some CW" items
  • Nikola Tesla merchandise, featuring him sitting in his Colorado Springs laboratory in 1899, surrounded by electrical arcs.

You can have the last three slogans added to T-shirts, sweatshirts, mouse mats, calendar, mugs and much more.

Just go to the Radio Room!

Tuesday, 28 October 2014

European 6m Sporadic E (Es) study

CS5BLA as received at DK8NE - click for full size.
This summer I undertook a study into 6m Sporadic E (Es).

The mains reasons for this were:

1. To establish a database of Es contacts that anyone could use for research.
2. To evaluate claims that Es can be periodic – that is, good Es conditions may repeat themselves over a finite period.
3. To look more closely at so-called Short Path Summer Solstice (SSSP) propagation, when stations in Japan (JA) are regularly heard in Europe around the time of the summer solstice (June 21).

The first task was to find a way to create a database of contacts on 6m. The decision I took was to use the Reverse Beacon Network (RBN). This is a fully automated system that uses CW skimmers to look for, decode and report signals on the amateur bands.

The plan was to analyse 6m beacons received by the skimmers in Europe. This would take out any human element and also give 24-hour coverage as beacons operate continuously.

So each day from May 1 to September 30 I downloaded the daily RBN logs, and pulled them into Microsoft Excel. Once there I was able to use Excel's “Filter” command to leave just the 6m CW reports received in Europe. A final filter was applied to remove all contacts received in the same entity, for example DL to DL. This reduced the file sizes tremendously.

What were left were certainly not all Es contacts. Only by later inspection would it be possible to look for potential contacts in a typical Es range of 800–2,200 km (500 – 1375 miles).

What I ended up with were monthly Excel files, ranging from 13.9Mb in July 2014 to 1.5Mb in September. By opening them in Excel it was then possible to use the “Filter” command to look at specific paths.

Ultimately, I tried to combine all five months into a single Excel file for others to use, but with more than 162,000 entries or lines the file wouldn't save correctly.

The four paths examined - click for full size.
To look for any periodicity in Es openings four paths were selected as received by DK8NE located at JN59FW in mid Germany. This RBN skimmer was chosen as it was in use over the whole six-month test period. There were two days when it was offline due to an internet failure, but Uli was able to e-mail me the missing data.

The DK8NE 6m skimmer uses an M2 HoLoop at 45m AGL, which feeds two skimmers covering 50.000-50.190 MHz (Perseus SDR) and 50.300-50.490 MHz (SDR-IQ), both using a convertor.

I also looked at JA openings into EU on 6m.

The end result was that I ended up with a lot of data, which is being used for a feature for the RSGB's RadCom magazine.

But if you want to download the data and have a look yourself you can. Just choose one or more of the links below. Once you have the file in Excel or OpenOffice/LibreOffice Calc you can use the "Filter” command to select what you want to look at.

Downloadable Excel Files:

Monday, 22 September 2014

NI6IW, USS Midway, San Diego

I was lucky enough to visit the USS Midway aircraft carrier in San Diego, California, last week while on a work trip.

It is now a floating museum, dedicated to telling the story of how an aircraft carrier functioned, with a lot of the stories told by ex-Navy personnel who served on it.

I was even more lucky because Hal KI2HAL gave me a behind the scenes tour of the ship's amateur radio station NI6IW.

It has three Elecraft K3s that allow it to work all bands. Because of the museum's rules, all the antennas have to be the original authentic models fitted to the ship when it was in service. This means that the ham station uses a couple of navy verticals and a sloping three-wire set-up.

I was able to tune one of the verticals for 17m to see if I could work the UK – a distance of more than 5,000 miles. I didn't make contact, although I think I did hear G3SGE on CW working a CT station. I've not been able to track down who G3SGE is though.

The ship also has an Icom D-star set-up and makes a lot of contacts that way.

The ship is active on the Museum Ships weekend "on the air" days so you might be lucky to hear it.

The antennas
In all, the ship is fascinating – you can hear from a retired Navy pilot exactly how you land and take off on an aircraft carrier. Hairy stuff.

My thanks to Hal for showing me around. Just click on an image above to see a bigger one.