Idiots guide to SDR airband?
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Idiots guide to SDR airband?
Greetings all,
Wondering if anyone here has experience with the RTL dongles for airband listening? I've moved to a location which happens to be a mile away from a reasonably busy airport so should be within range to receive the comms from both sides.
I was hoping to be able to simply purchase an off-the-shelf dongle, plug it in and set it going but all I'm seeing on sites like ebay and amazon are literally hundreds of different RTL-SDR model numbers all claiming to receive the entire frequency bandwidth and it's all a bit overwhelming for a tech noob like me.
I've read bits and pieces that say you need a certain type otherwise the transmissions get bled all over by strong FM stations and you can't hear anything but I don't know if there's any truth to that, hence wanting advice from any SDR users on the best way forward.
Thanks.
Wondering if anyone here has experience with the RTL dongles for airband listening? I've moved to a location which happens to be a mile away from a reasonably busy airport so should be within range to receive the comms from both sides.
I was hoping to be able to simply purchase an off-the-shelf dongle, plug it in and set it going but all I'm seeing on sites like ebay and amazon are literally hundreds of different RTL-SDR model numbers all claiming to receive the entire frequency bandwidth and it's all a bit overwhelming for a tech noob like me.
I've read bits and pieces that say you need a certain type otherwise the transmissions get bled all over by strong FM stations and you can't hear anything but I don't know if there's any truth to that, hence wanting advice from any SDR users on the best way forward.
Thanks.
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Before proceeding further, it has to be mentioned that listening to Airband Transmissions in the UK is generally illegal, but you can read the sticky note on this forum for the details. Now we have that clear...
I suggest you check the amateur radio websites. The Radio Society of Great Britain (RSGB) has links to useful information.
The dongles intended for digital TV reception can be repurposed as wideband receivers by downloading a couple of computer programs, one to operate the dongle, one to act as an on screen tuner to select the frequency and receiver mode required. The dongles are wide open in terms of frequencies they can receive. Strong local stations can wipe out more distant weaker signals even though the frequencies being received are relatively far apart.
For airband reception, interference from pagers and FM broadcast stations are the biggest bug bear. For best reception, you need to make up a filter to match the frequencies you want to listen to. This blocks the unwanted signals between the aerial and your receiver dongle. These filters can be made with a small coil of enamelled copper wire and a couple of capacitors. All stuff that can be bought cheaply at Maplins.
There is a bit of a steep learning curve, but there is plenty of information on the Internet and YouTube videos showing you what to do. The dongles work very well indeed for the money and are a very good and cheap way to dip your toe in the water to see if you want to consider a more sophisticated purpose built receiver. Dedicated airband and wider frequency handheld and desktop scanners are available from £60 or so, but the satisfaction and experience gained from getting one of these dongles working well is priceless.
You may see some commercially available dongles that claim to be dedicated for airband or other frequencies. Most of these are just repackaged RTL-SDR dongles with a filter built in and software included, all sold at a hugely inflated mark up. There are some exceptions such as a dongles sold for receiving Cube Sat transmissions, but they are few and far between.
Another advantage of computer based systems is that they can be left unattended and software used to record transmissions of interest for review later. Avoids all that listening to nothing but static!
So long as you do not communicate anything heard to any third party or make use of the information for any nefarious purpose, no one is any the wiser. Google searches will reveal a wealth of information which initially seems overwhelming, but you will soon learn that there are two or three main products that work well for most people.
I suggest you check the amateur radio websites. The Radio Society of Great Britain (RSGB) has links to useful information.
The dongles intended for digital TV reception can be repurposed as wideband receivers by downloading a couple of computer programs, one to operate the dongle, one to act as an on screen tuner to select the frequency and receiver mode required. The dongles are wide open in terms of frequencies they can receive. Strong local stations can wipe out more distant weaker signals even though the frequencies being received are relatively far apart.
For airband reception, interference from pagers and FM broadcast stations are the biggest bug bear. For best reception, you need to make up a filter to match the frequencies you want to listen to. This blocks the unwanted signals between the aerial and your receiver dongle. These filters can be made with a small coil of enamelled copper wire and a couple of capacitors. All stuff that can be bought cheaply at Maplins.
