Category Archives: SDR

RTL-SDR

Using A Laptop As A TV – Old School Stuff

So sometimes a really good technology just never really takes off.  A USB TV Tuner is just one such technology.

It should have taken off.  Just about everyone who has a laptop should have one of these.  I have three.

So what would you use it for?  In my case I live in a Hurricane zone and in fact got blasted by Hurricane Florence last year and had no power for several days.  (Actually I had power because I have a full house generator). Anyway, due to a concern for the amount of fuel I had on hand I shut down at times and THIS is how I got my news during those times.

Continue reading

AirSpyHF+ Spyserver on Raspberry Pi

AirSpyHF+ on Spyserver on Raspberry Pi

What is a Spyserver and why do you NEED one?  A spyserver takes an RTL-SDR software radio and allows it to be used over the network or controlled from the internet if you allow.

 

For this project I’m using the AirSpyHF+ ($199 USD).  The AirSpyHF+ is probably the BEST HF SDR radio you can get.  This project will let us operate from about 9kHz to about 31 MHz where AM radio, and Short Wave Radio reside.

Continue reading

Reading Other People’s Pager Traffic And Shit

Did you know a lot of people still used pagers? I had no clue. Did you know that all that pager traffic and all those messages are sent unencrypted and can be easily decoded? All you need for hardware is a $10 USB SDR radio stick with a cheap indoor whip antenna.

NOTE: Reading pager traffic is NOT against the law, however retransmitting it or acting on any information you learn from it is. Decode for good. Not evil.

And much like any other Linux techie project I’ve ever done following the directions somewhere else DIDN’T WORK. Oh, it mostly worked but something is always missing. This page is for the first timer trying to figure this out. And for me to recreate this once I screw it up or my computer dies.

Doing this on Windows is easiest and the directions I found here DID WORK. This will be a tutorial on Ubuntu (Or LinuxMint) Again most everything worked but the actual decoding process didn’t until I changed a thing or two. Also one major step was left out that almost caused this to epic fail for me. YMMV. Depends on the Decoder your system is using.

Continue reading

How To Keep RTL_433 Alive For Your Home Automation Using Supervisor

I run RTL_433 to push data from several sensors and a motion detector to an MQTT server for home automation.  For some reason as of late it is just not that stable. Could even be a hardware failure with the dongle….I dunno.  I generally just run the program command inside a terminal on the raspberry pi it is installed on and just walk away.  When it crashes I have to log back in the Pi and re-run the command.   Un-cool.

The command I use specifically is this:

rtl_433 -F json -M utc | mosquitto_pub -t home/rtl_433 -l

Again, that pushes data found on 433.920 MHz devices to publish a topic on my MQTT server called “home/rtl_433”.

Continue reading

Configuring Inexpensive 433 MHz Motion Sensors for use with HomeAssistant

Last week I showed you how you can capture the remote codes for cheap radio controlled electrical outlets and this week the theme is MOTION DETECTORS.  With a properly configured motion detector you can then trigger that outlet.  For example……..when you open the pantry door the light comes on………when you walk in the laundry room, the light comes on……..when someone presses the smart doorbell, the lights come on.  Pretty handy stuff.

Most home automation motion sensors send TWO signals. One when they are tripped and one when they reset.  Most of them will stay tripped for a predetermined amount of time.  Usually for 2-4 minutes or so.   Good idea to know the state of the motion detector BEFORE you buy it.

For example I have a motion detector with a 4 minute reset on it in my garage and laundry closet. That means that both of those lights that get triggered are staying on for 4 minutes whether I like it or not (unless I write some crazy code).

Continue reading

RpiTX Replay Attack on GE MySelectSmart Remote Control Outlet

Was walking around Target and saw an inexpensive remote outlet which I was pretty sure I could perform the Replay Attack on.

The Replay Attack  is when you record a signal from something and transmit it back to perform the operation.

These devices typically transmit around 433 MHz and have no encryption of any kind whatsoever.  Just a simple transmit burst for on and off functions.

Continue reading

Spyserver on Raspberry Pi

What’s a Spyserver?  And why would you want one?  Spyserver is a program for a Software Defined Radio (SDR) that allows you to access that radio from anywhere.  It also allows you to share your radio from anywhere and you can likewise share other people’s SDR radios.  Why would you want to do that?

First when the word “radio” comes to mind we tend to think of AM or FM radio only.  An SDR device is so much more than that.  It can literally listen to things from 0 kHz to 2 GHz or so.  That’s EVERYTHING that you can think of that uses a radio signal.   Short Wave, CB, Ham, pagers (yep they still use pagers), Police, Fire, EMS, the Space Shuttle flying overhead (not kidding), the tire pressure monitor sensors on your car, tracking aircraft, tracking ships, tracking weather balloons…………the list is almost endless.

Continue reading

Common Problem with OP25 in Virtualbox

I REALLY struggled hard to learn to use OP25 and once I figured It out I made a simple tutorial for myself to recreate on other computers and for others to use.  On my blog it is one of the more active pages and almost every week I get emails from people requesting help getting it working.  This is the page of instructions I made:  (there are a couple more pages that are Raspberry Pi specific but you’ll have to poke around my blog to find them).

OP25 For Dummies – Or how to build a police scanner for $30 (Part 1)

I would LOVE to help everybody but alas, I met a hot neighbor lady walking dogs a few months back and she’s cutting into my geek time!  Trust me when I say that I’m not complaining!

Most of the time I find that many users are installing Ubuntu under Virtualbox in either Windows or on a Mac and this is one of the most common errors:

Continue reading

A Tale Of Two Decoders – OP25 & DSDPlus

It was the best of decoders, it was the worst of decoders……… As you can tell I’m quite the literate bastard and highly up to speed on my Dickens.

I love digital signal decoding as it is almost something that you seemingly aren’t supposed to do, hence the attraction of it all.   There are several hunks of software that can decode digital signals and each one has it’s strength and weaknesses.  The ones I have dabbled around with are:

There are certainly others, not to mention maybe the most powerful one (but by far the one that requires the most geek foo) is GNURadio.

Continue reading