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Scanning Scene Returns


In his inaugural column, Tim Kirby, our new regular Scanning Scene expert, looks at how he got into the scanning part of the hobby


In his inaugural column, Tim Kirby, our new regular Scanning Scene expert, looks at how he got into the scanning part of the hobby, covers ADS-B reception and surveys signals from Earth, Air and Space.



It’s a great pleasure to find myself writing this column. Before I introduce myself, I would first like to pay tribute to Bill Robertson, otherwise known as Chris Lorek, the previous incumbent of this column. I can’t say I had the pleasure of knowing Chris well, although we had corresponded a few times recently.

For some years, I had admired him as someone with huge knowledge of radio in its widest sense. Chris’ death was untimely and a great shock to everyone who knew him. Radio enthusiasts will miss his ideas and writing.

I am sure that all readers will join me in offering our sympathy to Chris’ partner, Helen and to his family.


A Personal Scanning History

So, who’s your new columnist? My interest in scanning goes back to when I was 16 or 17. I enjoyed listening on the short wave bands but discovered that my VHF FM receiver could receive aircraft, if I tuned to around 104-106MHz, due to an IF image! This was not terribly reliable, so I saved my pocket money and bought a Realistic (Tandy) Jetstream receiver. Despite being a pocket-sized receiver, this was great fun and I delighted in receiving aircraft passing over the west country on their way to North America.

By virtue of yet another IF image (this time on the Jetstream receiver) I discovered that a radio amateur was living three doors away from me and operating on the 2m band. That new friendship started a process, which ended up in my taking the radio amateur examination – and I’m still in touch with that amateur on the air, almost 40 years later! My fascination with scanning continued after getting my amateur radio licence.

I purchased my first desktop scanner, another Realistic model, the PRO-2003. As well as the aircraft band, I used this to listen to radio amateurs on the 433MHz band in the town of Cheltenham, where I lived at the time, along with other services such as the Police, Fire Brigade and so on.

The PRO-2003 was a nice scanner, but my head was turned when the Yaesu FRG-9600 came out. Ray Withers, who ran a radio business in the Midlands, added a modification to the receiver, which allowed it to receive below 60MHz. I had a shortwave receiver, but I was interested in using the receiver in the low VHF bands as well as on the more usual VHF/UHF frequencies.

The FRG-9600 was a great receiver and a piece of equipment that I regret selling! I particularly remember using it for listening to paging transmitters from the USA on 35 and 43MHz as well as to wideband FM from Eastern Europe around 66-74MHz, during the summer sporadic-E season.

Still living in Cheltenham, I put a discone antenna up in my loft and discovered that I could hear some marine traffic. There were occasional transmissions from Swansea Coastguard, as it was then, which I could hear, courtesy of a transmitter on the first Severn Bridge as well as traffic on the Gloucester and Sharpness Canal on 156.725MHz (a channel I still listen to, when I am in the area).


Air and Space

The FRG-9600 was also my first introduction to listening to signals from space, and I found that I was able to hear data from the Russian Cosmos satellites passing overhead.

It was around this time that I discovered ACARS transmissions from aircraft. I bought a dongle from Lowe Electronics, who were marketing them at the time, and I connected this in between my scanner and computer.

Although it seems primitive now, it was interesting to see the received messages; it was especially exciting when position reports were received, and you could see where aircraft were located.

Nowadays, if you want to try ACARS decoding, you can use an RTL-SDR dongle and a Raspberry Pi!

Following the advent of amateur radio equipment with wider coverage, I moved away from dedicated scanners for my VHF/UHF listening. In retrospect, I think this was a mistake as there is nothing like a dedicated scanner. However, you live and learn. More recently I became interested in decoding ADS-B transmissions from aircraft. My first ADS-B receiver was one from Bulgaria. Have a look at this URL:

It worked very well. Subsequently, I enjoyed using RTL-SDR dongles and a Raspberry Pi to decode ADS-B. This too worked very well indeed, and at minimum cost. I fed ADS-B data into the various flight tracking networks and found this fascinating, especially with RAF Brize Norton and Fairford so close at hand.

I also used the Planeplotter software to decode ADS-B messages (Fig. 1).

One of the more interesting ADS-B catches was Air Force 1, when President Obama visited the UK. I picked up the aircraft crossing the River Severn on the homeward-bound flight.

I suspect we will come back to ADS-B in future columns. If you’ve not tried it, do give it a go! The coverage you can get with a very simple aerial is impressive. From here in Oxfordshire, with a 1090MHz antenna in an upstairs window, I can regularly see aircraft out over the English Channel to the south.

My friend Dave Robinson, based high up in Malvern, Worcestershire, and with also working a loft-mounted antenna, can see aircraft all over the country and out across the North Sea.


Air to Sea

In a similar vein, I enjoyed learning about AIS transmissions from ships. However, sadly, my current location away from the coast means that I have to use web-based tracking such as and have not yet set up my own AIS receiving post. However, I hope to do that in the future.

Working close to the Pool of London, where various cruise ships visit on a regular basis, it is always interesting to look at AIS to follow the progress of ships in and out of port.

I do have some dedicated scanners again. They are two Uniden Bearcat scanners, picked up locally for next to nothing as a result of a small ad on Facebook!


A Shift to SDR

Software defined receivers are a real boon for monitors because the panoramic display of the spectrum allows monitors to find new and interesting signals with ease.

My first SDR receiver, after playing with the RTL-SDR devices, was a Funcube Dongle Pro Plus; more recently, I have enjoyed using the SDRPlay RSP devices.

