Great antenna for software defined radio is really easy to make

The University of Kent’s hackerspace, TinkerSoc, recently had a talk on software-defined radio using an incredibly inexpensive USB TV tuner. Of course this is nothing new to Hackaday readers, but they did manage to build one of the best antennas for their TV dongle. It’s a discone antenna, and is perfectly suited for tuning into a whole bunch of really cool things such as weather balloons and aircraft transponders.

The idea discone antenna looks exactly like its namesake; a metal disk attached to a metal cone. Of course with the frequencies the RTL software-defined radio deals with, it’s rarely necessary to build antennas out of sheet metal. The team at TinkerSoc built their discone out of galvanized garden wire and attached it to the input of their TV tuner.

All the dimensions for their discone antenna were gleaned from [ve3sqb]‘s antenna design programs. Since TinkerSoc designed their antenna for 110 MHz, it ended up being pretty large. For higher frequencies, though, a discone antenna become fairly small and more than portable enough for a mobile rig.

Pictures from weather satellites with a USB TV tuner

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Several times a day, a NOAA weather satellite passes over your head, beaming down pictures of weather systems and cloud formations. These transmissions aren’t encrypted, and given the requisite hardware it’s possible for you to download these images from space as [Lovro] shows us in a tutorial video.

To get these near real-time satellite pictures, [Lovro] used one of those USB TV tuners we’ve grown so fond of. A somewhat specialized antenna is required to receive the right hand polarized transmissions from NOAA weather satellites, but with a few bits of wood and wire, [Lovro] made a helical antenna to listen in on the weather satellites transmitting around 137 MHz. After gathering a whole bunch of data from the satellites with SDRsharp, [Lovro] used an image decoder to turn an audio file into a picture taken from space just hours ago.

This isn’t the first time we’ve seen images from a NOAA weather satellite downloaded with a software defined radio; last year [hpux735] did just that with a somewhat inexpensive Softrock SDR. [Lovro]‘s use of a USB TV tuner to receive the transmission from NOAA satellites is a lot easier on the pocketbook, though, with the largest expense being an investment in time to build a helical antenna.

Open source software defined radio transceiver

SDR

As the year draws to a close, we must look back and look at the advances in amateur radio this year. The RTL-SDR tuner hack, a USB TV Tuner to create a software defined radio receiver, is one of the greatest hacks of the last 12 months and a great justification for 2012 being the year of software defined radio receivers. 2013 is shaping up to have even more advances in the state of software defined radio. This time we’ll be transmitting as well, possibly with [AE9RB]‘s Peaberry SDR transceiver.

The Peaberry SDR transceiver is a kit to both transmit and receive on every HAM band between 160 meters (1.8 MHz) to 17 meters (18 MHz). It does this through a USB interface and a 48kHz, 24-bit interface that is (or will shortly be) compatible with all the major SDR interfaces.

While the Peaberry SDR requires an amateur radio license to operate, we can’t wait to see what else will be coming to the software defined radio scene in the next year.

Thanks [Zach] for sending this one in.

Building a better software defined radio (and transmitting as well)

By now most Hackaday readers should be familiar with this year’s latest advance in software defined radio. With a simple USB TV tuner dongle, it’s possible to receive FM broadcasts, GPS data from satellites, and even telemetry from aircraft flying overhead. There is one limitation to this setup, though: it’s receive only. Hacker extraordinaire [Michael Ossmann] is looking to make a better software defined radio called the HackRF.

The HackRF is an incredibly ambitious project – able to receive just about anything between 100 MHz and 6 GHz (this includes everything from the top of the FM radio band to cordless phones, cell phones, WiFi, and basically any radio technology that has been commercialized in the last 15 years), the HackRF is also able to transmit. Yes, with the HackRF it’s possible to build your own software-defined WiFi module, or just broadcast bogus GPS information.

Compared to the $20 TV tuner SDR dongles we’ve played around with, the HackRF isn’t exactly cheap. [Mossmann] figures he’ll be able to sell the device for about $300. A fair bit of change, but much, much less than professional, commercial SDR solutions.

A very cool advance in the state of SDR, but reason dictates we must suggest that everyone who wants a HackRF to start studying for their amateur radio exam now. Being a licensed radio operator won’t stop you from any sort of malicious intent, but with at least with licensing comes with the possibility of knowing what evil you’re doing.

