At the beginning of March we posted about Tom Zicarelli who had created a Max/MSP wrapper for the RTL-SDR. Back then he said he was also working on a wrapper for PureData (PD). Now Tom has written the wrapper and uploaded a video showing a demonstration of the RTL-SDR working in PD. He has also uploaded a new Max/MSP wrapper video. Tom plans to make the wrapper available in the next few months.
Max/MSP and Pure Data are graphical programming tools for creating music, sound, video and interactive graphics applications.
Tyler Watt has posted over on his blog a new post showing some tips on the use of SDR#. He makes use of animated gifs to clearly show the action in SDR# that he is performing. If you’ve been wanting to learn more about how to use SDR#, or what the various options do, check out his guide.
To do this he used the RTL-SDR Scanner software which allows you to create a composite spectrum over a frequency range wider than the maximum 3.2 MHz of bandwidth the RTL-SDR provides. The wideband noise generator was cleverly constructed out of a diode operating in it’s reverse breakdown mode.
Apart from the obvious excessive spurs, this method worked quite well and the shape of the filter is clearly visible.
In Boulder, Colorado (and possibly other US cities) there is a radio based weather monitoring system known as ‘Urban Drainage and Flood Control’. This is a system that monitors rainfall and other weather information and transmits data using the ALERT protocol.
Using his RTL-SDR and GQRX, he made a recording of some of the weather station packets on that frequency. Next he used a command line utility called minimodem to convert the recorded packets into binary data. After looking up the protocol online, he was then able to understand the binary string and extract the station ID information from it. Cparker then went on to write code that would plot the received stations on a map by cross referencing the station ID with a website containing location information about these sensors. Finally, he managed to get the whole system running live on a Raspberry Pi.
Now an rtl-sdr.com reader has written in to let us know that this concept has also been used before to create a 1 – 250 MHz FM transmitter using the Raspberry Pi and a program called PiFM. It uses the same concept of connecting a wire antenna to one of the GPIO pins but modulates the frequency using hardware on the Rpi meant to generate spread spectrum clock signals. It is claimed that it can transmit up to 50m away.
Below we show an example YouTube video of the Raspberry Pi FM radio transmitting to an RTL-SDR running HDSDR.
Adam, manufacturer of the LNA4ALL and LNA4HF is putting out an interest check for an ADS-B folded monopole antenna. The antenna can efficiently cover the 1030 MHz to 1090 MHz frequencies that are used by ADS-B.
The major advantage to Adams antenna is that it uses a DC grounded design, eliminating static build up problems that can potentially fry your LNA or RTL-SDR dongle.
If there is sufficient interest, Adam will sell the antenna for 20 Euros.
A new RTL-SDR Android app called SDRWeather has appeared on the Google Play Market. The new app allows you to listen to weather radio and decode EAS (Emergency Alert System) alerts. The app will only work in the US and Canada. More information about the app and its open source code can be found at http://sdrweather.thecongers.org.
This software along with a supported USB software defined radio turns your Android device to a portable weather radio.
Current Features:
* Listen to weather radio in the US/Canada.
* Decode EAS Alerts US/Canada
* Selectable Pre-defined Frequencies
* Alert Notifications
* Widget to display alerts
* Option to unmute audio when alert recieved
* FIPS and CLC Location Code Databases
* Event Code Database
* No internet connection required
Possible future features
* Switch to using rtl_tcp_andro
* Option to only show alerts if you are currently in the affected region
* Affected region map
