Low-cost scanner

[Singlestack]

I have been reading about software-defined radio (SDR) over the past several months, and have been especially impressed with the capabilities for the price. I asked for some basic components for my birthday a week ago, and everything is running pretty well right now.

The software runs on a computer with a USB port. I'm using a low-end Windows 8 touchscreen notebook I got for Christmas, and it runs fine.

You will need a USB TV tuner dongle (I got the Nano 820T dongle from the Nooelec website) - I think I paid about $20 for it. It comes with a tiny antenna that is ok for checking it out, but you will want a better antenna.

For the better antenna, I got an Antennacraft ST2 wideband scanner antenna - cheapest place to buy is the Radio Shack website for about $45. It comes with 50' of RG-6 coax and a Type N to BNC adapter. For the price, the antenna is a steal. It can tune from about 30 MHz to about 1.7 GHz.

The Nano dongle has a miniature MCX RF connector on it. On the Nooelec website, you can buy a small cable that is MCX at one end and BNC at the other. So for less than $75 you can have the whole thing.

The 2 main software packages (both are free) that you will need to download install are SDR# ("SDR Sharp") and HDSDR. You can google them and get all the info to help with installation. There are also quite a few Youtube videos to help get you familiarized. I am using HDSDR, but I think either should work fine.

There are 2 things this setup doesn't address: HF radio and digital (like Mototurbo or APCO 25). For HF, you will need an RF upconverter, like the Ham it up Upconverter from Nooelec. I have it, but haven't tried it yet. You will also need a suitable antenna to tune the HF frequencies you are interested in. The ST2 covers 6M (VHF) and the 11M stealth band, but 10M (28MHz - 29.7 MHz) may be dicey.

For digital, you will need to download and install a suitable program like Unitrunker. Some cities (Longmont, e.g.) and public services use trunked digital, and that is what Unitrunker can help with. Note that no scanner, even the high end models, will be able to decode encoded digital comms. Fortunately, very, very few non-mil entities have that capability. I hope to get Unitrunker installed etc in the next week or 2.

Lastly, you will need to know what you are listening to. Go to the Radioreference website, enter your zip code, and you will get a very useful list of county, city, and emergency service (police, fire, ems, roads/plows,...) frequencies and related information. The list is organized by function, and not frequency. I think you will also need a frequency-organized list. I am creating an excel spreadsheet that does just that for my local stuff.

When you look at the display, you will see a waterfall display covering a range of frequencies. You can position the cursor over a specific frequency and zoom in, adjust bandwidth, squelch, and use various digital filters to help with intelligibility. Note that this is a receive-only setup. and therefore does not require any license to use.

With the ST2 antenna in a good location (upstairs in my house, in my case), it is amazing how much you can hear. I was listening to Centennial Police and fire dispatch for awhile, from Boulder County. Completely clear and noise-free.

I am in the process of putting together a smallish solar system to keep the notebook and scanner running in case of power down. This will hopefully work well and give me some improved situational awareness in case of emergency. I highly recommend it, especially for the price.

[Irving]

Can this be run without the Internet?

[Great-Kazoo]

I have no clue what he said, but it sounds interesting. I have an old police scanner, pretty useless since they went to cell phones & laptops. It does function in bumfuk kansas.

[Cman]

I have to agree with GK, sound cool but I have no idea what was said!

[gnihcraes]

Glad to see some cheap fun in the scanning world. I wish you could do the edacs apco25 stuff. (non encrypted channels)

I prefer mobile scanning though, you can have more fun listening to target stores complain and make fun of customers, then move on to another location and listen to FRS in the hood somewhere.

I currently listen to the Tower crane and construction site near work from my desk. Interesting stuff.

[Singlestack]

Guys,

Sorry about the confusion. I'll try to be a little more descriptive of what this is about.

Irving - only requires the internet to download whatever software package and add-ons are needed. Operating doesn't use the internet at all - you just need to be able to power whatever computer is running this.


OK, now I'll try to discuss the big picture and what this is good for. I apologize for being so long-winded!

Radio Frequencies include tons of communication stuff. Some are ham radio bands, some are emergency services bands (police, fire, ambulance, ems,...), some are public service frequencies (XCEL energy and Kelly's crane operator, for example), some are aircraft, some are marine, some are local communications like CB, FRS/GMRS, MURS, etc. Some are analog, some are unencoded digital, some are encoded digital, some are broadcast radio stations (both AM and FM), some are voice, some are CW (morse code), some are digital (like packet, D-Star, MOTOTRBO, and P-25).

