NDB Bristol

The non Directional Beacon (NDB) for Bristol in the UK is to be found on 414kHz and sends the morse code identifier 'BRI'.

It is not far away from the QTH here in Birmingham, UK being a hundred miles distant so the trace, as you can see from the image above, is good and strong.

The NDB is located within the area of the airfield itself and, more precisely, would seem to be located somewhere it the area shown in the picture taken from Google Maps. This complex is in an area just off the start of the main runway. The image from Google appears to be a newer image than the one on the Microsoft Live Maps page.

As far as I could find there are no photos on the internet of this beacon, probably because it is not easily accessible within the airfield perimeter and near to the main runway but if anyone knows of an image or knows the precise location please let me know.

Propagation Friday

Friday is propagation day but, I'm afraid, there isn't a great deal of propagation to report today!

The sun has been blank all week as we are deep into solar minimum and things are unlikely to get any better, at least for the next month or so.

However, as I write this, there is a faint glimmer of hope. A sunspot may be forming at a fairly high latitude and, if a spot does appear, then it will almost certainly be from the new cycle 24. It is not before time for us to see a sunspot as the sun has been blank much more often than it has been not. Appreciating that this is solar minimum, the sun appears to be far less active than I can ever remember it.

The end result of all this is poor HF propagation and very poor short wave beacon DX although the NDBs seem to come through regardless. In fact, solar minimum is a time when conditions on lower frequencies are often better.

There was some geomagnetic activity from a coronal hole pushing the solar wind to almost 500 km/sec but the magnetic field was not too disturbed.

It was also a poor week for VHF propagation with no sporadic E and no real meteor activity. In the UK we have had high pressure all week with the barometer starting around 1030 but now falling below 1000 as low pressure takes charge.

Other news
In other news - as they say - an asteroid called 2009 FD is making a close approach today a mere 620,000 km away and will be at its closest at around 1535 UTC so maybe it's time to hold your breath! In fact, it's a fair sized chunk of space rock and would make a nice dent if it hit so, if it changes course and destroys the Earth, please post a comment below to let me know!

Late Update
Just as I'm about to post this I checked on SpaceWeather and the sunspot didn't materialize and so the sun is blank yet again today!

Looking Forward To Some Sporadic E

It's the end of March 2009 now and very little is happening on the VHF front but soon that will all change when the sporadic E season arrives.

Probably, and that's the whole point of sporadic E because you never know when it will happen, the first openings will arrive some time next month, hopefully around the middle of April.

If you don't know, sporadic E happens when vhf signals bounce off small patches of ionised air in the atmosphere and can then travel between 1 and 2 thousand kilometres or sometimes more in one big hop. This means that transmitters miles away can suddenly appear on our receiver tuning dial. It can happen anytime, there is no way (yet) to predict it and this is half the fascination.

And, when it does occur, it can last for quite some time and produce unexpected signals from a wide area which, just as quickly as they came, can suddenly disappear.

The season lasts until around August with the best time at the end of May until my birthday on June 16th! Frequencies affected usually include the 10 metre and 6 metre amateur bands as well as Band II (the FM broadcast band) and, of course, all the frequencies in between. It is this phenomenon that gives rise to long distance television reception (DX TV), too.

So, it's time to brush off the old Icom, tweak the computer settings, load up the spectrum analyser and get ready. I want to try my hand at FM DXing this year, too, and also look on the old OIRT frequencies. These are used by many of the Eastern bloc countries and, if you are interested, a search for OIRT will reveal all the information and a list of frequencies although a future post will have more information.

Remember to click the image above to expand it to full size.

An Amateur Radio Beacon At 5mHz

Listening to beacons is both fun and a good way to check the propagation conditions for a particular band or range of frequencies.

GB3RAL
If you live in Europe, a good place to start is with the GB3RAL beacons. These are not one but three similar beacons all transmitting on the same frequency of 5.290MHz.

The experiment began around five years ago and the beacons are GB3RAL, located in Oxfordshire, England, another, GB3WES in the Northern county of Cumbria, England and the third, GB3ORK, in the Orkney Islands off the coast of North Scotland.

Each of them is a very low power beacon, running some 10 watts and all use simple dipole aerials.

However, they don't all transmit at the same time and they don't transmit continuously so if you tune in to the frequency above and don't hear anything: don't panic!

They transmit in sequence, one after the other at certain times past each hour and a visit to the main website, the url is given below, will show you when you can expect to hear them.

The heading photo shows the spectrum analyser trace of the beacons transmitting on the hour. The url to find out more about these interesting beacons is:

http://www.rsgb-spectrumforum.org.uk/5mhz%20beacons.htm

and also here for the logging information:

http://www.rsgb.org/spectrumforum/hf/5mhzbeacons.php

Some interesting information on manual and autologging the beacons can be found here:

http://g4irx.nowindows.net/fivemegs/beacon.php

And again at the RSGB website here:

http://www.rsgb-spectrumforum.org.uk/5mhz%20beacons.htm

Finally, GB3RAL is licensed to operate on 40.050 and 60.050 MHz in the low VHF area. I have not looked at it on these frequencies but have now made a note to do so.

Non Directional Beacons

Non-Directional and similar beacons dot the coast and interior of most countries. They are low power transmitters that normally simply transmit a callsign or a set of similar digital information to allow either aircraft or shipping to use them for navigation.

The fact that they are fixed both in position, frequency and power makes them ideal to use to help our understanding of propagation.

To receive these beacons you don't need any fantastically expensive equipment but you do need a receiver that will cover the medium and, for Europe at least, the long wave bands continuously since the beacons transmit in a range outside of the normal broadcast frequencies.

ideally, you need a receiver that tunes from 150kHz up in frequency into the 500kHz region. Most general coverage communication receivers will have this frequency range and many portable and relatively inexpensive sets will have, too. In addition, for those with an interest in integrating their radio hobby with one of computing, there are several radios that connect to or exist inside a computer.

Most of the screenshots that you will see here show my receiver that I use for SWL work which is a Winradio G303i. It is a PCI card that fits inside the computer (it's an AMD Athlon 3800 with 3 GB of RAM) and which uses a 70 foot long wire bent into an 'L' shape at only about 15 foot.

NDB Westcott

The top picture is the spectrum trace taken from the excellent Speclab program written by DL7YHF. If you need this program, the info about it and the download can be found at this link:

http://freenet-homepage.de/dl4yhf/spectra1.html

I have modified the program so that the trace runs horizontally but this is only because it fits the screen better than scrolling downwards.

The Westcott NDB beacon is on 355kHz and sends the morse code signature 'WCO'. It is well documented at the excellent aerobeacons site and also at the trevord site, the links are:

http://www.aerobeacons.nl/index-e.html

http://www.trevord.com/navaids/wco.htm

I caught the beacon at 19.03 on the 20th March 2009 and, as you can see by the trace, it was a good strong signal as it should be from Birmingham in the UK where it is only around 60 miles away. The receiver is a Winradio G303 and the antenna a 70 foot long wire at around 15 foot.

One of the nice things about NDB listening is that you can also usually find the location of the beacon and then pin-point it on an online map. The second image is just such a picture from Microsoft Live Map. The airfield and the beacon should be at the top right.

I checked the signal at 21.00z on Sunday 22 March 2009 before posting this and, if anything, the signal seemed stronger although the frequency was a lot noisier.