DIY Scanner

DIY Scanner Help

Hello,

I'm not too sure if this is the correct category for this thread, but I'll try anyways.

I came across this article: How to Make a $19 Police Radio Scanner

It looked pretty viable. The only problem, is I can't really obtain that USB Antenna as shown in the article.
Would there be any alternatives?

Thank you.

for no money except membership to rr just listen here on RR

ant888 said:

It looked pretty viable. The only problem, is I can't really obtain that USB Antenna as shown in the article.
Would there be any alternatives?

Click to expand...

There are lots of different USB receivers based on the RTL2832U chip with either the R820T or R820T2 tuner inside. NooElec has a variety of them, in a wide range of different sizes and capabilities. I've personally picked up two of their NESDR Nano2+ USB receivers ($23 each on Amazon, link below), along with MCX to BNC antenna adapter cables so I can use my own antennas with them. I've used them with SDR#, CubicSDR, and UniTrunker. I've not yet delved into DSD or any digital voice decoding yet.

https://www.amazon.com/NooElec-NESDR-Nano-Ultra-Low-Compatible/dp/B01B4L48QU/

ant888 said:

Hello,

I'm not too sure if this is the correct category for this thread, but I'll try anyways.

I came across this article: How to Make a $19 Police Radio Scanner

It looked pretty viable. The only problem, is I can't really obtain that USB Antenna as shown in the article.
Would there be any alternatives?

Thank you.

Click to expand...

I'm not sure what you mean by "USB Antenna", the current RTL dongles have an SMA F Connector for the antenna connection, just like you'd see on a hardware radio or scanner. When when you buy the dongle, most people also buy a SMA to BNC jumper cable, allowing you to use any antenna you wish. The dongles are sold with and without antennas. I always buy them without the stock antennas (which are crap). If you don't currently have antennas, get a proper antenna from Scanner Master or Ham Radio Outlet. If you head to the Antenna Section of RR forums, you can even find instructions for building something yourself.

I think the OP is under the impression that the entire device pictured in that article is a USB antenna and that's where the mistake is coming from. I'll add this edited version for clarification that might help:



The RTL-based stick - so named because it uses the popular Realtek RTL2838U USB controller chip (that's what RTL comes from, don't ask why since it should be RLT I suppose) - uses a tuner chip made by a company called Rafael Microelectronics and the original model is known as the R820T while the newer improved version is known as the R820T2. The "cheap USB TV tuner" pictured above is one of the very popular NooElec models using the original R820T chip - if you're planning to make a purchase you'll want to get one of the newer sticks based on the R820T2 chip (better sensitivity, a little less noise, just better overall) that will probably also come with some kind of aluminum or metal housing (shields if from RF interference) as well as providing a better antenna connector (either the F style coax connector like you'd use with cable TV hardware) or the more appropriate SMA connectors that are becoming the standard nowadays replacing the old school BNC connector.

Lot of information to work with, yes, and some of it doesn't really matter suffice to say it's indeed possible - if you already have a computer running Windows, or OSX/macOS, or even Linux in some instances - to pay anywhere from $10 to $30 given taxes and shipping in most instances and end up buying one of these RTL-based sticks and actually monitor your local police department as long as they're not using encryption on their communications.

If it's analog it's very easy to monitor with such a setup; if it's using some digital format like APCO P25 Phase I or Phase II digital modes, or DMR/MOTOTRBO, or NXDN (which you may or may not know about or even understand just yet) or something else will require more effort on your part and more software on the computer but the simple fact is:

Yes, you can monitor your local police/fire/EMS/etc or anything else that uses analog and digital modes of communication in today's world as long as it's not encrypted - the reason I repeat the encryption aspect is because none of the modern SDR software you might use (not only for tuning but also decoding the digital modes) will decrypt signals.

A lot of learning to do, ant888, and yes you'll have to get one of those RTL-based sticks (or some other SDR hardware) but it's pretty cool to be able to listen in using such tools and not just relying on a classic handheld or desktop/mobile "police scanner."

Welcome to RadioReference also.

