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WTR Browser, Satellites, Squawker and Signals from Deep Space


Chris Lorek, in one of his last columns for RadioUser, mentioned the WTR Browser software written by Wayne Richards



Chris Lorek, in one of his last columns for RadioUser, mentioned the WTR Browser software written by Wayne Richards (Fig. 1). The software uses Ofcom Business Radio data and other sources, in database form.

It provides the ability to search through the database filtering results by a number of data fields, such as frequency, grid reference, emission type (DMR or NBFM and so on).

It is a great tool and helps scanner enthusiasts with the perennial question of, what shall I listen to?

If you have not taken a look at the software as yet, it is well worth doing so. Just a quick search in the database for the area around my West Oxfordshire home came up with some frequencies that look to be well worth a listen. As well as Business Radio, the WTR Browser software covers Airband, Amateur Radio and other frequency lists. Very useful indeed.

However, if that wasn’t enough, the latest release allows you to integrate the software with compatible scanners, so that when the scanner stops on a frequency, it uses the integration to the computer to look up the frequency in the WTR Browser software and will provide what information it finds.

You might want to check up on the WTR Browser Group on Facebook for information about exactly which scanners are supported, but many Whistler, Uniden and AOR units are covered at the moment, with other scanners and an SDR dongle being worked on at the time of writing.

Mike Burgess, who kindly wrote in with the details of the changes to the software also provided a link to a sample installation video, which shows how to integrate WTR Browser with a scanner:

WTR Browser costs £7.


Squawker Software

If your interest in scanning is predominantly in airband, then Squawker is a piece of software, written by Rick King, which is similar in style to WTR Browser. As you might expect, it only contains airband (both civil and military) frequencies (Fig. 2).

Along with the frequencies, there is a database of ‘squawk’ codes, which are used by various air traffic control centres to aircraft for use in their transponders. Using this, you can have an idea of who the aircraft is in touch with, should you hear or see a ‘squawk’ code.

Like WTR Browser, there is the ability to integrate with various scanners, so that you have a display of what ATC centre your scanner is listening to.

You can also produce a file in comma separated variable (.csv) format, containing particular frequencies. These can then be used to populate a scanner’s memories.

I played around with Squawker and found it of great value in finding some new and interesting frequencies to listen to on the airband. Squawker costs £5.

If you’d like to see a video about Squawker, take a look at this URL:

The Squawker program itself can be downloaded from here:

I am grateful to Mike Burgess and Rick King for taking the time to write and let me know about these very useful utilities. If you write or use a utility with your scanner that you’d like included in the column, don’t hesitate to drop me a line, it would be great to share it with all our readers.


Receiving NOAA Weather Satellite Images

Kevin Hewitt kindly put together a description of the method that he uses to receive the excellent NOAA weather satellite images we featured last month. Kevin said, ‘I receive NOAA (National Oceanic and Atmospheric Administration) APT (Automatic Picture Transmission) weather satellite images, portable in Gibraltar. My set up comprises of an R2ZX APT satellite receiver powered by eight AA batteries, a 2m/ 70cm log periodic aerial, tracked by hand and a Win7 Notebook PC running WXtoImg.

“The audio output of the R2ZX is fed into the Notebook microphone input. ISS Detector Pro, an Android App, provides pass predictions and the direction/ elevation to point the aerial. Satellite pass predictions are also available at this website:

“I have received good images using a homemade 2m three-element tape measure Yagi aerial, a two-element ‘rabbit ears’ Yagi antenna and a simple, ‘rabbit-ears’, V-dipole. The ‘rabbit-ears’ TV aerials are Pound Store purchases and the telescopic sections extend to 50 - 60cm.

“Currently, three NOAA satellites are active: NOAA 19 on 137.100MHz, NOAA 18 on 137.9125MHz and NOAA 15 on 137.620MHz, using the APT format. The bandwidth of APT is around 30kHz – too wide for most scanners. Future satellites will not use the APT format.

