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/

Optical test

Moving on with the tests on my latest lens the Samyang 500 mm f/6.3, here is a very objective comparison to give an idea of the level of magnification and optical performance this cheap lens is capable of.