CW (Morse Code) with RTL-SDR
YouTube user Wolfgang Bleher shows in this video his reception and decoding of Morse code using an R820T RTL-SDR stick, HDSDR and CWSkimmer. He used a 2m Yagi as the antenna.
Tip: Effect of Power Sources on the Ham It Up Upconverter
The Ham-It-Up upconverter uses a 5V USB power input. I discovered that different 5v power sources can cause significant interference with this upconverter, and the same effect will probably occur in other upconverters as well.
When the upconverter was powered by mains power via a phone charger, the signals were almost completely drowned out in noise. Powering it with a PC USB port was better, but the PC USB power introduced some other strong noise sources. Powering it with a battery (used a mobile phone with OTG cable) was the best option. There are still some strong noise sources present, but I can probably solve them with better shielding.
Click continue reading to see some comparison images.
Receiving SSTV with RTL-SDR
Over on the Radio Antics blog fellow RTL-SDR enthusiast Andrew has been using the RTL-SDR to receive Slow Scan Television (SSTV) amateur signals. SSTV is a method ham radio enthusiasts use to send small images to one another. The images often contain their ham call sign overlaid on the image.
Andrew was able to receive several SSTV images using an R820T dongle tuned to the 27 MHz (11 meter) band. He also used a Funcube Dongle+ and got similar results.
Check out his post for some of the images he received, and his video below for an example of the receiving process.
Portable RTL-SDR Running on Raspberry Pi
Over on Reddit user olgierd has posted a video on this thread showing his work on developing a portable software defined radio based on an RTL-SDR R820T, the rtl_fm software and a Raspberry Pi with LCD screen. The software is based on rtl_fm which has the capability to demodulate FM/AM/SSB signals. His video shows him tuning to various signals using a tuning knob.
Note that his setup is capable of playing the audio, but it is not shown in the video as he only had earbuds connected. In the future he hopes to make it more portable by adding a li-ion battery.
RTL-SDR Tutorial: Receiving Weather Balloon (Radiosonde) Data with RTL-SDR
Around the world meteorological weather balloons are launched twice daily, and continuously transit weather telemetry to a ground station using something called a radiosonde. The RTL-SDR software defined radio combined with a decoding program can be used to intercept this telemetry, and display it on your own computer. You will be able to see real time graphs and data of air temperature, humidity, pressure as well as the location and height of the balloon as it makes it's ascent.
Note that if you are in the USA, then this tutorial may not be applicable for you as different radiosondes are used. Instead have a look at this post which shows how to use the SkySonde software from NOAA. You can also try an alternative command line based decoder called RS available on GitHub.
This tutorial is also applicable to other software defined radios such as the Funcube dongle, Airspy, HackRF, BladeRF or even hardware radios with discriminator taps, but the RTL-SDR is the cheapest option that will work.
Examples
In this example YouTube user Superphish shows a radiosonde being received and decoded using a RTL-SDR, SDRSharp and SondeMonitor.
How to Calibrate RTL-SDR using Kalibrate-RTL on Linux
YouTube user NeedSec has posted a good tutorial video showing how to use Kalibriate-RTL, a program used to determine the frequency offset error of your RTL-SDR dongle. Every RTL-SDR dongle will have a small frequency error as it is cheaply mass produced and not tested for accuracy. This frequency error is linear across the spectrum, and can be adjusted in most SDR programs by entering a PPM (parts per million) offset value.
Kalibrate is a Linux program that uses GSM mobile cell phone base stations to determine the PPM offset, by using the GSM signals own frequency correction bursts. See the tutorial video below.
RTL-SDR Antenna Adapters
YouTube user Eric William has posted a useful video explaining the different types of antenna adapters he had to buy (all for under $10) to connect his RTL-SDR (E4000 and R820T) and Ham-it-up upconverter to his antennas.
SDR Touch Updated to Version 1.5
Version 1.5 of the popular Android based RTL-SDR software, SDRTouch has been released.
This new version adds presets, which is useful if you intend to use SDR Touch as an in car Android based radio.
The DMCA claims made on the software earlier also seem to have been resolved, meaning that SDR Touch can be obtained from the Google Play market once again.
