uses a single IC to convert a noisy pushbutton switch signal into a clean pulse or a sustained push on-push off signal.
http://www.imagineeringezine.com/PDF-FILES/4013cir.pdf
Commercial antenna tuners use unbalanced circuits such a Pi-, T-, or L-network to match unbalanced loads to 50 ohms for our transmitters. A simple way to include the capability to handle balanced loads is to include a balun somewhere in the circuit.
http://fermi.la.asu.edu/w9cf/articles/balun/
The purpose of QEX is to: 1) provide a medium for the exchange of ideas and information among Amateur Radio experimenters 2) document advanced technical work in the Amateur Radio field, and 3) support efforts to advance the state of the Amateur Radio art.
http://www.arrl.org/qex/
Introductional citations and information about QRP and PSK31.
http://www.qsl.net/ve6bpr/
http://www.intio.or.jp/jf10zl/swrk.htm
commercial tube amplifier.
http://www.tanker.se/lidstrom/quad22.jpg
Varactor diode provides temperature stability for FM quadrature demodulator.
http://members.tripod.com/michaelgellis/quaddet.html
[commercial - Win95/98/NT] Image restoration program, it can restore and enhance defect images (ex. out of focus and noise).
http://www.quantimage.com
use this to phase two antennas together for increased gain.
http://www.qsl.net/n9zia/wireless/appendixF.html#6
Here's a fun little project that can make big, fat, noisy sparks at least 2 inches long, and can be built very quickly and cheaply.
http://www.electricstuff.co.uk/marxgen.htm