There is a bit of a steep learning curve, but there is plenty of information on the Internet and YouTube videos showing you what to do. The dongles work very well indeed for the money and are a very good and cheap way to dip your toe in the water to see if you want to consider a more sophisticated purpose built receiver. Dedicated airband and wider frequency handheld and desktop scanners are available from £60 or so, but the satisfaction and experience gained from getting one of these dongles working well is priceless.
You may see some commercially available dongles that claim to be dedicated for airband or other frequencies. Most of these are just repackaged RTL-SDR dongles with a filter built in and software included, all sold at a hugely inflated mark up. There are some exceptions such as a dongles sold for receiving Cube Sat transmissions, but they are few and far between.
Another advantage of computer based systems is that they can be left unattended and software used to record transmissions of interest for review later. Avoids all that listening to nothing but static!
So long as you do not communicate anything heard to any third party or make use of the information for any nefarious purpose, no one is any the wiser. Google searches will reveal a wealth of information which initially seems overwhelming, but you will soon learn that there are two or three main products that work well for most people.
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I wasn't originally going to reply to this thread, simply because I haven't got any positive suggestions or experiences to help Getaway Turtle's attempts at using an SDR (Software Defined Radio) USB dongle. However, sometimes sharing even a negative experience can at least add a little to the discussion, so here I am.
First off, I acknowledge G0ULI's valid and polite comments on the legalities of a non licence holder listening in on airband transmissions, indeed there are other contributors here on PPRune who are so vociferous and vehemently opposed to any such activity that I imagine them frothing at the mouth as they type their opinions! They'll be along shortly to add their 'two-penn'orth' to this discussion. Anyway, thats for another day maybe.
A few months back, I got me one of these gadgets (based on the R820T RTL2832U chip) for the same purpose as Getaway Turtle, and hoped furthermore to find software that would allow the thing to be used as a scanner type receiver working alongside an Icom IC-R5. Just for clarity, these dongles were designed and intended originally for digital television reception, but their extraordinary 'wideband' receiving performance makes them theoretically at least suitable for airband purposes. It was hooked up to an Icom AH7000 discone antenna, and despite being close to the flight paths of Heathrow, Gatwick, Southend, Luton and Stansted, I never picked up even one airband transmission!! G0ULI is probably right about FM broadcast stations swamping all other transmissions, although one of the pieces of software I used lets the user narrow the 'selectivity' which should filter out adjacent frequencies.
For the record, the following SDR programs were used: HDSDR, SDR Console, and SDR Sharp.
Edit to add just for fun: One of my classmates from school 40 years ago is today flying BA 777's out of Heathrow apparently. I haven't seen nor heard him in all that time, but I think possibly... just possibly heard him as a BA 777 was in the Lambourne hold a year ago!!
First off, I acknowledge G0ULI's valid and polite comments on the legalities of a non licence holder listening in on airband transmissions, indeed there are other contributors here on PPRune who are so vociferous and vehemently opposed to any such activity that I imagine them frothing at the mouth as they type their opinions! They'll be along shortly to add their 'two-penn'orth' to this discussion. Anyway, thats for another day maybe.
A few months back, I got me one of these gadgets (based on the R820T RTL2832U chip) for the same purpose as Getaway Turtle, and hoped furthermore to find software that would allow the thing to be used as a scanner type receiver working alongside an Icom IC-R5. Just for clarity, these dongles were designed and intended originally for digital television reception, but their extraordinary 'wideband' receiving performance makes them theoretically at least suitable for airband purposes. It was hooked up to an Icom AH7000 discone antenna, and despite being close to the flight paths of Heathrow, Gatwick, Southend, Luton and Stansted, I never picked up even one airband transmission!! G0ULI is probably right about FM broadcast stations swamping all other transmissions, although one of the pieces of software I used lets the user narrow the 'selectivity' which should filter out adjacent frequencies.
For the record, the following SDR programs were used: HDSDR, SDR Console, and SDR Sharp.
Edit to add just for fun: One of my classmates from school 40 years ago is today flying BA 777's out of Heathrow apparently. I haven't seen nor heard him in all that time, but I think possibly... just possibly heard him as a BA 777 was in the Lambourne hold a year ago!!
Last edited by Ant; 4th Mar 2017 at 18:27.
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Ant
You appear to have the same set up I experimented with. The wideband signals picked up by the discone antenna will completely overload the front end of the dongle receiver, which is why you didn't receive anything worthwhile. The antenna you used was simple too good!
