Could someone tell me the ultra simplified differences, pros, and cons when compared to each other and only in regards to Rx between scanners, receivers, sdr's, and what else is out there?
Scanner vs Receiver vs SDR vs ...?
- Thread starter kafw4202
- Start date
- Status
br0adband
Member
Disclaimer: I'm doing this off the top of my head based on my own experience with using such hardware over the past 40 years or so - these are my definitions of scanner, receiver, and SDR. Also, a very long post ahead so be warned, and no it's not ultra-simplified but I suppose that depends on what you're hoping for. 
Scanner = using the most common usage of the term would be a device which is used to scan (literally) frequencies that are either programmed in or scanned manually looking for "new" ones you may have not heard anything on previously. I would hazard to say that using the term "scanner" means something that you'd using to monitor police, fire, EMS, and other things in your local area because again that's the most common usage of the term. "Police scanner" is easy to understand and if you went into an electronics shop most anywhere and asked for that would be immediately understood. They traditionally come in two main form factors: handhelds and mobile/base models. Handhelds are obviously small and portable, while the mobile devices are designed to be used in vehicles but can easily just be used at home or wherever as a "base" station scanner just as easily. The basic difference is a handheld is extremely portable and self-contained where a mobile/base usually require a dedicated power supply of some kind and a dedicated attached antenna that are not part of the device itself as a handheld happens to be.
A scanner of such type is limited to the hardware it's designed with so in effect you're "stuck" with whatever the hardware maker chose to allow the hardware to be able to monitor - what I mean by this is if you have a purely analog scanner which can only receive analog transmissions (basically the concept of an AM or FM radio for listening to audio/music) then that's pretty much all you're going to be able to monitor. Newer scanners can do more by having extra circuitry onboard to receive digital communications - the term there is a bit tough to grasp for some because in effect they're analog transmissions in reality, they're just broadcasting content in the audible spectrum that is then decoded similar to how data is sent using an old school dialup modem on a computer. If you were to listen in on the actual communications used by dialup modems you'd hear that familiar screeching audio sound that modulates based on the particular protocol in use. A very old 300 baud modem would sound one way, a 2400 another, a 14.4 model yet another, 28.8, 56K etc and so on.
Digital communications are analog transmissions of a modulated audio signal (that you can hear, there are dozens of them and you can get some idea of what you'd be picking up at this page which is a great source of info on tracking down those odd blips, bleeps, and screeches you'd hear on various frequencies using a scanner or receiver or SDR hardware.
Some digital comms are very popular nowadays like APCO P25 Phase I which is a worldwide standard form of digital comms and has been for some time. It's been improved upon with Phase II but Phase II decoding is still relatively new and while a few handheld models exist from Uniden and GRE/Whistler, there are other modes like DMR aka MOTOTRBO, NexEdge aka NXDN, and several others that simply cannot be monitored with any modern scanner. Having said that, if you happen to have a good quality scanner you can probably work a setup that feeds the signal received by the scanner to a computer which can run software to decode those other digital modes, with DSD+ aka DSDPlus being the favorite right now. It's in active development and a fantastic piece of software that's not too difficult to figure out for most anyone.
Receiver = using the most common usage of the term would mean one of the larger dedicated pieces of hardware from brand name companies like AOR, Icom, Yaesu, Kenwood, and so on. They're primarily designed for shortwave reception (don't hate on me for saying this, please, because it's true for the most part) but some models, especially the high end ones from Icom and AOR, can handle frequencies from the lowest of the lows to the highest of the highs meaning well into the gigahertz range without breaking a sweat. They're not "scanners" in that sense, they are very narrow purpose devices that are traditionally manually operated (with a big tuning dial and a frequency display of various kinds), as well as having the ability to be transceivers as well in some cases so they not only receive but allow for transmission on given frequencies.
If you're into shortwave monitoring and dedicated to it, a communications receiver is what you'd more than likely have. Some devices can be under $100 and be traditional "shortwave radios" with AM/FM and shortwave capability, but some of the much better hardware in this class is in the several thousand dollar range so, again, they're for the more serious monitor or whoever happens to need such hardware. Government agencies would use such types of devices in their monitoring duties too.
SDR = Software Defined Radio or Receiver is in its most basic sense of the concept a radio tuner designed to be controlled and utilized using software. Now, the difference with something like a scanner which has a firmware that controls it - firmware isn't something that really can be altered, of course a firmware update can provide new features or fix bugs, even extend capabilities already present in the device but in general it's a "fixed" thing meaning it doesn't change and you can't really alter it yourself. SDR, on the other hand, is incredibly flexible in what's possible and there really are no limits except those related to people creating the software to accomplish the things they want to do. The sky's the limit, basically, and as long as someone with the coding and development skills is at work, they can make most anything possible.
The field of SDR as well as the general concept in the radio monitoring community has really exploded in the past 3-4 years for a variety of reasons: the cost of such hardware has been steadily dropping because it's easier to develop nowadays, people are more talented with the code needed to control such hardware, and other reasons. But the biggest reason overall has to be the discovery a few years ago by someone that those "cheap USB TV tuners" with some driver modifications could be used as wideband radio receivers. Originally designed to be used with the European (and other countries in that region) DVB standard, the Digital Video Broadcast system, which was their digital TV system (again, this info is off the top of my head so I might not be 100% on the money for every specific detail). As I understand it what happened is the European community or whoever set the idea of using DVB-T for their television transmissions and before it became a solid long term solution they ended up choosing an entirely different system that wasn't compatible.
So one benefit was there were thousands if not hundreds of thousands of those "cheap USB TV tuners" manufactured and before they really got useful the standard changed and they effectively became useless devices that couldn't even be used to tune the newer digital TV system over in the European region. Here in the US we use a system know as ATSC (Advanced Television Systems Committee) and those sticks were never compatible with our new digital TV system at all anyway.
