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Radio

Awesome Radio Awesome

A curated list of awesome radio resources. Inspired by awesome-*.

I recently pulled out my CB radio and installed it in my truck. This inspired me to create an open source repository of all the radio related resources I found helpful and my notes on the subject.

This project is aimed at hackers who enjoy all aspects of radio communication. While a lot of this technology isn't usable by citizens and is heavily regulated by the FCC, just knowing anything about it is special. I've been interested in learning the ins and outs of radio, as well as hearing stories, new and old.

General

CB

Citizens band radio, or CB, is a two way radio spectrum dedicated to open use by anyone for almost any purpose. In the US and many other countries, it does not require a license to operate. CB consists of 40 channels between 26.965 MHz and 27.405 MHz with channel 09 being dedicated to emergencies.

CB is more popular among truckers and radio enthusiasts, but its usefulness does not stop there. It's great for long distance travel on popular trucking routes. You can tune to channel 19 (an unofficial trucker's channel) and get real time traffic updates, alternate routes and accident warnings.

Given a good antenna that's properly tuned, a typical range to expect out of your CB is about 2 - 5 miles (3.2 - 8 kilometers).

General Use

I've found a lot of my information on Jeep and trucker forums. From my own experience, it seems about half the CB transmission I hear include a handle of some kind. I also hear a lot of swearing, so I wouldn't sweat accidentally letting a "fuck" or a "shit" go.

CB is public. Very public. That seems like a "no shit" kind of thing, but with the current generation pretty much only using cell phones, it's easy to forget that using something as "primitive" as a CB radio is essentially broadcast to the world.

Truckers tend to use channel 19. This is a good channel to monitor for traffic conditions.

Channel 9 is for emergencies only. No general chatter on this channel. If you are broke down, or your car catches fire, besides calling 911, this is a good channel to transmit on for help.

Around Portland, I hear a lot of chatter on channels 6, 17 and 28. These are good channels for entertaining conversation.

SWR

SWR, or Standing Wave Ratio is a measurement of efficiency when connecting your antenna to your radio.

Optimum ratio is 1:1, although you'll probably end up with 1.3:1 or so. Anything higher than 2:1 should be considered a no-no since it can damage your radio and give poor transmission. Read up on how to tune SWR.

Installing a mobile CB

Installing your CB right is key to A) not damaging your radio hardware and B) getting good range and quality on both the receiving and transmitting ends.

Following the advice in the following articles will ensure you have a quality setup.

SDR (Software Defined Radio)

Software Defined Radio is a way to define components that are typically hardware, such as filters and amplifiers, as software. It has been around for a while, but with the cost of digital electronics needed to run SDR becoming increasingly cheaper, we are seeing a rise in hacker folk playing and building with SDR.

I would like contributors for this section.

Hardware

  • Recommended starter hardware On the low end, RTL-SDR is a super-cheap usb dongle, around which a thriving community has been founded.
  • On the other side of the cost spectrum, pervices makes some really high-throughput, PCIe devices for when you need to log all the traffic ever. The software and community support for this is less good, though (for which you can blame @outofculture).
  • You can also browse through the big list of all compatible hardware.
  • Antennas are their own body of options and tradeoffs, about which I know nothing.

Software

Depending on the hardware you're using, it may ship with some demo software to play around with. This is great for just getting a chance to see some waves and start to get an idea of what's possible. Otherwise, GNU Radio is going to where you'll spend your time. It's mainly just a library, but it also has a supporting gui for combining processing blocks that then outputs python. Once you're more comfortable, you can also just use GNURadio to do any device tuning, setup and i/o, and then use numpy for the signal manipulation math.

Just visualizing and manually inspecting a signal is a valuable part of learning how to work with them. Baudline is a janky old thing, but it's the best there is. Be forewarned that learning the UI won't come easily to anyone.

Amateur Radio (a.k.a Ham Radio)

The hobby of Amateur Radio has a long and proud tradition. The very first radio amateurs were true pioneers of radio technology. Amateurs 'invented' and refined much of the early radio technology and were the first to transmit music, radio plays, and information to the handful of people who had the new fangled radio receivers.

After World War II the hobby of amateur radio flourished. Radio clubs sprang up in schools all over the world and kids went home each night to build some new contraption, or have a chat with someone over the wireless. These young people became the mainstay of the technical professions and developed much of the modern technology we use today. (WIA)

What is Ham Radio?

I would like contributors for this section.

Amateur Radio License

Public Health and Safety

Police and fire in the United States typically communicate over trunked radio. This makes it hard to scan using normal reciever without trunk tracking abilities. See more in the trunking section.

Trunking

While not strictly specific to public health and safety, it is usually the first thing that comes to mind when talking about trunked radio.

Trunked radio is a form of digital-two-way communication where multiple organizations can share a small spectrum of real frequencies without hearing another organizations conversations. A user can choose a logical channel or group and the base station will find an empty frequency to transmit on.