KM1NDY

A Secret Little Adventure Ham Radio Blog

Debate: Does It Matter If The Secondary Windings Of A 49:1 Impedance Transformer (EFHW Antenna Unun) Change Direction Halfway Around? Does Bare Copper Wire Touching The Toroid Mess Things Up? Is “The Crossover” A Scam?

by KM1NDY

QUERY: Here are the results of a quick 49:1 [14:2 turn ratio] toroid transformer test. 1) Does it matter to transformer performance if the windings of the secondary change directions halfway through? [Answer: Yes]2) Does it matter to transformer performance if bare copper wire shorts to a ferrite toroid? [Answer: No]3) Does it matter to …

Continue Reading

“The Electronics Of Radio” NorCal 40B Transceiver Build Lab Notes: Problem 4 (Also An Interesting Way To Simulate Amplitude Modulation In LTspice)

by KM1NDY

This is a continuation of my solutions to the problems contained within “The Electronics of Radio” text by David B. Rutledge. These posts are probably only useful if you also are following along with the book and building the transceiver. [Update: The links to all problem solutions as I go through them will be posted …

Continue Reading

How To Build A Simple Single Transistor Amplitude Modulation (AM) & Demodulation Circuit (With Explanation Of How It All Works)

by KM1NDY

I ran into a roadblock. I am systematically going through “The Electronics of Radio” text by David Rutledge and answering the presented problems. Aside from buying the NorCal 40B transceiver kit, I have been able to use only equipment and components I have previously acquired for the first three problems. I hit a wall on …

Continue Reading