When someone discovered with driver mods that you could use them as wideband radio receivers, that was practically a paradigm shift in how things were now going to work. Think of it like this:
For decade upon decade, the radio monitoring community and hobbyists and Ham radio operators had always listened - literally listened - to the communications they were monitoring and that was that. Now, with the introduction of computers and now those "cheap USB TV tuners" as well as other higher end SDR hardware like HackRF, BladeRF, units from Ettus and other companies and so on, allowed us to not only hear the same things we've always been able to hear but now with the introduction of the software needed to control SDR hardware we've now added a visual capability - we don't just listen anymore to a frequency at a time, we can "see" the spectrum of activity inside a given window of bandwidth.
In the good old days you'd tune in a frequency, sometimes considered to be a "channel," and monitor it. If you had a device with memories of some kind you could program in some frequencies and the device - a scanner, if you will - would then scan the programmed frequencies and stop when a transmission was heard (tripped the squelch), and when it went back to silence it would either immediately begin scanning again or wait a pre-programmed amount of time for the delay (like 2 seconds was a very common amount) so any kind of reply to a communication might be heard before scanning resumed. Basically the best you could do was one channel or frequency at a time, unless you owned multiple physical scanners or receivers so you could do more than one at at time.
Now, with SDR, you can literally monitor several frequencies at the same time using just one SDR device - I've personally had SDR-Radio (a most excellent software application) running with just one of those "cheap USB TV tuners" aka RTL sticks and been able to monitor/record six different frequencies at the same time, simultaneously.. Not too bad for a $10 device with free software, eh? The moment I realized this, that I could listen to several frequencies at the same time as long as they're inside the "window" of bandwidth of the given SDR hardware I'm using just blew my mind, it was a defining moment in my monitoring hobby, right up there with the moment about 30 years ago when I got my first trunk tracking handheld scanner.
Just like trunk tracking did for plain old analog monitoring duties, SDR for me changed everything for me all over again.
So yeah, a long post but I hope it covers some of the bases. Just as with anything, you can go from the low end to the high end with respect to the hardware:
- scanners can be on the low end with not many capabilities other than some memories, the basic AM and FM narrow band reception, a small display with not much info, an antenna that works but not that well, and so on up to the high end scanners which are several hundred bucks but have all the bells and whistles you might hope for
- receivers can be something as simple as a budget low end AM/FM radio (literally) or one that might add some shortwave or weather band capability and then on up to the massive desktop class communications receivers in the several thousand dollar range and so on
And then there's SDR which also can also go from the low end with the "cheap USB TV tuners" which are incredible considering they're obsolete in most respects for their intended design purpose (the DVB-T system is practically obsolete nowadays) but miraculously they are extremely capable in our hobby of monitoring radio communications. Consider this for a second:
- the best scanners that Uniden and GRE/Whistler manufacture not only today but over the past few years typically cannot monitor - and by monitor I mean receive and decode into a voice signal that you can understand - some particular digital modes of communication (DMR/NXDN/etc). They can handle the most popular methods (analog and P25 Phase I and II) but that's their limitation, at least for now. A lot of people are hoping that Uniden and Whistler (the new owners of all the GRE hardware and patents as I understand it) will add DMR decoding capability as well as NXDN because those digital formats are gaining popularity with extreme haste worldwide. Even Hams now use DMR in many places, and they've used P25 Phase I for years now.
The best communications receivers on the market today, some in the $8000 range and higher, can't do that either meaning decode the newer digital formats into a voice coming from your speaker or headset that you can understand. They have tons of capabilities, but they can't monitor and decode those.
But with a $10 stick and some free software like SDR# aka SDRSharp and DSD+ and a computer (which most people tend to have nowadays), even a sub-$100 tablet device running the desktop version of Windows (7, 8/8.1, or even 10) you can listen to pretty much anything, even those newer digital formats that nothing else is capable of monitoring properly. And not only that, but you can also listen to several frequencies simultaneously (if you must) or record them in real-time to separate audio files and go back and listen to them later whenever.
How that's for a shift in how things are changing?
I have to clarify the multi-frequency thing before I finish this post: with an SDR device of whatever kind, the device will be capable of a given amount of bandwidth meaning the "window" of frequencies it can see or receive at one time. The low end RTL sticks, the most commonly used devices these days, have a maximum useful bandwidth of about 2.4 MHz - that means when you use one you can set the bandwidth to 2.4 MHz and the spectrum display window of your SDR software will show you 2.4 MHz of spectrum from left to right, so you'd see something like 850.0000 MHz as the far left side and 852.4000 as the far right side - you will "see" everything that's going on in that chunk of bandwidth. Each transmission that shows up as a peak on the spectrum is a signal, and the stick is "seeing" all of that activity in real-time - you can even record all of it, the entire 2.4 MHz at one time.
That's vastly different from the good old days of just one frequency at a time, even on the best hardware.
As I stated earlier, I consider SDR a paradigm shift in our monitoring hobby, akin to the time long ago when trunk tracking became a reality for those of us that are into that sort of thing. I've never been big into shortwave personally but obviously a great number of people in our hobby are, that may change for me in the near future since I'm considering an SDR device (SDRPlay) that comes with native support for HF aka shortwave band reception all the way down to 100 kHz.
It's a great time for our hobby, certainly.
I'm gonna shut up now, hopefully some of this info is useful to you. I'm guessing you're probably getting started with things because of your post count so, welcome to the community here at RR and if you have questions, don't hesitate to ask. There's a ton of helpful folks around here and the majority of them probably have vastly more experience than I do with a lot more respects too, I'm still primarily a hobbyist overall and always will be but some members here are working professionals in radio and telecommunications for many decades on top of being Ham radio operators too.