Covering everything used to take several pieces of gear, including ham radios, wideband communication receivers, and shortwave receivers - and knowledge of how to operate all of them. A BIG investment of $$ and time. Several years ago, radios and receivers started to include full-blown computers as their core, instead of RF discriminators, analog filters, analog tuners, and all of the other hardware needed to make a complete radio/receiver. That old hardware tended to be very expensive, and often require precision components. As you know, computers have gotten more and more powerful over the past 34 years since the IBM PC. Prices have come down and you get more and more technology for less and less money. I used to design PCs back in the 386/486 era, and all smartphones today are much more powerful computers than the most powerful 486 computer in 1986-87.

What companies discovered over time is that the complex RF (radio frequency) functions performed by an old-school radio or receiver can also be performed by a computer. You must first convert RF signals from an antenna to baseband analog, then from baseband analog to digital (That's what happens in the USB dongle I mentioned in the OP). Once in digital, software that runs on the computer can do very complex things on the digital data stream like discriminating, filtering, and so on. The software contains very complex algorithms that perform digital signal processing and other functions, while running a graphical user interface that allows a user to understand what the antenna is receiving.

The ham radio world is full of hobbyists that love to experiment and try new things - many are not in it to make $$ and this is what they do for fun. That is the genesis of software-defined radio (SDR). Now, there are many full-fledged companies that sell very feature-rich SDRs - usually at a discount to what a conventional radio with similar capabilities would cost. (Note: "conventional" radios these days contain most of the computer hardware within, which is not exactly what is in a PC, but similar). SDRs use off-the shelf computers like desktop computers, notebook computers, tablets, and in some cases smartphones - for the computer functions. The computers run todays PC Operating systems - XP, Windows 7/8, Apple, Linux, or even Android.

The term "SDR" these days usually means a ham radio implemented as a conventional antenna (for whatever bands you want to use), an RF converter box (like the USB dongle, but more capable), and software applications you buy from the SDR manufacturer. The term "SDR" also seems to be used for the USB scanner dongles and associated software. BTW, the USB scanner is really nothing more than a TV tuner! The idea is you could watch broadcast TV on a computer somewhere, even without an internet connection. Several years ago, TV signals in the US were broadcast over the RF frequencies - but then the FCC eliminated broadcast TV. Now it requires a cable or a satellite feed in the US. However, broadcast TV is still happening in much of Europe, so these TV tuner dongles sell like hotcakes over there.

One very cool part of SDR (the scanner paradigm) is the software is free and it gets better and more feature-rich all the time (and you don't pay for the upgrades either)! Everyone owns a computer, so the most expensive hardware is usually already paid for. All that is needed is a way to get the signals (antenna and dongle) into the computer. Yes, you can go and buy a high end Uniden digital trunking scanner for $600 - but even that doesn't do everything a scanner SDR does. The biggest thing the scanner SDR does NOT do is decode encoded transmissions, but no gear available to the general public does that anyway.

I wouldn't call my setup "portable" or even "mobile" - although with a different antenna it could be. I plan to use it for (mostly) local situational awareness at my house in the event of a natural disaster or a grid down/social unrest situation.

BTW, a book a recommend very much is "Grid down communications" Volume 1 by Sparks: http://www.lulu.com/us/en/shop/spark...-21547051.html
For $11 includes lots of useful info on lots of comm options. It came out on March 24th of this year, so it is very current.

I hope this helps, guys. Although SDR is getting more and more popular, there are still many who have never heard of it. There are lots of Youtube videos and internet sites that talk a lot about SDR and show it in use. My take is that for $75 this is a no-brainer that with some practice can provide a huge upgrade in awareness. It by no means replaces ham radio and I think ham radio gear is very complementary to the scanner SDR capabilities.

[ChunkyMonkey]

Tag.. maybe one day my slow mind will understand.

[cofi]

So trunked systems are not encrypted????

[asmo]

All of CO is trunked. There are a few places moving out encryption in the near future. The two are not mutually exclusive.

[Joe Manco]

Alpha/numerical display,Trunking, battery operated mobile scanners are not that expensive and everything can be downloaded to them pretty easy these days. Ratshack or Uniden are just a couple of many popular brands. I sometimes go to buckley airforce base and listen to the tower(not trunked) to get advanced notice of incoming aircraft to photograph.