“DVB-T USB sticks containing the RTL820T or RTL820T2 chipset, and costing around £10, can be used to receive APT transmissions. Using SDR# (‘SDR Sharp’) to control the RTL-SDR dongle, the audio is piped via VBCable (Virtual Audio Cable) to WXtoImg. The WXtoImg (‘Weather-to-Image’) software will decode and process the APT data, and it produces the weather satellite images.

“The article 'Receiving APT Weather Images from NOAA Satellites using an RTL-SDR Dongle', by Devendra Kulkarni, appeared in the GEO Quarterly Journal No 51. It can be downloaded at this URL:

It covers the above procedure in detail.

“In the UK, pagers operate on 138MHz. The very strong signal-breakthrough on 137MHz interferes with the satellite signal and can spoil many satellite images.’

Someone else who has had a great deal of success decoding NOAA weather images is Pete Goodhall, who lives in Elgin. Pete uses an Airspy receiver and a quadrifilar helicoidal (QFH) antenna. He decodes the data using the WXtoImg software. Pete automatically uploads the decoded images onto his website here:

As well as images being displayed on the website, another useful feature is that Pete displays the times of upcoming NOAA satellite passes, along with the frequencies on which to listen.

If you fancy trying to hear the satellite – and you should be able to hear it on a simple vertical or dipole, albeit you may get some ‘banding’ as the satellite moves through the pattern of your antenna – have a go using these times and see what you can hear.

Even decoding a noisy picture is exciting when you get started!


The Amateur Deep Space Network

For some time, I have admired on Twitter the results of Paul Marsh, who specialises in receiving signals across huge distances from spacecraft well beyond earth orbits – way out into the solar system (Fig. 3).

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Therefore, I asked Paul if he would consider letting me have some details about his setup and what it’s all about, for this column. He has written such an interesting piece that – in order to do justice to it – I would like to include an introduction this month and then some more details next month.

In the future, Paul has kindly agreed to keep us posted about the spacecraft he is tracking and where they are. Paul takes up the story:

“NASA and the European Space Agency operate a global network of very large dish antennas to receive and process signals from spacecraft operating away from Earth. For example, there are daily communications sessions between Earth and the Mars orbiters. Spacecraft in dynamic environments such as observing comets or asteroids require additional DSN network time as there is a large amount of data to gather. Amateur DSN enthusiasts aim to be able to detect the very weak signals, using small antennas.

“This area of the hobby is interesting because signals tend to always get weaker as the spacecraft travel further from Earth, meaning that advances in low-noise amplifiers and software processing techniques have to evolve to continue to track the spacecraft and detect signals from them.

“A typical HF or short wave DXer might be pleased to receive signals from New Zealand or Australia, but in the Amateur DSN world, these distances are tiny. For example, at my station, spacecraft closer than 500 million km are not regularly observed, because there is no longer any technical challenge in receiving them unless there are exceptional circumstances such as operating in the Ka (32GHz) band, which adds another layer of technical complexity.

“For DX chasers, really there is no other area of the hobby that allows you to detect signals from distant spacecraft. An additional bonus of this area is that you will learn about spacecraft orbital dynamics, planetary motion, microwave design, build and optimisation techniques, and have a lot of fun in the process.

“The majority of spacecraft carry 8.4GHz transmitters / transponders for telemetry, science data and ranging operations, and this is the band that we'll concentrate on since it's comparatively the most straightforward to build equipment for.

“How do build a system? First, it cannot really be done in a weekend; it needs some planning to work out what you want from your receiving system, and what you can get away with in terms of dish size (it helps a lot if you have a very tolerant wife). A basic system might consist of a 1.2m ex-satellite TV dish, home built feed, de-polariser, low-noise amplifier (LNA), downconverter, and off-the-shelf software radio to process the signal (AirSpy, RF-Space and so on).

Next month, I will include some more details about how Paul has built his station and the challenges he has overcome to receive such fascinating signals. A huge thank you to Paul for so generously sharing his expertise in this area.