Have fun, always...
ps
With respect to receivers being big and only for the desktop, I wanted to add that their are some very capabile communications receivers from AOR and Icom and a few other companies that are in the traditional handheld form factor. The classic AOR AR1000 and the classic Icom IC-R6 are just two examples of such handheld hardware. While they can't do everything the desktop class models are capable of, they themselves are incredibly useful devices. So yes in some respects because they have memories and can "scan" the memories they could be considered to be scanners too but, AOR and Icom wouldn't like it very much to call their products "scanners."
Scanner = using the most common usage of the term would be a device which is used to scan (literally) frequencies that are either programmed in or scanned manually looking for "new" ones you may have not heard anything on previously. I would hazard to say that using the term "scanner" means something that you'd using to monitor police, fire, EMS, and other things in your local area because again that's the most common usage of the term. "Police scanner" is easy to understand and if you went into an electronics shop most anywhere and asked for that would be immediately understood. They traditionally come in two main form factors: handhelds and mobile/base models. Handhelds are obviously small and portable, while the mobile devices are designed to be used in vehicles but can easily just be used at home or wherever as a "base" station scanner just as easily. The basic difference is a handheld is extremely portable and self-contained where a mobile/base usually require a dedicated power supply of some kind and a dedicated attached antenna that are not part of the device itself as a handheld happens to be.
A scanner of such type is limited to the hardware it's designed with so in effect you're "stuck" with whatever the hardware maker chose to allow the hardware to be able to monitor - what I mean by this is if you have a purely analog scanner which can only receive analog transmissions (basically the concept of an AM or FM radio for listening to audio/music) then that's pretty much all you're going to be able to monitor. Newer scanners can do more by having extra circuitry onboard to receive digital communications - the term there is a bit tough to grasp for some because in effect they're analog transmissions in reality, they're just broadcasting content in the audible spectrum that is then decoded similar to how data is sent using an old school dialup modem on a computer. If you were to listen in on the actual communications used by dialup modems you'd hear that familiar screeching audio sound that modulates based on the particular protocol in use. A very old 300 baud modem would sound one way, a 2400 another, a 14.4 model yet another, 28.8, 56K etc and so on.
Digital communications are analog transmissions of a modulated audio signal (that you can hear, there are dozens of them and you can get some idea of what you'd be picking up at this page which is a great source of info on tracking down those odd blips, bleeps, and screeches you'd hear on various frequencies using a scanner or receiver or SDR hardware.
Some digital comms are very popular nowadays like APCO P25 Phase I which is a worldwide standard form of digital comms and has been for some time. It's been improved upon with Phase II but Phase II decoding is still relatively new and while a few handheld models exist from Uniden and GRE/Whistler, there are other modes like DMR aka MOTOTRBO, NexEdge aka NXDN, and several others that simply cannot be monitored with any modern scanner. Having said that, if you happen to have a good quality scanner you can probably work a setup that feeds the signal received by the scanner to a computer which can run software to decode those other digital modes, with DSD+ aka DSDPlus being the favorite right now. It's in active development and a fantastic piece of software that's not too difficult to figure out for most anyone.
Receiver = using the most common usage of the term would mean one of the larger dedicated pieces of hardware from brand name companies like AOR, Icom, Yaesu, Kenwood, and so on. They're primarily designed for shortwave reception (don't hate on me for saying this, please, because it's true for the most part) but some models, especially the high end ones from Icom and AOR, can handle frequencies from the lowest of the lows to the highest of the highs meaning well into the gigahertz range without breaking a sweat. They're not "scanners" in that sense, they are very narrow purpose devices that are traditionally manually operated (with a big tuning dial and a frequency display of various kinds), as well as having the ability to be transceivers as well in some cases so they not only receive but allow for transmission on given frequencies.
If you're into shortwave monitoring and dedicated to it, a communications receiver is what you'd more than likely have. Some devices can be under $100 and be traditional "shortwave radios" with AM/FM and shortwave capability, but some of the much better hardware in this class is in the several thousand dollar range so, again, they're for the more serious monitor or whoever happens to need such hardware. Government agencies would use such types of devices in their monitoring duties too.
SDR = Software Defined Radio or Receiver is in its most basic sense of the concept a radio tuner designed to be controlled and utilized using software. Now, the difference with something like a scanner which has a firmware that controls it - firmware isn't something that really can be altered, of course a firmware update can provide new features or fix bugs, even extend capabilities already present in the device but in general it's a "fixed" thing meaning it doesn't change and you can't really alter it yourself. SDR, on the other hand, is incredibly flexible in what's possible and there really are no limits except those related to people creating the software to accomplish the things they want to do. The sky's the limit, basically, and as long as someone with the coding and development skills is at work, they can make most anything possible.
The field of SDR as well as the general concept in the radio monitoring community has really exploded in the past 3-4 years for a variety of reasons: the cost of such hardware has been steadily dropping because it's easier to develop nowadays, people are more talented with the code needed to control such hardware, and other reasons. But the biggest reason overall has to be the discovery a few years ago by someone that those "cheap USB TV tuners" with some driver modifications could be used as wideband radio receivers. Originally designed to be used with the European (and other countries in that region) DVB standard, the Digital Video Broadcast system, which was their digital TV system (again, this info is off the top of my head so I might not be 100% on the money for every specific detail). As I understand it what happened is the European community or whoever set the idea of using DVB-T for their television transmissions and before it became a solid long term solution they ended up choosing an entirely different system that wasn't compatible.
So one benefit was there were thousands if not hundreds of thousands of those "cheap USB TV tuners" manufactured and before they really got useful the standard changed and they effectively became useless devices that couldn't even be used to tune the newer digital TV system over in the European region. Here in the US we use a system know as ATSC (Advanced Television Systems Committee) and those sticks were never compatible with our new digital TV system at all anyway.
