QST Letter to the Editor
As an avid builder of electronics, I look forward to the January DIY issues of QST. Imagine my dismay when I took a break to skim through it and managed to find typos in nearly every electrical schematic included in the issue. I hope that the ARRL's Harold Kramer "Inside HQ" promise of "working on a more structured approach to kits that will provide positive outcomes" in 2013 includes proof-reading the technical illustrations.
- "Cheap and Easy SDR" pg 34, Figure 10 - While the parts list and article indicate using an LM7805 voltage regulator, the schematic has it labeled the subtly different 78L05, which unfortunately has the opposite pinout. Pin 1 should be the output and pin 3 the input.
- "A Sampling Down Converter for Low Frequency Oscilloscopes" pg 40, Figure 2 - 7 turns on L1 is likely deficient to form a 22μH inductor. Luckily, the text clarified the actual number as 77.
- "A Sampling Down Converter for Low Frequency Oscilloscopes", pg 41, Figure 3 - The LM340-12 is shown with its input and output reversed. Apparently, it isn't a good month to be a voltage regulator.
- "Hand-On Radio" pg 64, Figure 3B - As shown, this would be very counter-productive to protecting your equipment. The NC and NO contacts on the relay should be reversed.