Listening Post

Each month from now on, I am hoping to include a ‘listening post’ section in this column. This will allow us to share what we have been listening to – especially any interesting or unusual loggings!

Please drop me an email if you’d like to contribute – a very quick email is enough, and I will do the rest. It will be great to hear from you.

If like me, you live away from the sea, but love listening to the marine band traffic on VHF, you might be interested to learn about a channel I discovered recently on Zello – one of the Voice over IP platforms that Chris Rolinson covers in his Network Radios column here in RadioUser.

If you set yourself up on Zello and then search for the EI7DAR_Marine channel, you’ll be able to listen to marine traffic as heard from the east coast of Ireland. This includes shore stations on both sides of the Irish Sea and, of course, vessels of varying size on the sea.

It makes for good listening! Don’t forget, you can setup Zello on your mobile phone or your PC, so you can probably listen on a device that you already have.

David Lees reminded me recently that even if you are away from the sea, it’s often worth scanning marine Channel 16, as there may be aircraft engaged in search and rescue activity on the channel, which, of course, you might hear, owing to the greater range of airborne transmissions.

If you had your scanner running on 145.800MHz around July 31st, you might have heard some musical sounding tones, which were Slow Scan Television (SSTV) signals from the International Space Station.

Twitter was full of people’s captures of the different images that were transmitted but one of the ones that impressed me most was from Dawn Denyer.

Dawn used a handheld receiver and rubber duck antenna to receive the signals and the Robot 36 SSTV Decoder application on her phone to display the picture (Fig. 4).

Don’t forget that it’s sometimes easier to record the SSTV audio at the time (you can even use your mobile phone) and then feed that into an SSTV decoder at your leisure. Signals from the space station are generally strong and easily audible on simple antennas.

Spending some time on the west coast of Wales recently, I enjoyed listening to the VHF Marine band and noted transmissions from various Irish coastguard stations both north and south of the border, Holyhead, Milford Haven and Falmouth coastguard.

Chatting to Steve Hathaway who lives in Angle, Pembrokeshire, he had recently heard signals from Humber Coastguard, on the opposite side of the country – good reception indeed. In the same period of tropospheric enhancement, Bilbao Port Control from Spain was clearly audible to vessels in the Irish Sea.


Using AIS for Distant Marine Signals

It’s always interesting to see how marine signals can sometimes travel great distances over the sea – you’ll often see this happen during periods of prolonged high pressure.

One of the ways that you can observe this is using AIS transmissions from ships.

As many readers will know, AIS stands for Automatic Identification System and for ships, is like ADS-B for aircraft. A beacon is transmitted from the ship periodically, which contains information on the position, heading of the vessel, its name and other information such as its destination and cargo. If you’ve not had a look at AIS, I highly recommend it – take a look at this website  

It will show you where the vessels are, enable you to track them and so on. If you live by the coast, it will give you a great idea of what the ships are that you are seeing. And of course, it’s fascinating to know where the ships are when you hear them on your scanner.

Allow me to go back to the ability of AIS to give you an idea of whether or not VHF conditions are enhanced. In this context, you may, for example, be in with a chance of receiving distant marine or other VHF stations.

You can use an AIS receiver you know the usual coverage of. There’s a very useful one available on the web, which is based on the Isle of Wight:

Once you start to get an idea of the usual coverage of it, you will notice if the receiver is starting to receive much more distant ships than normal, alerting you to the fact that something is up!

Of course, the next step is to set up your own AIS receiver, which again you can do with nothing more complicated than a cheap RTL-SDR dongle and a Raspberry Pi.

We’ll come back to that in future columns.

That’s it for this month! Thank you to everyone who has contributed to the column this time. I welcome everyone’s contributions and I’d like to make the content as varied as possible, ranging from things that everyone can do, to more specialised, but fascinating, topics like the Deep Space Network.

Please DO get in touch, it will be great to hear from you.


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

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