Listening to Digital Radio Mondiale

The versatility of the Software Defined Radio doesn't seem to have boundaries. While exploring the HF bands, I tried to decode the occasionally received signal from Vatican Radio (http://en.radiovaticana.va/), which as of this writing was the only station I could identify as sometimes transmitting in DRM.

SDR - going higher in the wavelengths

While a 22 - 1400 MHz band coverage is pretty cool (given the price of the hardware), there is still more beyond (and below) these bands. In particular LF, MF and HF bands are interesting for a number of reasons:

Again with the SDR (Software Defined Radio) craze

After I bought my first RTL-SDR dongle (regarding which I made this post covering APT satellite (weather) image reception: http://creationfactory.blogspot.pt/2013/03/receiving-weather-satellite-images-with.html ), it's been sitting on the bench without much use. More recently I found extra stuff that could be interesting to take a look at, such as ADS-B reception (decoding commercial aircraft transponder signals) and less earthly things such as a doing some radio-astronomy, which includes for example trying to detect the 1420 MHz hydrogen line RF signal emitted from within our galaxy (it's a very exact frequency almost as accurate as our atomic clocks).

http://www.rtl-sdr.com/low-cost-hydrogen-line-telescope-using-rtl-sdr/

Receiving weather satellite images with cheap hardware

Before the Internet, anyone willing to independently obtain satellite imagery from the source would need to buy expensive equipment capable of decoding the analog slow scan video images transmitted by weather satellites  such as the NOAA APT ones. Today there are four of these NOAA satellites still operational, the NOAA-18, 17, 15 and 19. All of these are sun-synchronous satellites, which means these orbit the earth at around 800 Km of altitude and cross every latitude at approximately the same mean local solar time for each pass. This kind of orbit is useful because of the consistent illumination (by the sun) of the target upon each pass.

Decoding ACARS transmissions

Just as with other radio related hobbies, this is quite an interesting one:

Long-haul WiFi - new developments

Returning to the WiFi topic, here is the new antenna development that I had promissed in the early post, once the dual "cantenna" design was finished.

The dual cantenna is quite efficient, as I realized by connecting it to reasonably distant access points (in excess of 200 meters, with many obstacles between, including houses). By verifying the antenna efficiency was the expected, I assumed that in better conditions the range could be far greater, by establishing a link between two antennas of this type or other type of optimal configurations.

However, I knew I could push it a little further, so I decided to buy a 12 euro 45 cm dish from a regular satellite TV system, and the materials to build a biquad feed. I installed the dish on top of the tripod used for the cantennas, and attached the biquad feed (built according to these instructions) to it: