The Guy who Invented the LED

I'm a big fan of Ira Flatow's "Science Friday" radio program (recommended!)
This week, while digging through the archives, I found this gem:

http://www.sciencefriday.com/segment/10/12/2012/fifty-years-ago-a-bright-idea.html


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Bert's EMRFD Direct Conversion Receiver

Very nice Bert.  Sounds great.  I like the pill bottle coil core.  Lew McCoy used them in his designs. I do think that air core coils do provide better stability than ferrites or iron powder.   I kind of like the SW broadcast background music.  I also like the internal 9V battery.  Glad to see someone else resurrecting an old DC RX project.  


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

VFO for BITX 20/40

Here's the VFO I use in my BITX 20/40.   IF is obviously 11 MHz.   VFO normally tunes 3697-3859 kHz for 40 meters.  Switching in that 220 pf cap lowers the range to 3292-3189 kHz for 20 meters.  It workd very well.   The coil is wound on a cardboard tube from a coat hanger.  I will put this in the appropriate file on the BITX group site.    I like the 20/40 band combination:  Good DX possibilities on 20, with provisions (40!) for the low sunspot counts to come.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Manhattan meets Hyderabad: Pad Pattern for my BITX 20/40

A rough guide to how I laid out the isolation pads on my BITX 20/40 board.   The copper-clad board is 8 inches x 11 inches (22 cm x 28 cm).  I just cut out the pads as needed using tin shears and scrap pieces of copper clad board.  Gorrilla SuperGlue is my preferred adhesive.  I will put this in the appropriate file on the BITX 20 yahoo group site.


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Our New Robotic Overlords

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Homebrew Blimp with paper-thin Arduino (Printoo)

More on Printoo (very interesting!):

https://www.kickstarter.com/projects/1030661323/printoo-paper-thin-flexible-arduinotm-compatible-m


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Hackers Recover 1960's Moon Pictures

http://www.wired.com/2014/04/lost-lunar-photos-recovered-by-great-feats-of-hackerdom-developed-at-a-mcdonalds/

Thanks to Mark, K6HX, for alerting me to this wonderful project.   

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20