When someone discovered with driver mods that you could use them as wideband radio receivers, that was practically a paradigm shift in how things were now going to work. Think of it like this:
For decade upon decade, the radio monitoring community and hobbyists and Ham radio operators had always listened - literally listened - to the communications they were monitoring and that was that. Now, with the introduction of computers and now those "cheap USB TV tuners" as well as other higher end SDR hardware like HackRF, BladeRF, units from Ettus and other companies and so on, allowed us to not only hear the same things we've always been able to hear but now with the introduction of the software needed to control SDR hardware we've now added a visual capability - we don't just listen anymore to a frequency at a time, we can "see" the spectrum of activity inside a given window of bandwidth.
In the good old days you'd tune in a frequency, sometimes considered to be a "channel," and monitor it. If you had a device with memories of some kind you could program in some frequencies and the device - a scanner, if you will - would then scan the programmed frequencies and stop when a transmission was heard (tripped the squelch), and when it went back to silence it would either immediately begin scanning again or wait a pre-programmed amount of time for the delay (like 2 seconds was a very common amount) so any kind of reply to a communication might be heard before scanning resumed. Basically the best you could do was one channel or frequency at a time, unless you owned multiple physical scanners or receivers so you could do more than one at at time.
Now, with SDR, you can literally monitor several frequencies at the same time using just one SDR device - I've personally had SDR-Radio (a most excellent software application) running with just one of those "cheap USB TV tuners" aka RTL sticks and been able to monitor/record six different frequencies at the same time, simultaneously.. Not too bad for a $10 device with free software, eh?
The moment I realized this, that I could listen to several frequencies at the same time as long as they're inside the "window" of bandwidth of the given SDR hardware I'm using just blew my mind, it was a defining moment in my monitoring hobby, right up there with the moment about 30 years ago when I got my first trunk tracking handheld scanner.Just like trunk tracking did for plain old analog monitoring duties, SDR for me changed everything for me all over again.
So yeah, a long post but I hope it covers some of the bases. Just as with anything, you can go from the low end to the high end with respect to the hardware:
- scanners can be on the low end with not many capabilities other than some memories, the basic AM and FM narrow band reception, a small display with not much info, an antenna that works but not that well, and so on up to the high end scanners which are several hundred bucks but have all the bells and whistles you might hope for
- receivers can be something as simple as a budget low end AM/FM radio (literally) or one that might add some shortwave or weather band capability and then on up to the massive desktop class communications receivers in the several thousand dollar range and so on
And then there's SDR which also can also go from the low end with the "cheap USB TV tuners" which are incredible considering they're obsolete in most respects for their intended design purpose (the DVB-T system is practically obsolete nowadays) but miraculously they are extremely capable in our hobby of monitoring radio communications. Consider this for a second:
- the best scanners that Uniden and GRE/Whistler manufacture not only today but over the past few years typically cannot monitor - and by monitor I mean receive and decode into a voice signal that you can understand - some particular digital modes of communication (DMR/NXDN/etc). They can handle the most popular methods (analog and P25 Phase I and II) but that's their limitation, at least for now. A lot of people are hoping that Uniden and Whistler (the new owners of all the GRE hardware and patents as I understand it) will add DMR decoding capability as well as NXDN because those digital formats are gaining popularity with extreme haste worldwide. Even Hams now use DMR in many places, and they've used P25 Phase I for years now.
The best communications receivers on the market today, some in the $8000 range and higher, can't do that either meaning decode the newer digital formats into a voice coming from your speaker or headset that you can understand. They have tons of capabilities, but they can't monitor and decode those.
But with a $10 stick and some free software like SDR# aka SDRSharp and DSD+ and a computer (which most people tend to have nowadays), even a sub-$100 tablet device running the desktop version of Windows (7, 8/8.1, or even 10) you can listen to pretty much anything, even those newer digital formats that nothing else is capable of monitoring properly. And not only that, but you can also listen to several frequencies simultaneously (if you must) or record them in real-time to separate audio files and go back and listen to them later whenever.
How that's for a shift in how things are changing?
I have to clarify the multi-frequency thing before I finish this post: with an SDR device of whatever kind, the device will be capable of a given amount of bandwidth meaning the "window" of frequencies it can see or receive at one time. The low end RTL sticks, the most commonly used devices these days, have a maximum useful bandwidth of about 2.4 MHz - that means when you use one you can set the bandwidth to 2.4 MHz and the spectrum display window of your SDR software will show you 2.4 MHz of spectrum from left to right, so you'd see something like 850.0000 MHz as the far left side and 852.4000 as the far right side - you will "see" everything that's going on in that chunk of bandwidth. Each transmission that shows up as a peak on the spectrum is a signal, and the stick is "seeing" all of that activity in real-time - you can even record all of it, the entire 2.4 MHz at one time.
That's vastly different from the good old days of just one frequency at a time, even on the best hardware.
As I stated earlier, I consider SDR a paradigm shift in our monitoring hobby, akin to the time long ago when trunk tracking became a reality for those of us that are into that sort of thing. I've never been big into shortwave personally but obviously a great number of people in our hobby are, that may change for me in the near future since I'm considering an SDR device (SDRPlay) that comes with native support for HF aka shortwave band reception all the way down to 100 kHz.
It's a great time for our hobby, certainly.
I'm gonna shut up now, hopefully some of this info is useful to you. I'm guessing you're probably getting started with things because of your post count so, welcome to the community here at RR and if you have questions, don't hesitate to ask. There's a ton of helpful folks around here and the majority of them probably have vastly more experience than I do with a lot more respects too, I'm still primarily a hobbyist overall and always will be but some members here are working professionals in radio and telecommunications for many decades on top of being Ham radio operators too.