In the beginning, I made use of the SDR# software. However, at present, I am working with the SDRuno software and an RSPPro receiver on my PC.

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The Cubic SDR software allows me to use the RSPPro on my Mac.

I always have an RTL-SDR dongle in my rucksack and I can use G-QRX on the MacBook Air – also in my backpack – so there are lots of options for listening at short notice, as well as extended coverage on my VHF/UHF handhelds normally used for amateur radio. The latter double nicely as marine band monitors when I am in London or close to the coast.

SDR software provides a myriad of opportunities for decoding signals as well as ‘just’ listening. Armed with a virtual audio cable and DSDPlus, I could decode DMR and other digital voice signals, long before I ever had any dedicated digital radio hardware.

I hope that the previous paragraphs have given you some idea of my background and the sorts of things that I have enjoyed listening to over the years.


Signals from Space

I think nothing quite captures the imagination quite as well as trying to receive signals from space. If you’re reading this and thinking ‘my aerial is rubbish, I could never do that’, please keep reading, because, in fact, you can!

Although some signals are very weak, others are very strong indeed, and you will be able to receive them on a handheld scanner with just a rubber duck aerial!

Some of the strongest signals come from the International Space Station (ISS). In this context, a first frequency to keep an eye on is 143.625MHz FM. Of course, you are only likely to hear anything when the ISS is above the horizon at your location. There are numerous ways to find out when the ISS passes are – there are many applications for smartphones, or you can use the great Heavens Above website:

If you keep an ear on this frequency, you may well hear signals come up when the space station comes within range of Star City, near Moscow. Sometimes, it is just a carrier; at other times, you hear Russian voices.

Occasionally, English is heard when NASA astronauts are talking back to the ground.

During some passes, there is nothing at all. However, it is a good frequency to put into your scanner and to enjoy surprising you from time to time.

During spacewalks, it is worth listening on 121.125MHz and 121.750MHz, both on FM. You may hear signals on these frequencies from the spacesuits that the space-walking astronauts are using. Signals are surprisingly strong, even when you are using a simple antenna. Although the ISS is around 260m above us, there isn’t much in the way!

Another frequency worth scanning is 145.800MHz, which is an amateur radio frequency used by the space station. You will sometimes hear an astronaut addressing questions to a ground station, which you may not be able to hear.

These sessions normally involve a school or college. You can check to see what contacts are coming up at this dedicated URL:

As a rule of thumb, if you are based in the UK, you should be able to hear any of the contacts scheduled in Europe. Signals are very strong; again, you will be able to hear them on a handheld scanner (it will be better if you go outside, rather than staying inside the house).

You may find it worth rotating the scanner/aerial around vertically and horizontally until you get the strongest signal. On 145.800MHz, you will occasionally hear a ‘burble’ of tones. This is usually Slow Scan Television (SSTV) sent from the Space Station. It is quite simple to decode, using MMSSTV software on your PC, but there are even SSTV decoders for smartphones.

I have successfully decoded pictures by holding the phone close to the loudspeaker of a handheld or mobile radio when I have been out and about and heard the SSTV start.

Somewhere else you can listen for signals from space is 149.940MHz, which is the Cosmos 2463 satellite (you can get pass predictions from the Heavens Above website or your favourite satellite pass app on your smartphone). This is just a data signal, but it should have the tell-tale Doppler shift of a satellite signal. This means that the frequency falls during the time of the satellite pass, which is quite interesting if you haven’t heard it before.

Cosmos 2454 is also noted as active on the same frequency, so it may be worth listening for that satellite as well. These satellites also send a Morse code signal on 399.840MHz (based on the data signal frequency multiplied by 8/3) which might be worth listening for if you can listen on CW/SSB in that part of the band.

Hopefully, all this has whetted your appetite for listening to some signals from space. Please give it a go and let me know how you get on.

There’s plenty more that you can hear from other satellites and we’ll come back to that in future columns.


Weather Satellites

Keeping up with the satellite theme, like most British people, I love to know about the weather. Some readers have had a great deal of success decoding images from the weather satellites around 137MHz.

For instance, Kevin Hewitt (Gibraltar) received and decoded the excellent images shown in Figs 2 and 3.

In the first image (Fig. 2, of 6th June), you can see thunderstorms out over Central Europe as well as some very clear skies over Ireland. Kevin used an R2ZX receiver with a manually-tracked VHF log periodic Yagi aerial. He decoded the images from the NOAA-19 satellite during an (almost) overhead pass and was using the WXtoImg software. I am impressed with the quality of the image in Fig. 2, and I would like to return to this subject in future columns, as I think that many readers are likely to want to try this for themselves!


Future Columns

In future columns, I would like to offer a combination of news and things to try for yourself. Please let me know what you are up to! What are you listening to? What have you heard for the first time? Have you been trying a new aerial? Have you been listening online, making use of one of the WebSDR receivers available?

Most importantly: What would you like to read about in this column?

My aim is to be able to cover subjects each month which contain something new for you to try; hopefully in a simple manner and with equipment that you already have.

In order to achieve this, however, I will need your help and it would be really great to hear from you. You can email me at the email address at the top of the column and you can find me on Twitter too.

Moreover, you can often find me on Zello, generally on the Network Radios channels, which, don’t forget, are open to anyone who has any interest in Radio.

That’s it for this month and for my first column in RadioUser.

I will see you next month, and: Happy Scanning!


This article was featured in the September 2018 issue of Radio User

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