This is a updated collection of easy to build projects for radio amateurs and swl's.
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.

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