Tuesday, 23 January 2018

IBP beacon predictions for UK using ITURHFPROP

Over Christmas and the New Year I got better acquainted with the ITURHFPROP propagation prediction software.

This is the software that Gwyn G4FKH uses to produce the monthly HF predictions for RSGB’s RadCom magazine and which was produced by the ITU.

Gwyn adapted it to produce a graphical output, which can be found at www.predtest.uk

But I was intrigued to see if I could use it to produce some predictions for the worldwide International Beacon Project (IBP) chain that runs on 14, 18, 21, 24 and 28MHz. I won’t go into too many details here about the IBP network as you can find all you would want to know at http://www.ncdxf.org/beacon/

The good news is that as they all use the same power output (100W max.) and the same antenna (pretty much a unity gain or +2.15dBi antenna) it should be fairly easy to model what the expected signal strength should be here in the UK.

ITURHFPROP runs in Windows and uses an input file with all the parameters needed, such as your QTH lat. and long., the transmitter’s lat. and long., required SNR, bandwidth, smoothed sunspot number, power etc etc.

You then run it from the command line and it creates an output file.

I ended up creating input files for each of the beacons, and a spreadsheet that can take each of the output Field Strength (dB(1uV/m)) figures and convert them into S units.

I then created a batch file that runs all of the predictions for each of the beacons in one go. With an I5 processor this takes less than about 15 seconds.

The spreadsheet then formats these so that I can produce the chart you see on the page. This may sound long-winded, but it really doesn’t take long. I’m sure someone with Python programming skills could automate the whole thing, but I wanted to make sure it worked first before going any further.

The end result has proved to be quite accurate and shows that at this point in the sunspot cycle we can’t expect miracles in terms of hearing the distant beacons. While some are audible on 14 and 18MHz, generally we are not hearing much above that.

In the UK, what have been audible quite regularly this month on 14.100MHz are RR90 (Novosibirsk, Siberia), CS3B (Madeira), 4U1UN (New York) and occasionally 4X6TU (Tel Aviv).

It also shows what the effect of an elevated K index can be as this generally means the beacons are less audible (if there at all) as the MUF declines. We have been suffering from the adverse effects of coronal holes recently and that isn't going to end any time soon.

You can see the predicted MUF over different path lengths in near real-time using the graphed ionosonde data for the UK at http://www.convectiveweather.co.uk/ionosphere/graphs.php?type=live

This was produced by fellow RSGB Propagation Studies Committee member Jim G3YLA and his colleagues at Weatherquest in Norwich.

I’ve posted the predictions here to see if they are of interest to anyone. If they are I’ll update them monthly.

To view the January IBP prediction chart full size just click here.

Friday, 22 December 2017

Radio Caroline back on Medium Wave

The Orford Ness masts
If you fancy a bit of nostalgia you can now listen to Radio Caroline again on 648kHz AM on the medium wave.

The famous pirate radio station needs little introduction, but is now broadcasting legally using (ironically) the famous Orford Ness antenna system on the Suffolk cost, formerly used to transmit the BBC World Service in English around the clock on 648 kHz from September 1982 until March 2011.

The station was founded in 1964 to play pop music all day at a time where broadcasting was dominated by the BBC and pop was played for an hour a week.

Caroline was one of five stations granted a community radio licence by Ofcom and is now running 1kW, but with a really good antenna mounted right next to the sea.

The station is 59+20dB at my home QTH 10 miles south of Norwich (JO02NN) using a Perseus SDR and a homemade 1m active loop mounted in the loft. It is also easily heard with a portable radio.

Radio enthusiasts around Europe might like to listen for it.

More information:

Orford Ness transmitter:
https://en.wikipedia.org/wiki/Orfordness_transmitting_station

Radio Caroline:
http://www.radiocaroline.co.uk/



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Friday, 15 December 2017

Propagation prediction maps updated until June 2018

I have now updated my propagation maps with the latest predicted smoothed sunspot numbers for the period up until the end of June 2018.

You can access them using this link.

The sunspot numbers continue to fall as we head towards sunspot minimum sometime around 2019.

If you use the charts look for about 60-70% reliability for SSB (yellow or hotter) and perhaps 40-50% for CW or PSK (green). For FT8 you may be able to work stations where the reliability is down to 20-30% (blue).

Of course, these are a guide and if you want to try making charts for your own station I recommend the online software at either voacap.com or www.predtest.uk/


Tuesday, 21 November 2017

Christmas present ideas!

As Christmas is coming, I thought I would remind people that there are some great radio-related goodies for sale at CafePress.co.uk 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!

Or there are a number of my radio-related books that make good presents , including "Radio Propagation Explained", "Antenna Modelling", "Stealth Antennas" and "Getting Started in Amateur Radio". Use the image links on the right for more information.

Thursday, 12 October 2017

HF Propagation at Sunspot Minimum

The effects of coronal holes are likely to continue for a
couple of years.
This weekend I’ll be giving a talk at the RSGB conference on “HF Propagation at Sunspot Minimum.”

This will show that we can expect the minimum to be around late 2019 or 2020. It is hard to be precise, as the minimum is something you can define after the event, not before or during!

What I will say is that we can probably expect the effects of solar coronal holes to continue, at least until we are well into the minimum.