Just as an addition: I wouldn't recommend the particular RTL-based device that mikev provided a link for in his post above: it's not a very good device overall (in comparison to something that costs about the same money, is shielded, and uses the better SMA antenna connector) such as this:

https://www.amazon.com/dp/B011HVUEME

A few bucks more, does more (can even pick up "shortwave" now under 25 MHz and lower), and is just better overall. No, I don't get any kind of kickbacks from mentioning it, but it's better as a device to start with for a few bucks more. The one that mikev linked to uses the older MCX style antenna connector and it's just nearly as useful as SMA is nowadays, you'd end up having to buy extra adapters of various kinds to make that stick work with better antennas that will probably be SMA by default anyway so, the better RTL stick with the SMA connector is a no-brainer.

br0adband said:

I think the OP is under the impression that the entire device pictured in that article is a USB antenna and that's where the mistake is coming from. I'll add this edited version for clarification that might help:

The RTL-based stick - so named because it uses the popular Realtek RTL2838U USB controller chip (that's what RTL comes from, don't ask why since it should be RLT I suppose) - uses a tuner chip made by a company called Rafael Microelectronics and the original model is known as the R820T while the newer improved version is known as the R820T2. The "cheap USB TV tuner" pictured above is one of the very popular NooElec models using the original R820T chip - if you're planning to make a purchase you'll want to get one of the newer sticks based on the R820T2 chip (better sensitivity, a little less noise, just better overall) that will probably also come with some kind of aluminum or metal housing (shields if from RF interference) as well as providing a better antenna connector (either the F style coax connector like you'd use with cable TV hardware) or the more appropriate SMA connectors that are becoming the standard nowadays replacing the old school BNC connector.

Lot of information to work with, yes, and some of it doesn't really matter suffice to say it's indeed possible - if you already have a computer running Windows, or OSX/macOS, or even Linux in some instances - to pay anywhere from $10 to $30 given taxes and shipping in most instances and end up buying one of these RTL-based sticks and actually monitor your local police department as long as they're not using encryption on their communications.

If it's analog it's very easy to monitor with such a setup; if it's using some digital format like APCO P25 Phase I or Phase II digital modes, or DMR/MOTOTRBO, or NXDN (which you may or may not know about or even understand just yet) or something else will require more effort on your part and more software on the computer but the simple fact is:

Yes, you can monitor your local police/fire/EMS/etc or anything else that uses analog and digital modes of communication in today's world as long as it's not encrypted - the reason I repeat the encryption aspect is because none of the modern SDR software you might use (not only for tuning but also decoding the digital modes) will decrypt signals.

A lot of learning to do, ant888, and yes you'll have to get one of those RTL-based sticks (or some other SDR hardware) but it's pretty cool to be able to listen in using such tools and not just relying on a classic handheld or desktop/mobile "police scanner."

Welcome to RadioReference also.

Just as an addition: I wouldn't recommend the particular RTL-based device that mikev provided a link for in his post above: it's not a very good device overall (in comparison to something that costs about the same money, is shielded, and uses the better SMA antenna connector) such as this:

https://www.amazon.com/dp/B011HVUEME

A few bucks more, does more (can even pick up "shortwave" now under 25 MHz and lower), and is just better overall. No, I don't get any kind of kickbacks from mentioning it, but it's better as a device to start with for a few bucks more. The one that mikev linked to uses the older MCX style antenna connector and it's just nearly as useful as SMA is nowadays, you'd end up having to buy extra adapters of various kinds to make that stick work with better antennas that will probably be SMA by default anyway so, the better RTL stick with the SMA connector is a no-brainer.

Click to expand...

Thanks for explaining; so, there's no alternatives to the USB receiver? (Sorry, I'm new to this).

To be effective, you will need to spend more than $19. For any modern trunking system, you need one dongle to monitor the control channel and another device to handle the voice traffic. Then, You will need to buy an effective antenna. Then you will need to buy the coaxial cable to connect This. Also, you will need the appropriate connectors to connect the cable to the devices. Finally, you will need an appropriate antenna mount to attach your antenna to it's mounting location. You can get there for under $100.

AntiSquid disclaimer: All information provided is personal opinion only and may or may not resemble actual fact.

You can use any SDR "dongle" to do this, including the RTL-SDR, SDRPlay, HackRF One, ... (not all of them are thumb-drive form factor).