Have fun, always...
ps
With respect to receivers being big and only for the desktop, I wanted to add that their are some very capabile communications receivers from AOR and Icom and a few other companies that are in the traditional handheld form factor. The classic AOR AR1000 and the classic Icom IC-R6 are just two examples of such handheld hardware. While they can't do everything the desktop class models are capable of, they themselves are incredibly useful devices. So yes in some respects because they have memories and can "scan" the memories they could be considered to be scanners too but, AOR and Icom wouldn't like it very much to call their products "scanners."
Last edited:
THANK YOU! That was EXACTLY what I hoped someone would respond!
I recently purchased an HP-2 but found that it did not have the Close Call that seems to be the bee's knees. In searching for more information on this I ran into all the others and besides the price it all kind of sounded the same. You answered all the questions I had!
Now I know what I need to satisfy the geek tinkerer in me.. an SDR. I will go read the forums and see which seems best for newbies.
Thanks again for an awesome post!!
I recently purchased an HP-2 but found that it did not have the Close Call that seems to be the bee's knees. In searching for more information on this I ran into all the others and besides the price it all kind of sounded the same. You answered all the questions I had!
Now I know what I need to satisfy the geek tinkerer in me.. an SDR. I will go read the forums and see which seems best for newbies.
Thanks again for an awesome post!!
br0adband
Member
Right now the best in terms of effectiveness, sensitivity, and of course price is an RTL-based stick (meaning it uses the Realtek RTL2832 chip for USB connectivity to the computer - the actual tuner on the stick is a Rafael Microelectronics R820T or R820T2 which I'll explain here in a moment) and you can find them literally for $10 or less these days from a multitude of suppliers.
The original tuner chip, the R820T, is still quite capable and what really started the movement towards SDR because of a) the cheap price (RTL sticks were originally in the $50+ range but have come down considerably over the past 2 years) and b) the ease of installation using the Zadig drivers (that's my opinion, basically). There was and still is another USB stick brand/type available but it's in rare quantity nowadays and that happens to be devices based on the Elonics E4000 tuner which has a much wider frequency range - from about 52 to 2200 MHz - compared to the R820T/T2 sticks which cover about 24 to 1800 MHz reasonably well but there have been reports that above 1100 MHz they have issues with sensitivity and noise and some other problems.
I've never bothered to monitor or even try to find something to monitor over 950 MHz myself. I know the ADS-B community is crazy about 1090 MHz because that's the frequency where airplanes of all kinds transmit their identifiers so people monitor that stuff and send the data into websites like FlightRadar24.com where you can actually watch flights in real-time from around the world. It's pretty cool nowadays to be able to do such things, and it's not just because of SDR that this is possible obviously but it damned sure makes things easier - you could monitor such broadcasts with a typical scanner or receiver, but having that computer interface is where the magic really happens. And yes, you can interface scanners and receivers to a PC nowadays but, SDR is a whole new ballgame, really.
At this point my recommendation - if this will be your first SDR device - would be those sold by RTL-SDR.com and I will make disclaimer here: I am not affiliated with them in any respects, I'm just going on the info I've found online based on a particular aspect of those sticks they're selling. That one particular aspect is the temperature controlled oscillator or TCXO which makes sure the stick stays on frequency and has effectively no drift at all. The side effect of the "cheap USB TV tuner" aspect of these devices tends to be that when they warm up when powered up is the hardware builds up a temperature and the original R820T based hardware used a crystal onboard that would change its properties when the temp rose. What that meant is that each stick would have a particular offset known basically as ppm or parts per million where you'd have to figure out what the optimal ppm for any given stick is/was based on the normal operating temp. If you don't "calibrate" your stick to the ppm it happens to exhibit then it'll never be exactly or even really close to being on frequency.
Anyway, not to make it too complicated but the newer RTL sticks that are available are a little more costly, like $24-30 on average, but they improve on the original R820T design in three respects:
1) They have an improved tuner, the R820T2, which has slightly better sensitivity overall and a lower noise floor aka higher SNR overall compared to the original R820T based models
2) Some of them, but not all of them, will have the 1 PPM TCXO I just mentioned so you have to make sure you're getting one that does actually have that so you won't end up worrying about being off frequency more often than not. Even with a known ppm value for a given stick, it can and does still drift on and off frequency but the newer versions with the R820T2 + the TCXO pretty much ensure you set it and forget it
3) Newer sticks tend to have SMA connectors on them for the antenna which is a vast improvement over the MCX style connector the older sticks came with. SMA is a more widespread antenna connector these days but be aware of the male/female aspects - I know a lot of Wi-Fi antenna hardware uses SMA connectors as well but I believe they're reverse SMA compared to the type of connectors used in the radio industry. I'm not 100% certain on that since I don't own any radio hardware with SMA connectors so, make sure to check on that aspect if needed.
So, for $25 or so depending on shipping charges (figure $30 to $35) you'd be getting a much better stick in several respects plus the newer ones tend to come with not one antenna but two, especially the ones sold by RTL-SDR.com. The original RTL sticks like the ones I have from NooElec (a great company, really) came with the original cheap as hell stick antenna and it was for most intents and purposes useless. The original RTL sticks also had that MCX connector on a very short and very cheap piece of cable attached to that cheap antenna. It did work to some degree but it wasn't any good as a wideband antenna at all.
The newer sticks come with two telescopic whips so you can adjust them as required but the point being that using the SMA connectors makes it much easier to get better antenna hardware without the need to have a bunch of adapters around for mating the cables to the hardware which just causes more loss in the line that nobody wants at all anyway.
But anyway, glad to see you're interested and it's a lot of fun to get involved. It's a huge difference from the good old scanning methods, definitely, and a more than welcome addition to our hobby.
