How to build powerful radio scanner

Thread Starter

CQ1830

Joined Nov 2, 2021
4
Hi ,I'm director in movies but I like electronic and telecommunication , how to I can design or build powerful radio scanner in all frequencies , my id in your website is CQ1830 , I,m noob.
 

Yaakov

Joined Jan 27, 2019
3,737
Welcome to AAC.

First the bad news: you can’t. What you are asking for is far too vague, and even if I make some educated guesses about what you might mean the scope and scale of the project is well beyond a beginner, or even a rather capable amateur.

But, there is good news: Software Defined Radio (SDR). SDR relies on computing power to demodulate and decode signals from relatively simple, wideband radio hardware. You can get started cheap, and do an amazing range of things with it.

My suggestion is to look first as RTL-SDR (quick start guide here) which is an open source focused SDR system based on very cheap USB dongles originally intended for digital TV reception. WIth a dongle, a computer, and one of several open Source programs you can get a start in SDR.

Once you have some idea about it, you can begin to decide what capabilities your scanner should have, and produce a real set of specifications that can be turned into a workable design with SDR at its core. Using traditional radio technology for such a project would be a non-starter for an individual neophyte, but with SDR you can have success at each step and revisions are just different code instead of wasted PCBs.

Good luck with your learning.
 

SamR

Joined Mar 19, 2019
3,607
Well, the first thing you will need is a high gain all band antenna. All the radio does is process the signal it receives from the antenna. If you amplify the signal from a poor antenna all you get is amplified noise. The newer and better all band radios have significantly advanced Digital Signal Processing that is proprietary and difficult to homebrew. The less expensive route as Yaakov said is the SDR-RTL dongle and software that uses your computer to do the DSP. But once again it depends on the antenna. The old GIGO (garbage in garbage out) applies here.
 

ronsimpson

Joined Oct 7, 2019
1,631
"Software Defined Radio"
SDR YouTube videos about SDR.
Start off with this link and watch several videos. This radio type is very flexible and has a scan function. The hardware is low cost and done for you. You will know if this is right for you in a couple of videos.
 

BobTPH

Joined Jun 5, 2013
4,032
It just it occurred to me that “powerful” is an odd way to describe a receiver. A transmitter can be powerful, the analogous attributes for a receiver would be “sensitive and selective.”

Bob
 

Thread Starter

CQ1830

Joined Nov 2, 2021
4
Thanks for all the friends who answered me, SDR is very interesting, but I mean what steps should go so that I can design a circuit for radio scanners and then make it.
 

Yaakov

Joined Jan 27, 2019
3,737

Yaakov

Joined Jan 27, 2019
3,737
Thanks for all the friends who answered me, SDR is very interesting, but I mean what steps should go so that I can design a circuit for radio scanners and then make it.
Your project is impractical. It would take you years to get to the knowledge level necessary. Sorry I can't help more.
 

Irving

Joined Jan 30, 2016
2,308
but I mean what steps should go so that I can design a circuit for radio scanners and then make it.
Given your obvious complete lack of knowledge on the subject, can I suggest you take a course in basic radio technology so you can at least explain and specify what you want/need. Then a course in advanced radio design, followed by 5y learning and experimenting until you know how its done.... because that's about where I was 35y ago and that's about 1/2 competent.

That's not intended as an facetious answer, merely fact. When you can talk authoritatively about subjects such as sensitivty, bandwidth, signal-to-noise ratio, noise floor, modulation modes and depth, etc., etc., then you might be on the right track...
 
Hi ,I'm director in movies but I like electronic and telecommunication , how to I can design or build powerful radio scanner in all frequencies , my id in your website is CQ1830 , I,m noob.
Hello CQ1830
First, a little encouragement. If a rock and roll star can become a consultant on missile defense to the pentagon, perhaps a director in movies can figure out how to build a powerful scanner. Check theses two videos out:

1st Video

2nd Video

While watching keep in mind that the artist that is playing the gutter (white hair, handle bar mustache) may not be familiar to you, but he is well known in the 60's and 70's generation where he composed and played with some very good bands. While watching the second video, pay attention to the discussion on "non-linear thinking" and frequency effects. It won't solve your problem but should give you some encouragement.

Now, as for your question; many have given you great answers. I thought I'd chime in to offer my 10 cents. As with any project, you need to define your requirements. "A powerful radio scanner" is a good start, but what are the requirements? For example:

1. Shall receive signals from frequencies x to y
2. Shall demodulate the following modulated signal (e.g. AM, FM, SSB, QPSK, etc.
3. Shall to have a sensitivity of z.
4. Shall use analog or digital (DSP) Technology.
etc.

This is a simple, and incomplete requirements list, but you get the idea. If you decide to use analog circuit design, you have quite a task ahead of you. On the other hand, if you decide to use digital signal processing (DSP) the good news is that there are exciting tools to use. The bad news is that there is a steep learning curve.In either case (analog or digital) there are still requirements to understand analog circuits with digital (e.g. the frontend of the receiver needs to filter, amplify, and digitize (sample) the signals you are targeting.

