Archive for tag: circuit

M1KTA’s QRP ham radio blog: PTO VFO

January 28, 2010 | Amateur Radio | By: Mark VandeWettering

If you go back through lots of amateur radio designs, you’ll find many, many circuits that use the nearly uniquitous 365pf air spaced variale capacitors that were nearly ubiquitous up until about 25 years ago. In the last couple of decades however, they have become like Avatar’s unobtanium, seemingly impossible (or at least expensive) to […]

30m Subharmonic I/Q-SDR Receiver

January 4, 2010 | Amateur Radio | By: Mark VandeWettering

Over on NT7S’s Ripples in the Ether blog, he presents a link to a project by Joachim, DL1GSJ, a very nifty little SDR designed to operate near the 30m QRSS watering hole frequncy. It uses pair of subharmonic mixers, whose operation I admit I don’t completely understand, but I’m bookmarking the circuit for later consumption. […]