Also, since you're getting your feet wet so to speak, don't think that my recommendation to "go cheap" to start with means that the higher end hardware isn't an option. The SDRPlay at $150, Airspy at $199, and HackRF and other devices at $399 and higher are there for the buying if you're so inclined. I merely stated the basics to get you rolling - most people would want to get involved with minimum expense to see if they want to get even more involved so, this is the best way to do it. The original RTL sticks are still available and they still work fine, but the newer R820T2 based models with the TCXO are what you should look at, definitely. You don't have to get them from the company I mentioned, but that's the cheapest price I've found for one that has the R820T2, the TCXO, and the two antennas included hence me mentioning it.
ps
Apparently NooElec has a sale right now (not sure when it'll end) with an R820T2 + TXCO for $27.95 so it's an option as well and it has a 0.5 ppm rating so it technically is better but just one antenna BUT the downside to this one is it still uses the old style MCX antenna connector so, keep that in mind - the one above from RTL-SDR.com would be my choice and recommendation for that reason alone (having the SMA connector):
http://www.nooelec.com/store/sdr/nesdr-mini-2-plus.html
I purchased both the R820T sticks I own from NooElec almost 2 years ago now and never had an issue with either of them. In the long run a lot of the companies selling such hardware are just resellers getting their devices from a manufacturer somewhere in China (Japan in the case of this one from NooElec) or wherever so, even if you bought from one or the other chances are the hardware itself is actually the same (meaning exactly the same from the same factory, etc) and just branded with the reseller's name, just so you know.
The original tuner chip, the R820T, is still quite capable and what really started the movement towards SDR because of a) the cheap price (RTL sticks were originally in the $50+ range but have come down considerably over the past 2 years) and b) the ease of installation using the Zadig drivers (that's my opinion, basically). There was and still is another USB stick brand/type available but it's in rare quantity nowadays and that happens to be devices based on the Elonics E4000 tuner which has a much wider frequency range - from about 52 to 2200 MHz - compared to the R820T/T2 sticks which cover about 24 to 1800 MHz reasonably well but there have been reports that above 1100 MHz they have issues with sensitivity and noise and some other problems.
I've never bothered to monitor or even try to find something to monitor over 950 MHz myself. I know the ADS-B community is crazy about 1090 MHz because that's the frequency where airplanes of all kinds transmit their identifiers so people monitor that stuff and send the data into websites like FlightRadar24.com where you can actually watch flights in real-time from around the world. It's pretty cool nowadays to be able to do such things, and it's not just because of SDR that this is possible obviously but it damned sure makes things easier - you could monitor such broadcasts with a typical scanner or receiver, but having that computer interface is where the magic really happens. And yes, you can interface scanners and receivers to a PC nowadays but, SDR is a whole new ballgame, really.
At this point my recommendation - if this will be your first SDR device - would be those sold by RTL-SDR.com and I will make disclaimer here: I am not affiliated with them in any respects, I'm just going on the info I've found online based on a particular aspect of those sticks they're selling. That one particular aspect is the temperature controlled oscillator or TCXO which makes sure the stick stays on frequency and has effectively no drift at all. The side effect of the "cheap USB TV tuner" aspect of these devices tends to be that when they warm up when powered up is the hardware builds up a temperature and the original R820T based hardware used a crystal onboard that would change its properties when the temp rose. What that meant is that each stick would have a particular offset known basically as ppm or parts per million where you'd have to figure out what the optimal ppm for any given stick is/was based on the normal operating temp. If you don't "calibrate" your stick to the ppm it happens to exhibit then it'll never be exactly or even really close to being on frequency.
Anyway, not to make it too complicated but the newer RTL sticks that are available are a little more costly, like $24-30 on average, but they improve on the original R820T design in three respects:
1) They have an improved tuner, the R820T2, which has slightly better sensitivity overall and a lower noise floor aka higher SNR overall compared to the original R820T based models
2) Some of them, but not all of them, will have the 1 PPM TCXO I just mentioned so you have to make sure you're getting one that does actually have that so you won't end up worrying about being off frequency more often than not. Even with a known ppm value for a given stick, it can and does still drift on and off frequency but the newer versions with the R820T2 + the TCXO pretty much ensure you set it and forget it
3) Newer sticks tend to have SMA connectors on them for the antenna which is a vast improvement over the MCX style connector the older sticks came with. SMA is a more widespread antenna connector these days but be aware of the male/female aspects - I know a lot of Wi-Fi antenna hardware uses SMA connectors as well but I believe they're reverse SMA compared to the type of connectors used in the radio industry. I'm not 100% certain on that since I don't own any radio hardware with SMA connectors so, make sure to check on that aspect if needed.
So, for $25 or so depending on shipping charges (figure $30 to $35) you'd be getting a much better stick in several respects plus the newer ones tend to come with not one antenna but two, especially the ones sold by RTL-SDR.com. The original RTL sticks like the ones I have from NooElec (a great company, really) came with the original cheap as hell stick antenna and it was for most intents and purposes useless. The original RTL sticks also had that MCX connector on a very short and very cheap piece of cable attached to that cheap antenna. It did work to some degree but it wasn't any good as a wideband antenna at all.
The newer sticks come with two telescopic whips so you can adjust them as required but the point being that using the SMA connectors makes it much easier to get better antenna hardware without the need to have a bunch of adapters around for mating the cables to the hardware which just causes more loss in the line that nobody wants at all anyway.
But anyway, glad to see you're interested and it's a lot of fun to get involved. It's a huge difference from the good old scanning methods, definitely, and a more than welcome addition to our hobby.