However, for analog / non-trunked stuff I would highly recommend a BC125AT.

In general, the SDR route has some very interesting and geeky capabilities with a lot of potential. However, they are not as sensitive or easy to use as a commercial scanner. (And, of course, you need a PC in addition to that ~$20 - $300 SDR device.)

With just one single SDR device, even something as low end as a $10 RTL-based "cheap USB TV tuner" that comes with an antenna (which can be modified to perform much better than the default configuration) - and as long as you already have a desktop or laptop computer that's capable of running Linux, preferably Ubuntu (at least 14.04 but more likely 16:04 which is the latest release), you can monitor P25 Phase I and Phase II systems without any issues - both the control and the voice channels from just the one tuner/SDR device.

It's not easy to do this, it's not just plug it in and click an icon and you're going in 5 minutes or less, not even, but it is possible. With a second RTL-based device (for cost considerations since they are so low in price) then you can do even more with other digital modes like DMR/MOTOTRBO/NXDN and the other popular digital modes as well.

If you want a working "police scanner" that's as simple as pushing a few buttons - no computer required - that's where actual physical scanners fit in. SDR is just a way to open up a new methodology using computers and software coupled with devices/tuners that are controlled by the software running on those computers and not just the firmware inside the tuning device itself. This opens up an entirely new world of potential that physical scanners simply can't do, even if they offer a level of computer controlled operation (which most all have done for the past decade or longer).

Basically, almost anything is possible right now using one of these simple RTL-based sticks, a computer running the necessary software, and time and patience to learn how to get it all working to produce output you want to monitor from the sources you want to listen in on. The only absolute thing that won't work at this point (and probably never will) is direct reception and decryption of systems that are encrypted, that's about it.

Anything else that's in use is fair game (depending on your local laws, etc).

ant88: The only alternative to monitoring without paying a cent (well, at least not for additional hardware to do it) would be streaming from Broadcastify.com's "police scanner" streams to your computer/smartphone/tablet. You'll still be paying for the Internet service probably, the computer/smartphone/tablet you're using to do it, electricity to keep it running, etc.

But the simple answer is if you want to do what your original post was hinting at, you'll have to spend anywhere from $10 to $30 to get one of those "cheap USB TV tuners" to work with. Your computer alone doesn't have a radio (and I don't mean FM like the stations in your area that play music and news) inside it that can be made to work as a wideband communications receiver - that's what spending $10-$30 gets you.

There's a lot of content out there streaming online and all you have to do is visit their sites and start listening with a computer/smartphone/tablet, basically at no additional cost. But if you really want to get serious about doing more with one of those RTL-based sticks, you're going to have to spend just a little money (like pass on eating at McDonald's or Burger King a few times a month, bam, now you've got the money to buy one of them like the one I linked to above from the RTL-SDR blog).

It ain't a lot of money to spend - obviously you have a computer or a smartphone or a tablet device already because you're posting questions here at this forum and you've got to have some kind of computer device with a web browser to do that.

A few bucks, a whole world of monitoring potential. I think it's worth it.

UPMan said:

You can use any SDR "dongle" to do this, including the RTL-SDR, SDRPlay, HackRF One, ... (not all of them are thumb-drive form factor).

However, for analog / non-trunked stuff I would highly recommend a BC125AT.

In general, the SDR route has some very interesting and geeky capabilities with a lot of potential. However, they are not as sensitive or easy to use as a commercial scanner. (And, of course, you need a PC in addition to that ~$20 - $300 SDR device.)

Click to expand...

Geeky... yeppers.... That's why i like 'em

I've got two of the RTL-SDR dongles that Br0adband linked to above, and they do a great job. The two antennas that come with them are much better than the one that came with the NooElec SDR dongles that I have.

The SDR setup I used for scanning an EDACS ProVoice trunked system is two of the RTL-SDR dongles, the two short antennas that come with them, Unitrunker (which is free) and DSD+ (I use the paid fastlane version, but the free one works fine). You can get this for about $50.00 and with a bit of setting it up on your computer, you will be scanning your local trunked system fine.

I currently use a Uniden BCD536HP for receiving this sytem, and while it is more sensitive and does a better overall job receiving this system, the RTL-SDR setup was perfectly acceptable.