Thursday, May 28, 2015

FM Radio On Your PC For 17 Bucks

Ever since discovering my new favorite toy a month or so ago, the SDR radio USB dongle for my computer, I've been finding all these fun things I can do with it.

Currently I'm living in a cabin in the woods which barely has reliable power and Internet. The big power items are my fridge and desktop computer, all being powered by a long strand of romex to the neighbor's house, and I'd rather not push it with more devices like an FM stereo receiver. I already have a sound system on my PC.

So, finding out that this SDR dongle receives stereo FM was immediately appealing to me. It took a week of playing with it, but I finally have about a half dozen radio stations getting a good signal here in a valley which is known for not getting a reliable signal for anything!

1. Get An SDR Dongle

There's a million of these dongles out there based on the Realtek RTL2832U chipset. They vary in price from about $24 all the way down to $10. I paid about $12 for mine, and I've noticed the price fluctuates a little bit in either direction with every seller almost, so look around before you buy it.

2. Get An MCX Male To Coax Male Connector

This little dongle comes with a tiny antenna which is barely good enough to show you what an awesome device you have. It might even be good enough for an urban area depending on where you are. But I'm in the middle of nowhere, so I need a real antenna. The problem is that most FM antennas are coax, and this dongle comes with an MCX connector.

In order to attach a third party antenna, you'll want to make sure you have the adapter.

Above you can see the special adapter allowing me to plug in the FM antenna

3. Get An FM Antenna

The market is flooded with thousands of different kinds of FM antennas. There's enough antennas to devote an entire blog too, not just an article. But once you have the adapter above, you can connect it to anything coax and even make an old school dipole antenna if you want.

What I ended up doing was using a fancy amplified indoor antenna like this one that my sister gave me. I bought another strand of coax cable to make it longer and ended up mounting it outside. We'll see whether it stands up to the elements. It works awesome and I haven't even connected the little signal booster it comes with.

The flat indoor antenna sitting right below the cellular signal booster antenna

4. Install The Software

Once you have the dongle plugged into a USB port  and connected to a real antenna, all that's left is to install some software. I have personally connected my SDR dongle into Android tablets and even my Raspberry Pi 2, but so far I like running it best on Windows with SDRSharp because it's so easy to use.

Below is a screen shot of what I've heard referred to as "the most complicated way possible to listen to FM radio" but I think it's cool. You also have so many more settings to fiddle with. The taller the wave form, the better the signal.

Notice that it even shows the song and station info if the station supports it

5. Fine Tune Your Antenna

Once it's all setup and you're receiving FM radio, you can move the antenna around and experiment by seeing which stations get a better signal with the antenna in different positions. I picked a spot outside right next to the cellular GSM signal booster where it gets the best reception for my favorite station and also gets good reception for the local police / fire / medical services.

Final Thoughts

Combined with a good sound system, this setup gives me great sound from my favorite station, 97.1 Charlie FM in Portland, OR. It came in at a total cost of about $17: $12 for the dongle and $5 for the adapter. If you can't find an antenna lying around or don't want to build one for free / cheap, then add the cost of an antenna and you're still nowhere near what a good FM receiver costs, and I consider this setup a good FM receiver.

Another thing to keep in mind is that most of the software programs to play FM radio could use a good chunk of your CPU's processing power if you are using an old PC or tablet. My PC is older but it has a 6 core AMD Phenom II inside of it, so there's no problem. My new quad core Raspberry Pi also plays FM radio with no problem, though I have read that older versions could have trouble with certain software.

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