Over on YouTube Adam Alicajic has posted a video showing how much a bandpass filter at the front end of an RTL-SDR can significantly improve reception. He points out that it is a myth that modern software receivers do not need preselector filters at the front end for best performance.
He tests the RTL-SDR with and without a front end 2m triple helical bandpass filter on a CW beacon at around 144 MHz. With the filter on there is almost a 10dB improvement in signal reception.
The PAL/NTSC analogue TV viewer TVSharp has recently been updated to version 1.2. This new version features an updated GUI as well as automatic frequency correction and automatic position correction. This may correct some of the scrolling and slanting problems seen in previous versions.
Word of warning: Chrome recognizes the download as malicious, however I have downloaded the file using FireFox and scanned it with Microsoft Security Essentials which found it to be clean.
The VHF Data Link mode 2 (VDL2) is a new transmission mode used on aircraft for sending short messages, position data (similar to ADS-B) and also for allowing traffic controllers to communicate to pilots via text and data. VDL2 is intended to eventually replace the standard ACARS modes. It is found at 136.975 MHz.
Recently, a wiki page explaining how to decode VDL2 using MultiPSK, Planeplotter and the RTL-SDR has been put up. MultiPSK is a sophisticated software program that can decode a wide range of amateur radio digital signals as well as several professional modes like VDL2. To decode most professional modes like VDL2 however, the paid version of MultiPSK is required, but a 5 minute per use trial of VDL2 decoding can be used for testing. Newer versions of MultiPSK can now even directly connect to the RTL-SDR dongle.
The wiki page shows how to set up the RTL-SDR dongle on MultiPSK to receive VDL2 signals, and then shows how to connect it to PlanePlotter in order to plot the aircraft positions on a map.
The BladeRF is a software defined radio that has transmit and receive capability. Over on his blog, Clayton Smith has recently posted about his experiments which involve using the BladeRF to transmit DVB-T digital TV on one laptop to another laptop running an RTL-SDR in DVB-T mode. This is one of the few applications where the RTL-SDR is used as a DVB-T receiver as it was originally intended. Clayton used GNU Radio, a DVB-T package for GNU Radio and some python scripts to create the BladeRF transmitter.
The newer Linux kernels have DVB-T support for the RTL2832U chip, so the latest version of Ubuntu 13.10 will be able to recognize the RTL-SDR stick as a DVB-T receiver easily. Clayton used VLC in Ubuntu 13.10 to receive the DVB-T signal transmitted by the BladeRF which was tested on the 70cm, 33cm and 23cm bands.
Webcam DVB-T TX by a BladeRF and RX by the RTL-SDR
Max/MSP is a graphical programming tool for creating music, sound, video and interactive graphics applications. YouTube user Tom Zicarelli has recently posted a video showing his test of a Max wrapper for rtl_fm, allowing an FM audio stream to be received and controlled in Max. Tom is also working on an RTL-SDR wrapper for PureData, another visual programming language aimed at artists. These wrappers will be useful for artists who wish to utilize RF in their projects.
Hak5 has recently posted another video continuing their easy to follow series on GNU Radio and the RTL-SDR. In this video they talk about Radio Data System (RDS) and explain how it is a digital signal that is embedded in broadcast FM signals. They then download GR-RDS, a GNU Radio based RDS decoder program and use it to decode a local RDS signal.
Decoding Digital Subcarriers with a $20 SDR, Hak5 1602
Adam the manufacturer of the LNA4HF has recently uploaded a video showing how to easily build an upconverter from the LNA4HF. The LNA4HF is a low noise amplifier intended for use with SDRs like the RTL-SDR. The video shows how to connect up two components, the Mixer and Oscillator which are required to create the upconverter.
It is important to note that different antennas will have different gain directionality, so your own experimentation may still be required for your own RF environment.