You can check out the wiki for the HackRF over on the gits along with the current hardware design

Still more software defined radio fun on the Mac

Even though the world of software defined radio started out as a Linux-only endeavor, several recent software releases have put the ball fully into the court of OS X users. [hpux735]‘s new Cocoa Radio release provides a (nearly) fully functional software defined radio for anyone with a USB TV tuner and a mac.

Earlier this week, we saw (and tested)  [Elias]‘ port of gqrx and were reasonably impressed. [hpux735]‘s app does the same job and also provides the source so you can compile it yourself.

Previously, [hpux735] ported the osmocom driver for these RTL2832U-based USB TV tuner dongles to the Mac and wrote a small Cocoa driver. The new Cocoa Radio software uses this driver and adds all the features you’d expect from a software radio package; in the title pic for this post, you can see a top 40 radio station near my house and their insipid hatred of dynamic range.

[hpux735] posted a few videos of his development process. You can check those out after the break.

Continue reading “Still more software defined radio fun on the Mac”

Real time GPS decoding with software defined radio

In case the Realtek RTL2832u-based USB TV tuner dongle isn’t useful enough, the folks behind a project to get a software defined GPS receiver off the ground successfully plotted GPS data in real-time with this very inexpensive radio.

Previously, we’ve seen these dongles grab data from GPS satellites - useful if you’re building a GPS-based clock – but this build required hours of data collection to plot your location on a map.

The folks working on the GNSS-SDR project used an RTL2832 USB TV tuner and a Garmin active GPS antenna to track up to four GPS satellites in real-time and plot a location accurate to about 200 meters.

The Google Earth plot for this post shows the data collected by the GNSS-SDR team; the antenna was fixed at the red arrow for the entirety of the test, and the  yellow lines represent a change in the calculated location every 10 seconds. Amazing work, and only goes to show what this remarkable piece of hardware is capable of.

Hackaday Links: July 20, 2012

Hey, it’s the 43rd anniversary of men first walking on the moon. Here’s some stuff we found to celebrate that. Fun trivia: for Apollo 11, [Neil] and [Buzz] didn’t go more than 200 feet from the LEM.

This is so incredibly sad

Remember Heathkit? A lot of cool kit-based electronics came from them. They’re out of business, but you can get all the Heathkit swag you can imagine from the repo man. A ton of stuff from the old Heathkit headquarters is being auctioned off in Byron Center, Michigan this Tuesday, July 24. Notable lots include a HE-Robot and a nice pair of o’scopes. If someone wants to pick up one of the catalog lots for us, we’d be thankful.

Troll Physics: ‘What is with this guy’ edition

We’ve seen [Fredzislaw]‘s LED trickery before. The first time was a crazy 3 LED circuit, the reveal of which showed two AC power supplies in a battery connector. This time, [Fred] has two switches and an LED. Turn one switch on, the LED lights up. Turn that switch off and flip the other one, the LED still lights up. Turn both switches on, the LED goes off. Your guess is as good as ours.

Prototyping with a key fob remote

[Gary] wrote in to tell us about the dev board he’s been working on. It has either a PIC or AVR on the back side, broken out into 0.1 inch headers on the front. There’s a small solderless breadboard and an on-board RF link that uses a five-button key fob remote. Seems very useful, no matter what side of the PIC/AVR holy war you’re on.

Consumer Alerts: Software defined radio

Over on the RTLSDR subreddit, [photoscotty] bought this TV tuner dongle from Deal Extreme and received the inferior EZTV645 tuner. Unsurprisingly, Chinese manufacturers will just grab whatever is available, put it in an envelope, and ship it off on a slow boat from China. [photoscotty] is trying to return his dongle to DX, but until Sparkfun or Adafruit start selling these things (yes, there’s a market now get on it) you’ll have to be careful out there.

Wouldn’t this feel terrible against your skin all day?

[Colin] printed a watch band on his Makerbot. Apparently Shenzhen humidity didn’t play nicely with his nylon strap, so [Colin] made his own out of plastic. It’s flexible and has a neat looking clasp, as well as an awesome demo for what a 3D printer can actually do. Thingiverse files here.