Getaway Turtle
The dongles have very sensitive receivers that are easily overloaded. The best bet when starting out is to connect a couple of feet of wire to the centre connection in the antenna socket of the dongle. This should pick up local FM radio and various other stations. You may even hear some airband stuff if it is very local.
Once the system is proved to be working, connect a length of coax cable using a suitable adapter plug and adapter to the antenna socket. Mount the far end of the cable as high up as possible, preferably in the loft or near the ceiling in an upstairs room. Connect up two lengths of wire 60 centimetres (2 feet) long to the end of the coax, one wire to the centre of the coax, one wire connected to the braid. Arrange these wires vertically with the center connect wire uppermost. The wires can be stuck down to a non conducting surface like a bit of bamboo or a stick to keep them out straight and supported vertically. Use a bit of insulating tape to keep the connections from sorting out. Especially keep an eye out for stray wisps of braid that tend to get wrapped around the centre conductor of the coax. That would short out all the signals you are trying to receive! Soldered connections are great if you have a soldering iron, but twisted connections are good enough.
This arrangement will form a half wave dipole antenna tuned to approximately 125 MHz which is around the middle of the airband frequencies you want to receive.
This type of antenna arrangement will tend to be less sensitive to transmissions away from the airband frequencies, so provides a degree of filtering from unwanted signals. You should certainly pick up local transmissions with this type of setup.
Remember, airband signals are AM modulated, so make sure you select the correct receive mode in the receiving software. Airband signals travel essentially along lines of sight. You may hear aircraft many miles away at altitude, but just barely receive a ground station five miles away, or not at all if there is a hill or high buildings in the way. Hence the desirability of having an antenna as high up as possible.
Cheap TV or satellite coax cable can be used, and the wire for the antenna can be stripped mains cable, or whatever you have to hand. This project shouldn't cost any more than £20, even buying everything from scratch.
Good luck.
You appear to have the same set up I experimented with. The wideband signals picked up by the discone antenna will completely overload the front end of the dongle receiver, which is why you didn't receive anything worthwhile. The antenna you used was simple too good!
Getaway Turtle
The dongles have very sensitive receivers that are easily overloaded. The best bet when starting out is to connect a couple of feet of wire to the centre connection in the antenna socket of the dongle. This should pick up local FM radio and various other stations. You may even hear some airband stuff if it is very local.
Once the system is proved to be working, connect a length of coax cable using a suitable adapter plug and adapter to the antenna socket. Mount the far end of the cable as high up as possible, preferably in the loft or near the ceiling in an upstairs room. Connect up two lengths of wire 60 centimetres (2 feet) long to the end of the coax, one wire to the centre of the coax, one wire connected to the braid. Arrange these wires vertically with the center connect wire uppermost. The wires can be stuck down to a non conducting surface like a bit of bamboo or a stick to keep them out straight and supported vertically. Use a bit of insulating tape to keep the connections from sorting out. Especially keep an eye out for stray wisps of braid that tend to get wrapped around the centre conductor of the coax. That would short out all the signals you are trying to receive! Soldered connections are great if you have a soldering iron, but twisted connections are good enough.
This arrangement will form a half wave dipole antenna tuned to approximately 125 MHz which is around the middle of the airband frequencies you want to receive.
This type of antenna arrangement will tend to be less sensitive to transmissions away from the airband frequencies, so provides a degree of filtering from unwanted signals. You should certainly pick up local transmissions with this type of setup.
Remember, airband signals are AM modulated, so make sure you select the correct receive mode in the receiving software. Airband signals travel essentially along lines of sight. You may hear aircraft many miles away at altitude, but just barely receive a ground station five miles away, or not at all if there is a hill or high buildings in the way. Hence the desirability of having an antenna as high up as possible.
Cheap TV or satellite coax cable can be used, and the wire for the antenna can be stripped mains cable, or whatever you have to hand. This project shouldn't cost any more than £20, even buying everything from scratch.
Good luck.
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Thank you G0ULI for your valuable technical contribution. I really had almost thrown away the dongle I mentioned above, but now feel encouraged to do some further experimentation, and hope sincerely that the original poster, Getaway Turtle as well as any other interested enthusiasts will also be encouraged. Lets compare notes again in a few weeks time and see how we get on. I look forward to that.
Just by the by: would that be G0ULI, as in Golf Zero Uniform Lima India??
