Bob's DIY Homebrew Projects

I do like to build stuff.  I also like to share project details and give away finished projects (like kits and coasters for use as door prizes at our club meetings, for example).  And, in the true sense of open source, I like to benefit from those before me and pass on information to those that follow.  So, for anyone who is the least bit interested, here is a starting point for a collection of projects that I have done.  Enjoy!


AD-8307 Power Meter
I use this little power meter in series with a 5 Watt 30 dB attenuator to measure final output power on HTs, QRP rigs, and the like.  The noise power sits at about -70 dBm and the maximum input power is about +17 dBm, not a bad dynamic range for a unit in an Altoids box!  The board layout is done using the free version of Eagle (cadsoft.de) on my Linux box; files for the board, schematic, photograph, and a reference to the design article from QST follow below.
power meter photos
(Note: the label on the photo above should read AD8307 and not ~97)
Link to Eagle board layout
Link to Eagle schematic
Link to reference article

Time-Domain Reflectometer
This little circuit is used with an oscilloscope to find fault locations in long transmission lines.  This was just another fun little project the happens to fit in an Altoids tin.  The relevant files are linked in below.

tdr photo
Link to Eagle board layout
Link to Eagle schematic
Link to reference article


Electronic Load
If you have never taken a look at the web site of Paul Wade, W1GHZ, located at http://www.w1ghz.org/small_proj/small_proj.htm then you are missing out on some great information.  I built the electronic load he documents at http://www.w1ghz.org/small_proj/ps_load.zip and have been using it ever since.  Thanks, Paul!  Here's a photograph and the document I generated for our local club, NFARL, that describes the project: DIY_elec_load_02.pdf.

e-load photo


Low-Cost Paddle for the FT-817
I designed a little paddle for use with the FT-817.  When used with the internal keyer, this little gadget works just fine.  The idea here is to simplify, simplify, simplify -- by doing this the parts are cheap and the function is straightforward.  Paddle pieces are cut from a single piece of single-sided paper-epoxy circuit board.  This board material is much easier on the 0.040 inch end mill used to cut out the pieces than is a glass-epoxy board.  This project is done on the CNC minimill, of course -- it even cuts the mounting holes.  A piece of Corian is machined to mount the paddle to the 817 using the carrying strap holes -- and, you can still use the strap.  Here are some photographs of the paddle.

bobskey pcb photo        bobskey photo










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Originated 2010-01-15