Also, since you're getting your feet wet so to speak, don't think that my recommendation to "go cheap" to start with means that the higher end hardware isn't an option. The SDRPlay at $150, Airspy at $199, and HackRF and other devices at $399 and higher are there for the buying if you're so inclined. I merely stated the basics to get you rolling - most people would want to get involved with minimum expense to see if they want to get even more involved so, this is the best way to do it. The original RTL sticks are still available and they still work fine, but the newer R820T2 based models with the TCXO are what you should look at, definitely. You don't have to get them from the company I mentioned, but that's the cheapest price I've found for one that has the R820T2, the TCXO, and the two antennas included hence me mentioning it.
ps
Apparently NooElec has a sale right now (not sure when it'll end) with an R820T2 + TXCO for $27.95 so it's an option as well and it has a 0.5 ppm rating so it technically is better but just one antenna BUT the downside to this one is it still uses the old style MCX antenna connector so, keep that in mind - the one above from RTL-SDR.com would be my choice and recommendation for that reason alone (having the SMA connector):
http://www.nooelec.com/store/sdr/nesdr-mini-2-plus.html
I purchased both the R820T sticks I own from NooElec almost 2 years ago now and never had an issue with either of them. In the long run a lot of the companies selling such hardware are just resellers getting their devices from a manufacturer somewhere in China (Japan in the case of this one from NooElec) or wherever so, even if you bought from one or the other chances are the hardware itself is actually the same (meaning exactly the same from the same factory, etc) and just branded with the reseller's name, just so you know.
Last edited:
br0adband
Member
If you want to decode APCO P25 Phase I using SDR hardware (pretty much anything on the market today from the low end RTL sticks to the higher end SDR devices like HackRF and even more expensive ones) you have two options and both of these are Windows only solutions, I'll speak of a Linux solution later in the post):
- DSD which is the original Digital Speech Decoder (by definition, hence the name DSD) but from what I can tell it is not under serious active development - the version that is available at present I think is either 1.6 or 1.7 and it can decode P25 Phase I without issues. In my limited experience of using it in the past I do recall it did produce great sounding audio decodes so it's a tool for consideration if needed
- DSD+ aka DSDPlus which is a completely different digital speech decoder (there was some discussion of it being a fork of DSD in the past but I think that was quashed once and for all) that is under heavy active development, gets new features and capabilities added almost with each version that's published (there is a public version that's free and a development version know as "fast lane" which is covered by a donation made to the developers, it's like $10 for a year iirc) and you get the latest updates as soon as they're available. The fast lane version currently as I understand it supports trunking on DMR and NXDN systems but I'm not sure about anything else (I'm not part of the fast lane supporters yet, but soon)
That's for P25 Phase I, so regarding P25 Phase II there is only one computer based solution at this time and that's with OP25 which is a Linux-native tool based off GNURadio and it's a lot more difficult to set up and get functional. It's not impossible, mind you, just a lot more difficult and since it's Linux native a lot of people may not be willing to go that far to make use of OP25. It's capable, it gets the job done, it handles P25 Phase I and Phase II without many issues at all, but again it's a process to get it working correctly. One caveat: OP25 is very CPU intensive when it's running. On my i5 CPU which runs at 2.8 GHz (two cores, four threads) it will regularly show max CPU usage on one or two cores - mind you two of the four threads are virtual ones using hyperthreading - during a P25 Phase II decode. It's not the most efficient decoder but for P25 Phase II it is at this moment the only one available.
It also doesn't work well inside a virtual machine if you're interested in toying around with it in that respect. Many people, myself included, have made many attempts to get OP25 functional in a virtual machine (using Linux as a guest OS on top of a Windows host OS, not sure if any Mac owners using OSX have made any attempts to do this). I said it doesn't work well, meaning that it does work once everything is installed, compiled, and set up - the resulting audio it produces is nothing but chopped stuttered and completely unintelligible even on the latest and most powerful computer hardware.
Basically, if you want to use decode Phase II on a computer, it requires Linux and OP25 installed (which also requires GNURadio too but the pybombs installation script can do all of it automagically for you without much fuss).
So to summarize:
It is completely possible to monitor a P25 Phase II system on a PC using an SDR device these days, it just requires time, patience, and effort to make it possible but it requires Linux + OP25.
Phase I can be easily monitored using DSD or DSD+ (my recommendation is DSD+, however) on Windows - I think in the past there was a fork of the original DSD for Linux but I'm not 100% certain on that. DSD+ is a Windows only tool.
As for doing any of this on OSX, I don't know of any working P25 Phase I or Phase II decoders available - I say that because you're posting from an iPad so I'm making a stupid assumption most likely.
Apologies if my fast scan of Br0adband's detailed and useful replies didn't pick this up in his posts, but....
If you are getting into SDR with the RTL-stick USB receiver devices, ensure you are facile with computers. And I mean able to install / update / remove drivers in at least any version of Windows you are using, but also Linux because some of the programs you may choose to run with your SDR may require it. If you want a neat, single box, connect power and antenna.... and you're off and scanning... the RTL sticks are not for you. Typically, many devices (RTL stick, computer, external antenna, several types of software) are needed to make it all work. If this is your comfort zone, then you will love it. If messing with computers and software is not for you.... steer clear. To get a sense of the kinds of challenges people face when setting up their computer-based RTL-SDRs, go over to the Software Defined Radio Forum here on RR and read some of the posts that have "How to", "I can't...", "Won't install...", "Is there a way to...." in the Subject line.
If you're looking for a scanning receiver for mobile or portable use and plan to use an RTL SDR to accomplish that.... you'll be in a DIY mode with lots of cables and connectors between the various boxes and devices you'll need to assemble. And the end result may work, but not be ready for "mobile in motion" usage.
As with all things that begin with "experimenter specials", this will change for the better over time. And right now there are some things that can be done at very low cost only with RTL SDRs. But it's not yet an all-in-one off the shelf plug and play setup.