Some example of tools are: GNU radio (free). This is a wonderful tool that you can build all kinds of digital signal processing circuits and, with a cheap "dongle" like the RTL SDR, or more expensive HACKRF ONE, you can implement many kinds of radio receivers. You need a fair power full (modern) computer. GNU radio is typical a Linux OS application, but Windows is also supported. Although I am a MacOS fan, I have never attempted installing GNU on MacOS. There is even an effort to run GNU radio on some new embedded systems. In particular, the Xilinx Ultra96 FPGA. This is very exciting in my opinion, but the effort is not mature yet.

If you want to think really big, using and FGPA you can implement a direct conversion receiver but not in all bands.

This is just a sampling of what is possible. I don't mean to overwhelm (nor talk down to you). I want you to be inspired and learn more about the above if you are so inspired. Remember what I said about non-liner thinking and the second video. Google 'Jeff "Skunk" Baxter and pay attention to his discussion on non-linear thinking. Use Google to learn more about the technology are course on-lin and, of course, Google.

I hope this give you some inspiration and encouragement.

Dave
 
Last edited:

Thread Starter

CQ1830

Joined Nov 2, 2021
4
Hello CQ1830
First, a little encouragement. If a rock and roll star can become a consultant on missile defense to the pentagon, perhaps a director in movies can figure out how to build a powerful scanner. Check theses two videos out:

1st Video

2nd Video

While watching keep in mind that the artist that is playing the gutter (white hair, handle bar mustache) may not be familiar to you, but he is well known in the 60's and 70's generation where he composed and played with some very good bands. While watching the second video, pay attention to the discussion on "non-linear thinking" and frequency effects. It won't solve your problem but should give you some encouragement.

Now, as for your question; many have given you great answers. I thought I'd chime in to offer my 10 cents. As with any project, you need to define your requirements. "A powerful radio scanner" is a good start, but what are the requirements? For example:

1. Shall receive signals from frequencies x to y
2. Shall demodulate the following modulated signal (e.g. AM, FM, SSB, QPSK, etc.
3. Shall to have a sensitivity of z.
4. Shall use analog or digital (DSP) Technology.
etc.

This is a simple, and incomplete requirements list, but you get the idea. If you decide to use analog circuit design, you have quite a task ahead of you. On the other hand, if you decide to use digital signal processing (DSP) the good news is that there are exciting tools to use. The bad news is that there is a steep learning curve.In either case (analog or digital) there are still requirements to understand analog circuits with digital (e.g. the frontend of the receiver needs to filter, amplify, and digitize (sample) the signals you are targeting.

Some example of tools are: GNU radio (free). This is a wonderful tool that you can build all kinds of digital signal processing circuits and, with a cheap "dongle" like the RTL SDR, or more expensive HACKRF ONE, you can implement many kinds of radio receivers. You need a fair power full (modern) computer. GNU radio is typical a Linux OS application, but Windows is also supported. Although I am a MacOS fan, I have never attempted installing GNU on MacOS. There is even an effort to run GNU radio on some new embedded systems. In particular, the Xilinx Ultra96 FPGA. This is very exciting in my opinion, but the effort is not mature yet.

If you want to think really big, using and FGPA you can implement a direct conversion receiver but not in all bands.

This is just a sampling of what is possible. I don't mean to overwhelm (nor talk down to you). I want you to be inspired and learn more about the above if you are so inspired. Remember what I said about non-liner thinking and the second video. Google 'Jeff "Skunk" Baxter and pay attention to his discussion on non-linear thinking. Use Google to learn more about the technology are course on-lin and, of course, Google.

I hope this give you some inspiration and encouragement.

Dave
Hell and thank you for your support ❤❤❤❤❤
 
I don't know anybody who ever went straight into electronics and designed anything more complicated than a flashlight, and many of us had trouble with that. Most of us had our first radio experience with kits or building simple circuits out of books and magazines. To get you closer to your goal in a short amount of time, I suggest you take Yaakov's advice by starting with an inexpensive Software Defined Radio. These things are magic compared to the radios of the days I started learning about radio.

SDR dongles are inexpensive and come well supported with software to operate them and they often give very wide spectrum coverage.

Advice from SamR in post #3 about antennas is something you will want to heed as soon as you know what frequencies interest you. Good antennas cost something (money, time, space, etc.) and usually are only good for specific frequency ranges, but as he points out, with a poor antenna or the little untuned whip antennas that come with some of the SRD dongles you won't be able to hear things very far away.

Here is a simple SDR receiver, probably one of the simplest ones around.
https://tapr.org/pdf/DCC2010-simpleSDR-KF6SJ.pdf (PDF file)

The trick is to get started and don't stop until you get somewhere you like. It is a long way from being a noobie to being able to design, build, and debug a receiver, but if you don't take that first step, you will never get there.
 
SDR is probably your best bet. The frequency coverage is really great and a good antenna will help but even with a basic SDR you'll get going. The goto SDR kit at presently is the HackerOne kit which will set you back $400 but is probably one of the most popular units but look around and watch some youtube videos and you'll get some more insight. Good luck
 
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