Geomagnetic storms can cause problems on HF, although they can also bring short-lived ionospheric enhancements so they are a double-edged sword.

For example, on Tuesday 10th October the bands were open to DX all the way up to 12 metres. But as the solar wind from the coronal hole hit on Wednesday, apart from a short-lived ionospheric enhancement the MUFs took a dive.

By Thursday (12th) lunchtime, 20m was struggling to fully open and 17m was showing very little activity indeed. But by Thursday afternoon, and with a K of 5,  I had worked Saudi Arabia on 10m SSB.

This shows that at sunspot minimum with a solar flux index of just 66, quiet geomagnetic conditions may be better than stormy ones. So look for a K index in three 0-2 range, not 5-7! But then again, when solar plasma first hits the earth we may get some short-lived enhancements right up to 10m, so a high initial K index can work for us.

For those who weren't at the lecture, I showed that monthly average maximum useable frequencies will decline with the sunspot number. This doesn't mean there won't be F2-layer openings on 21MHz and higher, just that they won't be as reliable or as long lasting.

Other than that I encourage people to play with a propagation program to get an idea of what might be possible.

My suggestions are:

Windows based

VOAProp

HAMcap

W6ELProp (when installing, right click and run as administrator on Windows 10)

VOACAP


Online

VOACAP.com

Predtest.uk


Other sources of info I mention are:

Solarham.com

NOAA – Space Weather Prediction Centre

Real-time F2 critical frequency display (this will soon move to Propquest.co.uk)

Smoothed Sunspot Numbers

Latest extreme UV image of the sun from the Solar Dynamics Observatory spacecraft (shows coronal holes)

Lastly, I talk about the difficulties of predicting openings with FT8. One suggestion is to use VOACAP and set the required SNR to a figure of -20dB or so. It is usually set to about 24-31dB for CW and 45 for SSB. This is still experimental (as some SNR figures are quoted as dB per Hz, while others are quoted in a 2500Hz bandwidth), so you might have to play with it. VOACAP’s settings are critical and it is worth reading the notes on the VOACAP website and also the “Top 10 mistakes in using VOACAP”.

Sunday, 24 September 2017

Visit to NI6BB, USS Iowa, San Pedro, California

The big guns of the USS Iowa.
As many regular readers of this blog may know, I try to visit as many special amateur radio stations as I can when working overseas.

This week I am in Long Beach, California again for a conference and it was an ideal opportunity to visit the famous battleship USS Iowa in nearby San Pedro, which has an amateur radio station with the callsign NI6BB.

USS Iowa (BB-61) is a floating maritime museum that is well worth the visit. It has a rich history that spreads from World War Two, through the Korean conflict in the 50s, and the cold war before it finally became a museum in 2012.

US Navy veteran Jerry Johnson with
one of the 110lb powder sacks.
Its main battery consisted of nine 16 in (406 mm) Mark 7 guns, which could fire 2,700 lb (1,200 kg) armour-piercing shells 23 miles (37 km). On the tour you find out how they used to load the guns with six 110lb silk sacks filled with powder, which when ignited with a single cartridge would rapidly burn in one third of a second, firing the 1,900 lb (862 kg) shell out at 2,690 feet per second (820 m/s).

The USS Iowa discone-cage HF antenna,
complete with plastic owl!
The other statistics are staggering (including 19.7-inch armour plating), but I’ll leave you to Google them.

Anyway, back to the radio, the radio room on the Iowa is well equipped with a Kenwood radio for HF.

On the bow of Iowa is the discone-cage antenna. Fed at the top it is a discone providing coverage from approximately 10 to 30 MHz with a VSWR below 3:1. The antenna has a plastic owl on it to stop pigeons resting - but they ignore it apparently!

Ron Frank N3HI let me operate some 20m SSB from the ship, as I have G0KYA/AB8ZV UK full and US Extra Class licences, and I worked a few stations including Washington State and Ohio. One was a “nearly” as I couldn’t quite get his full call before he faded away, which was a shame. HF conditions weren’t brilliant.

There were one or two loud stations on CW, which they often work, and Ron says they tend to operate a lot of digital too, including FT8.

Anyway, my thanks to Ron for letting me play for an hour and giving me some detailed history of the USS Iowa. If you are ever in the Long Beach/San Pedro area go and visit. It is truly fantastic.

My thanks to Ron Frank, N3HI.
I also revisited W6RO, "The Queen Mary", in Long Beach, California where I am staying. I operated from there in 2012 and they always welcome visiting radio amateurs. We had a long chat about UK and US amateur radio.

If you are interested in some of my other historic radio visits you can read about:
  • NI6IW - USS Midway, San Diego, California
  • W7SUB - the USS Blueback, Portland, Oregon
  • K6KPH - The Maritime Radio Historical Society, Point Reyes/Bolinas, California

Saturday, 9 September 2017

Elecraft K1 discontinued

Elecraft has announced that it has discontinued the K1 transceiver. I'm not surprised as this had been predicted some time back.

Component availability had been an issue, and technology has moved on.

Luckily, a local ham managed to get one of the last K1s after reading about them - and seeing this blog.

I'd like to thank Elecraft for producing a great little radio and for supporting QRP. There's always the KX2 and KX3!