If you are getting into SDR with the RTL-stick USB receiver devices, ensure you are facile with computers. And I mean able to install / update / remove drivers in at least any version of Windows you are using, but also Linux because some of the programs you may choose to run with your SDR may require it. If you want a neat, single box, connect power and antenna.... and you're off and scanning... the RTL sticks are not for you. Typically, many devices (RTL stick, computer, external antenna, several types of software) are needed to make it all work. If this is your comfort zone, then you will love it. If messing with computers and software is not for you.... steer clear. To get a sense of the kinds of challenges people face when setting up their computer-based RTL-SDRs, go over to the Software Defined Radio Forum here on RR and read some of the posts that have "How to", "I can't...", "Won't install...", "Is there a way to...." in the Subject line.
If you're looking for a scanning receiver for mobile or portable use and plan to use an RTL SDR to accomplish that.... you'll be in a DIY mode with lots of cables and connectors between the various boxes and devices you'll need to assemble. And the end result may work, but not be ready for "mobile in motion" usage.
As with all things that begin with "experimenter specials", this will change for the better over time. And right now there are some things that can be done at very low cost only with RTL SDRs. But it's not yet an all-in-one off the shelf plug and play setup.
br0adband
Member
I'll agree with some parts of what popnokick just posted but not all of it, obviously (that would be too easy).
I won't go so far as to say it's not possible, even for someone not that experienced with computers probably because I've been teaching people about computers and consumer electronics for many decades now so I don't go into it with the "if you can't install a driver don't even bother..." angle. Sorry, that didn't come out like I had intended but I think the point is being made, it's not a slam against you, popnokick. The OP did put his post here in the New User / Getting Started subforum so...
It's not plug and play, nope, that much I totally agree with, and I also agree with the idea that some people think that when they've got it working it'll be like having a scanner but on a computer 'cause it sure as hell isn't that either (although it could be and I still wonder why someone hasn't done it up proper I suppose - I lack the necessary talent as well as the creativity for that kind of coding, sadly).
But in the long run, it's another facet of this hobby and since things are moving towards computer aided or controlled or even software defined monitoring then I'm happy to help whenever I can even if I have to write a damned step by step guide for a total newb to this stuff.
I won't go so far as to say it's not possible, even for someone not that experienced with computers probably because I've been teaching people about computers and consumer electronics for many decades now so I don't go into it with the "if you can't install a driver don't even bother..." angle. Sorry, that didn't come out like I had intended but I think the point is being made, it's not a slam against you, popnokick. The OP did put his post here in the New User / Getting Started subforum so...
It's not plug and play, nope, that much I totally agree with, and I also agree with the idea that some people think that when they've got it working it'll be like having a scanner but on a computer 'cause it sure as hell isn't that either (although it could be and I still wonder why someone hasn't done it up proper I suppose - I lack the necessary talent as well as the creativity for that kind of coding, sadly).
But in the long run, it's another facet of this hobby and since things are moving towards computer aided or controlled or even software defined monitoring then I'm happy to help whenever I can even if I have to write a damned step by step guide for a total newb to this stuff.
I really appreciate the posts and am thoroughly looking forward to getting into the SDRs. The technical play room is what I am looking for without a huge investment. I spent the big bucks on the HP-2 and it was almost a let down compared to my prior scanner, a Pro-95, in regards to 'play-ability'. But, any antennas I put up will be usable to both with the SMA connectors.
I spent 20+ in development and support of Windows environments so drivers, resources, port settings, are all old hat. It should be fun.
I spent 20+ in development and support of Windows environments so drivers, resources, port settings, are all old hat. It should be fun.
br0adband
Member
Yah, you'll be fine. With the device in hand, if it takes you more than say 5 mins to plug it in, install the Zadig drivers (there will be two devices listed, the Interface 0 is the actual RTL tuner, Interface 1 is the infrared controller on-board because by design they're TV tuners and yes you install the same driver for both interfaces), download and extract the SDR# archive from Airspy.com, run the installer batch file so it puts the rltsdr.dll in the right place and fire it up, click the gear icon, make some adjustments, ensure you've got the RTL (USB) device chosen as the source, then hit the Play button and run with it.
Yes, a lot of folks do find it somewhat difficult to get things working but it shouldn't take more than about 5 minutes to get started. Now, where they choose to go from that point on can be much more difficult because a lot of newcomers to SDR just get frustrated with the fact that it's not a scanner like they're used to having which can be or probably was already programmed from the gitgo and it's easy to use since it's ready to go out of the box most times. Having said that, just a little time and patience will pay off in the long run with a simple RTL stick and SDR#, really.
Everybody starts someplace...
Yes, a lot of folks do find it somewhat difficult to get things working but it shouldn't take more than about 5 minutes to get started. Now, where they choose to go from that point on can be much more difficult because a lot of newcomers to SDR just get frustrated with the fact that it's not a scanner like they're used to having which can be or probably was already programmed from the gitgo and it's easy to use since it's ready to go out of the box most times. Having said that, just a little time and patience will pay off in the long run with a simple RTL stick and SDR#, really.
Everybody starts someplace...
With prices like that, I kinda went overboard... I figure I need something to do this winter since we are already hitting freezing at night..
I ordered 3; RTL-SDR TCXO SMA 2x Antennas, NooElec NESDR Mini 2+, and a generic for the antenna and to try some of the beta test mods.
I love doing comparisons and testing.. helps keep the skills sharp.. at least enough to cut butter.. I will post any fun findings on the appropriate board.
I ordered 3; RTL-SDR TCXO SMA 2x Antennas, NooElec NESDR Mini 2+, and a generic for the antenna and to try some of the beta test mods.
I love doing comparisons and testing.. helps keep the skills sharp.. at least enough to cut butter.. I will post any fun findings on the appropriate board.
- Status
