This is a updated collection of easy to build projects for radio amateurs and swl's. See all my projects in the older posts down this blog.
Have fun.
73 John

Friday, December 21, 2012

Adjustable bandwidth

A  MAX7400 is an 8th order elliptical filter giving a 100 Hz to aprox. 3000 Hz tuning rate. It  means much more selectivity in many homebrew receivers.
The output can drive a LM386 . This filter is a must have for cw operators with simple ssb receivers.

Tuesday, December 11, 2012

LM386 on steroids

A problem with DC receivers is getting enough audio output. With a simple mod you can lift the gain of the LM386 to 34-74 dB .This is the ultimate mod for Pixie type transceivers. My Pixie needed a volume control after this mod  (-:

Disclaimer:I'm not responsable for any damage due to reproduction of my projects.


Solar data and HF conditions logbook