Archive for date: October 19, 2009

Using the 74HC240 in radio applications…

October 19, 2009 | General | By: Mark VandeWettering

There are a number of interesting radios based upon using things like hex inverters or octal drivers as both oscillator and amplifier. In digging around, I found the most common chip used in this application is the 74HC240. Here’s a link to a page which contains many interesting links: Testes com 74HC240 Another link to […]

DC40B, Day 4, and stupidity on my part…

October 19, 2009 | Amateur Radio | By: Mark VandeWettering

Well, over the weekend I completed the trial assembly of my DC40B. The voltages all measured out correct, but the oscillator seemed to not start reliably. It appears that the twin 47pf caps that provide crystal feedback may not be quite sufficient to reliably start the oscillator on power up. If I prod the base […]