From Ant, as in Mike 6 Foxtrot Sierra November! So I WAS licenced after all, though not for the purposes of airband.
Just by the by: would that be G0ULI, as in Golf Zero Uniform Lima India??
From Ant, as in Mike 6 Foxtrot Sierra November! So I WAS licenced after all, though not for the purposes of airband.
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Yes it is, rather incredibly, my officially issued callsign. I also hold full commercial air and marine licences, so I feel authorised to listen to those frequencies.
73s
Yes it is, rather incredibly, my officially issued callsign. I also hold full commercial air and marine licences, so I feel authorised to listen to those frequencies.
73s
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I also hold full commercial air and marine licences, so I feel authorised to listen to those frequencies.
Also, I'm hoping Getaway Turtle and other followers of this thread might over the the next few weeks or so share experiences of using the cheaply available and technically interesting SDR dongles available out there!
73s
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I have used one of the Devices mentioned to pick up the local transmitter and airfields with no problem (just testing it please note!) The filtering is not great but, hey, for the price i didn't expect that. I brought it to use on 23cms which It worked fairly well!
73
73
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What an awesome thread this is and what a find 
As a kid I had this expensive handheld scanner (Cobra SR-15) that I remember saving up forever for. It served me well, even after the NiCd became useless. One day after trying to wire it up to my car's audio system I accidentally connected a power supply wire to the audio out and fried it (one of the triacs I think).
I spent ages trying to repair it and learnt a lot in the process, particularly about the discriminator chip that was popular at the time. Alas, the circuit board itself started showing signs of the copper paths detaching and the unit is now destined for the bin (although I still have it for it's clever design).
Enter SDR - I never even knew it existed.
Thank you to those that raised the subject and posted some very insightful information. This is an incredibly cheap way of getting back into my past fun and popular hobby.
As a kid I had this expensive handheld scanner (Cobra SR-15) that I remember saving up forever for. It served me well, even after the NiCd became useless. One day after trying to wire it up to my car's audio system I accidentally connected a power supply wire to the audio out and fried it (one of the triacs I think).
I spent ages trying to repair it and learnt a lot in the process, particularly about the discriminator chip that was popular at the time. Alas, the circuit board itself started showing signs of the copper paths detaching and the unit is now destined for the bin (although I still have it for it's clever design).
Enter SDR - I never even knew it existed.
Thank you to those that raised the subject and posted some very insightful information. This is an incredibly cheap way of getting back into my past fun and popular hobby.
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I used to use a $20 dongle for ADS-B until the computer caught fire. It was pretty easy to set up, and I could listen to radio on it, too. Don't think I ever tried airport radio, but it should be in the available frequency band.
Edit: looks like this is the one I was using: https://www.amazon.ca/dp/B00CM3LNMM/
Edit: looks like this is the one I was using: https://www.amazon.ca/dp/B00CM3LNMM/
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Any dongle with that specific chipset will work fine. Go for the cheapest one you can find. The price difference between suppliers may be due to the quality or quantity of extras and software supplied. As you will only be using the dongle, don't spend more than you need.
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Gentlemen, sorry for late reply. I forgot to bookmark the thread and forgot about it! Thanks for your input.
I was hoping for an off-the-shelf solution as far as the SDR dongle goes rather than spending time experimenting with different software and tweaking settings that frankly aren't really of any interest to me. I may go for one of the off-the-shelf airband configured ones on Ebay as I don't mind the extra expense if it means I don't have to mess around with it. I know HAMs are into all this tweaking and get a great deal of enjoyment from it but I am not a HAM and just want something that "works" out of the box.
I am 1 mile to the east of LBA in the Adel area so I'm hoping I should be able to pick up the tower with a loft antenna like a J-Pole if it will fit, although there is a bit of a hill in the way.
I am also well aware of the frothing that topics on listening to UK ATC seems to attract and checking some old threads here this site seems to have more than its fair share of frothers too!
Not sure why as there are a handful of public feeds for listening to UK ATC now if you know where to look and none have attracted any interest from OFCOM whatsoever.
I was hoping for an off-the-shelf solution as far as the SDR dongle goes rather than spending time experimenting with different software and tweaking settings that frankly aren't really of any interest to me. I may go for one of the off-the-shelf airband configured ones on Ebay as I don't mind the extra expense if it means I don't have to mess around with it. I know HAMs are into all this tweaking and get a great deal of enjoyment from it but I am not a HAM and just want something that "works" out of the box.
