How to Make a $19 Police Scanner

https://sites.google.com/site/policescannerhowto/

by rbcoffee • 13 years ago

128 53 13 years ago

sites.google.com

makomk• 13 years ago

Plus $25 for the software to actually use it.

voltagex_2• 13 years ago

I remember running into this as well - there doesn't seem to be any better software on Windows to route audio like this (AFAICR the DSD decoder software expects a "sound card" input).

oakwhiz• 13 years ago

It's a shame that audio routing is pretty much nonexistent on Windows.

pantalaimon3• 13 years ago

or you might just use Linux

blhack4• 13 years ago

This is free: http://eliasoenal.com/2012/09/30/osx-port-of-the-awesome-gqr...

nsmalch• 13 years ago

Now to commit the whole NATO Phonetic Alphabet to memory. http://en.wikipedia.org/wiki/NATO_phonetic_alphabet

mikeash2• 13 years ago

You really only need to memorize it if you're going to speak it. If you're only listening, then you merely have to know that each word represents the first letter used to spell that word.

kd0amg• 13 years ago

It depends on what you're listening to. If there's enough noise, it is helpful to know that "ahkschah" was probably transmitted as "foxtrot."

ipodize• 13 years ago

Why bother? It's intuitive enough: "Alpha" => 'A', "Bravo" => 'B', and so on...

English > NATO may not be easy without memorization, but there's no need to memorize anything if you want NATO > English.

rhizome• 13 years ago

"M as in marshmallow"

jevinskie2• 13 years ago

I want to continuously monitor for 10-codes and record incidents in a DB. Any ideas for the speech recognition portion? I figure it should be easier than full blown text-to-speech because I'm just looking for a small set of 10-codes: 10-4, 10-55, etc.

BryanB55• 13 years ago

That would be awesome. Exactly what I wanted to do but no idea how to accomplish it.

woebtz• 13 years ago

Google's WebSpeech API looks pretty good: https://www.google.com/intl/en/chrome/demos/speech.html

CMU Sphinx and Julius both also have options for continuous speech recognition, but it's quite a feat to train your own [good] language model.

swah• 13 years ago

Do things that don't scale: pay your kid to do it.

xradionut• 13 years ago

It's easy. I learned it three decades ago by this innovative method. Sing the phonetics to the rhythm of Beethoven's "Ode to Joy".

freshhawk2• 13 years ago

Doesn't take long at all and has been pretty handy to me when giving account numbers, tracking numbers, whatever to people over the phone.

They do sometimes seem surprised that you are using the "offical" words so I gather knowing this is pretty uncommon.

<nostalgia time>I learned it from The Pocket Ref book as a kid</nostalgia time>

balabaster• 13 years ago

Growing up in the outdoors and sailing, I learned to use this as second nature when relaying information - it's crazy that when you start doing this on the phone how few people understand it and you have to resort to A like Apple, F like Frank... it feels so childish after the clarity and precision of the NATO phonetic alphabet.

andyjohnson0• 13 years ago

I work on software that is used by, among others, the vehicle repair trade in the UK. The phonetic alphabet is commonly used by them to relay vehicle registration numbers over the phone. I've noticed that they rarely use it with customers though.

nknighthb• 13 years ago

In my area, the two city PDs and FDs, the sheriff's office, and the rural fire districts all use LAPD[1], not NATO. I gather LAPD is most common throughout the US.

[1] http://en.wikipedia.org/wiki/LAPD_phonetic_alphabet

blhack4• 13 years ago

I've never even heard anybody use this for anything. Huh.

For flying, and for ham radio, we use NATO.

devenson• 13 years ago

Practice the phonetic alphabet when you're on a long boring drive by spelling out the words on signs. Extra points if you spell the whole word before you pass the sign.

mcguire• 13 years ago

Extra fun tip: replace "uniform" with "unicorn".

jevinskie2• 13 years ago

Nifty! I just got two tuners so I can listen to local analog trunk systems. Any tips or recommendations for doing this on Linux?

pantalaimon3• 13 years ago

http://sdr.osmocom.org/trac/wiki/rtl-sdr has probably everything you are looking for, and more.

ajays• 13 years ago

That page you linked to is a barebones guide to RTL-SDR. Any specific tips on finding and listening to interesting frequencies (or using it as a police scanner)?

coin2• 13 years ago

How fast can the tuner change frequencies? This will impact its ability to scan.

Can the same USB receiver function simultaneously as the signal and control receiver? If not then the HW cost is $19*2.

FiloSottile• 13 years ago

Yeah, it is said at the end of the article that the system is suboptimal because the receiver will have to switch back and forth between signal and control.

coin2• 13 years ago

Wonder if it's possible to use two receivers, given that are so inexpensive ($19).

Maxious• 13 years ago

It does function simultaneously by switching away from the control channel. More advanced software like SDR-Studio or GNU Radio can extract multiple channels/signals.

superkuh• 13 years ago

According to my tests (with many dongles of E4K and R820T tuners) it takes about ~50 milliseconds for everything to happen. Use keenerd's experimental branch for fast tuning with R820T tuners. I'm not sure the main branch has fixed the driver yet. My best guess is that something in libusb is slowing down the process which in theory should only take ~8 milliseconds.

jaredstenquist• 13 years ago

Is there a Mac alternative? Otherwise i'll have to stick with my Bearcat.

ketralnis• 13 years ago

I use rtl-sdr successfully on a mac, almost everything I needed was in macports including a nice GUI

blhack4• 13 years ago

http://eliasoenal.com/2012/09/30/osx-port-of-the-awesome-gqr...

dzhiurgis2• 13 years ago

I've used a XP virtual machine, as that alternative seemed way too difficult to setup.

matthewmcg2• 13 years ago

GQRX works great, though you do have to dial the sample rate back a bit on older macs (e.g. a 2007 plastic macbook)

matthewmcg2• 13 years ago

I haven't found a native solution for trunking though.

blhack4• 13 years ago

These are really fun. I have one sitting in my Jeep with me right now.

Obviously you can do a lot more with it than just listen to cops, and even this tutorial makes it look a LOT more complicated than it is.

Plug the device in, and select a frequency. It's pretty much that easy.

I use it for listening to everything from ham radio operators to airplanes. Seriously have had every penny worth of fun playing with this.

Here is everything you need, available on amazon prime: http://www.amazon.com/Receiver-RTL2832U-Compatible-Packages-...

(Although I recommend a better antenna. Dig one out of your garage, that is what I did.)

kken• 13 years ago

Make that a <$10 SDR:

http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_sop=15&_n...

granfular• 13 years ago

Sure, a $19 police scanner.

As long as you have a $25 software package.

That runs on your $100+ Windows installation.

On your multi-hundred-dollar laptop.

Asshole.

aspensmonster• 13 years ago

And don't forget the electricity! And the rent! Clearly this headline is misleading.

aestra• 13 years ago

And internet access to read this page!!

dzhiurgis2• 13 years ago

Yes. I am reading this on a free newspaper in a tube. I expect the rest to be free.

Fundlab• 13 years ago

How to Make a $19 Police Scanner

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