A few days ago, W8DIZ made a post on qrp-l.org announcing a new addition to his RF Toolkits line. This one is a 5 watt CW amplifier using a push-pull 2SC5739 pair as the PA (my new favorite full QRP gallon transistor). I built my own version of the circuit using parts that I had… Read More W8DIZ 5 Watt CW Amplifier
Here it is, a completed version of the simple discrete component code practice oscillator that I promised. I tweaked the circuit just a little bit and made a Manhattan layout that will enable the CPO, a 9 volt battery, and all of the required controls to fit into a standard sized Altoids tin. This CPO… Read More NT7S Code Practice Oscillator
I finally got a few days of decent sleep (decent meaning more than 4 hours), so I had a little energy to work on the simple DC transceiver. A few days ago, I got the remainder of the audio chain working. The emitter follower on one of the outputs of the differential mixer was yanked,… Read More Progress is Made
Yes, its a post about another simple, low-performing direct conversion receiver. However, I think that this one is slightly unique. I was inspired to give this a try based on the Flea minimalist transceiver that was introduced on the EMRFD Yahoo group. These little rigs are fun to build in an evening, but just how… Read More Yet Another DC Receiver
Here’s quick update to post the schematic of the code practice oscillator that I mentioned previously. As you can see, I just paired a twin-T sine wave oscillator with a buffer amp that feeds directly into headphones. The twin-T provides plenty of voltage, so the buffer is all we need to provide enough current to… Read More Preliminary CPO Schematic
I know that the blog updates have been a bit light over the last week or so. Although we have been in our new house for three weeks now, it seems like the chores just keep piling up. However, I have done a little bit of work in the homebrewing department. Inspired by messages from… Read More Back to Basics
A few different things have conspired to bring me back around to finish up the documentation for the Willamette, as well as forcing me to re-examine a few elements of the rig design. One of those things was an e-mail from AA0ZZ (really cool to hear from the designer of the PIC-EL and the IQPro)… Read More Another Look at the Willamette AF Filter
Today I finished construction on the circuitry for the RMS-to-DC converter described on the October 1992 QST article by W0IYH on measuring receiver performance. This is an article that I found on the EMRFD CD when I was searching for information on measuring the noise figure of amplifiers and receivers. I didn’t find the article… Read More W0IYH RMS-to-DC Converter
This morning we had the first Portland-area version of the Pie & Coffee, which we have informally dubbed the Eggs & Coffee since we are meeting at breakfast time. The meeting (and I use the term informally) was at the Peppermill restaurant in Aloha. In attendance was Dave W8NF, Carl WS7L, and myself. Not a… Read More Inaugural pQRP Portland Eggs & Coffee
Even though a homebrew return loss bridge is a relatively simple piece of gear to build, I’ve never gotten around to building one until now. Which is truly a shame, and something I don’t really have an excuse for, except perhaps laziness. I’m excited to add this essential gear to my stable of test equipment,… Read More Dual Gate MOSFET Investigations – Return Loss