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.

Traveling

Satisfaction with the 500mm reflex lens increases as I explore its potential in different situations. This time I took a number of shots holding it by hand during an afternoon next to the Lisbon international airport main runway. It was quite a challenge because of the moving targets, the lens being a pain to focus, and the fact that the camera was being held by hand. But the results seem to tell the rest...

To finish this topic full circle, here is a bit of cruise ship spotting, from the comfort of my balcony. These photos and videos were taken with a tripod and the 2x teleconverter added, resulting in a focal length of 1000 mm:

World Photography Day

Coincidentally, after having purchased an exotic lens for my camera and some days of wait for the F-Mount adapter, yesterday during the World Photography Day, I finally managed to test the lens. Aware of the shortcomings of this lens, still I was very pleased with the results, which I must say, open doors to different types of photographic work.

The lens is a Samyang 500mm f/6.3 mirror prime:

Reflashing a quad ESC to BLHELI firmware in an attempt to solve pancake motor cogging issues

Ever since I've switched motors and ESC's on my "primary" quadcopter, I have been running on problems keeping it reliable. Every now and then it would crash, once because of a motor connection that got broken, and other times in a unpredictable manner without  a cause that I could identify.

Teardown of a laser printer

In this age of mass consumption  and programmed obsolescence, it is not surprising that a few years after you shell out money for a printer, the availability of its consumables starts to decrease, followed by an increase of the associated price.

Gimbal finally onboard

After a long wait and a hassle with a chinese seller, finally I could but together the gimbal, flash the board with Brugi (Martinez) and do some tuning and testing.

While a first flight have not yet been done, manual handling with rough attitude change movements shows that the gimbal seems to respond pretty well and no vibration could be perceived in the video at 1080p.