I am 1 mile to the east of LBA in the Adel area so I'm hoping I should be able to pick up the tower with a loft antenna like a J-Pole if it will fit, although there is a bit of a hill in the way.
I am also well aware of the frothing that topics on listening to UK ATC seems to attract and checking some old threads here this site seems to have more than its fair share of frothers too!
Not sure why as there are a handful of public feeds for listening to UK ATC now if you know where to look and none have attracted any interest from OFCOM whatsoever.
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Well there are laws and the enforcement of laws...
A phone call to either Waters and Stanton or Martin Lynch and Son will get you advice and be able to supply what you need. Both suppliers are main dealers for all the main brands and have internet sites to browse or physical stores if you want to visit.
If you still think you might want to use a computer, the Funcube Dongle+ at £149.99 covers a huge range of frequencies and has built in filters for various bands. There is a coverage gap between 250-410MHz which rules out military airband, but otherwise this is a very good receiver that is not much bigger than a USB memory stick. Check the details and reviews on the internet. I use one of these and the performance is considerably better than the repurposed TV dongles, but I listen to a very wide range of broadcasts across all the amateur bands from short wave to UHF.
The Funcube Dongle was originally produced as part of a project to enable schools to monitor data from micro satellites as they passed overhead, so they have plenty of sensitivity and the ability to receive satellites with a very basic home made antenna. Airband is trivial by comparison.
There are alternative receivers that operate in a similar manner, above and below this price. A certain amount of fiddling with the software and setting up will inevitably be involved with all computer based receivers, but once the system is up and running, it is usually very stable. While the computer software tends to get updated fairly frequently, you can stick with whatever version works for you. There is generally no need to keep updating unless it fixes a bug that is bothering you or introduces a new feature you want.
Handheld receivers by Yeasu, Icom and Kenwood are the gold standard and priced appropriately. There is some good cheap stuff available direct from China. Again, check the internet for comments and reviews. Handheld scanners are useful because they can be used anywhere, but do need batteries replacing or charging arrangements. Most work 8-10 hours on a set of batteries or a fresh charge.
Remember, you need to be able to receive AM transmissions on airband and the frequency steps at 8.33 kHz rather than the 12.5, 25 and 50 kHz tuning steps used in other bands. Most older receivers with 12.5 kHz tuning have a sufficiently broad receiving bandwith to hear 8.33 kHz transmissions if tuned slightly above or below the exact frequency.
A phone call to either Waters and Stanton or Martin Lynch and Son will get you advice and be able to supply what you need. Both suppliers are main dealers for all the main brands and have internet sites to browse or physical stores if you want to visit.
If you still think you might want to use a computer, the Funcube Dongle+ at £149.99 covers a huge range of frequencies and has built in filters for various bands. There is a coverage gap between 250-410MHz which rules out military airband, but otherwise this is a very good receiver that is not much bigger than a USB memory stick. Check the details and reviews on the internet. I use one of these and the performance is considerably better than the repurposed TV dongles, but I listen to a very wide range of broadcasts across all the amateur bands from short wave to UHF.
The Funcube Dongle was originally produced as part of a project to enable schools to monitor data from micro satellites as they passed overhead, so they have plenty of sensitivity and the ability to receive satellites with a very basic home made antenna. Airband is trivial by comparison.
There are alternative receivers that operate in a similar manner, above and below this price. A certain amount of fiddling with the software and setting up will inevitably be involved with all computer based receivers, but once the system is up and running, it is usually very stable. While the computer software tends to get updated fairly frequently, you can stick with whatever version works for you. There is generally no need to keep updating unless it fixes a bug that is bothering you or introduces a new feature you want.
Handheld receivers by Yeasu, Icom and Kenwood are the gold standard and priced appropriately. There is some good cheap stuff available direct from China. Again, check the internet for comments and reviews. Handheld scanners are useful because they can be used anywhere, but do need batteries replacing or charging arrangements. Most work 8-10 hours on a set of batteries or a fresh charge.
Remember, you need to be able to receive AM transmissions on airband and the frequency steps at 8.33 kHz rather than the 12.5, 25 and 50 kHz tuning steps used in other bands. Most older receivers with 12.5 kHz tuning have a sufficiently broad receiving bandwith to hear 8.33 kHz transmissions if tuned slightly above or below the exact frequency.
