SDR: Success this time

Back in May, I purchased a DVB-T mini-dongle to play around with software-defined radio (SDR). Unfortunately, I purchased the wrong type of dongle, and I couldn’t get it to work with any of the SDR software packages out there. The reason for this is that it the dongle did not use the Realtek RTL2832U.

A couple of months ago, I purchased another dongle, this time making sure to purchase the correct one. As you can see from the Amazon ad at right, this dongle cost less than 15 bucks. When I first got it, I was able to get it to run with the Windows laptop I was using down in the shack, but wasn’t able to get it to work with the Mac I use in my office. So, I put it aside, meaning to get back to it sooner or later.

Well, later came on Sunday, as about a foot of snow fell on outside. I downloaded an OSX port of the SDR program gqrx, and in short order, I was actually up and running, and listening to FM broadcast stations here in Ann Arbor. Very cool! I have since used it to listen to not only FM broadcasts, but also the local repeaters and the NOAA weather station on 162.55 MHz.

At first, I was pretty disappointed with the performance. That was the fault of the antenna, though. The antenna that came with the dongle is pretty much useless. What I did was to cut off the whip, solder on a couple of alligator clips and clip the coax to an FM broadcast dipole that came with a stereo I bought ages ago. If you don’t want to do this, you can purchase adapters cable, like the one shown at right, which have an SO-239 on one end and the MCX right angle connector, which plugs into the dongle on the other end.

That greatly improved the performance on FM broadcast as well as on 2m. I had planned on clipping to the 450-ohm ladder line J-pole that I have to see how it improves reception on 2m, but haven’t gotten around to that yet.

While gqrx is a nice program, it does have some limitations. For example, you cannot set up “memories” and switch between them. So, switching frequencies can be somewhat of a hassle. It would also be nice to have a scan feature, so that I could set it up just like I do my handheld and scan all the local repeater frequencies. The good thing is that this program is still very much under development.

The support is really good, too. There is a  gqrx Google Group where I got a very quick answer to  a newbie question.

What else can you do with this dongle? Quite a bit as it turns out. Yesterday, while composing another blog post, I learned about an RTL-SDR spectrum analyzer using a BeagleBone Black, which I already happen to have, and its 7? Touchscreen cape. Again, very cool.

Comments

  1. Had the exact same experience with GQRX on my Mac. I’d recommend buying a Male PAL to Female BNC Adapter off Amazon, or removing the PAL connector from the board was pretty easy, although I worry about twisting it off. Once I had a good antenna connection it worked much better.

    The only other issue I am running into is that you can easily overload the receiver when testing.

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