Thursday, October 1, 2015

SNA jr Re-build Updated 11/9/2015

There is a upcoming 'Makers Fair' in Atlanta, and several of the local Ham Radio clubs are going to have a display there.  They will demo some equipment and modes of operation. There will also be  several hand's on activities for the attendees. 
I decided to rebuild the SNA Jr. as part of the exhibit. I redesigned the circuit board, making it a little larger to make it easier to build.  Being larger it will no longer fit in the Altoids tin, but I found a metal Crayola Crayon box that was the right size.
I also found a nice small 12 V battery pack with charger on e-bay, they are available in several amp hour ratings.  It is just the right size to fit under the circuit board.  It has a built in On/Off switch and  a separate cable with the charging connector, which makes it very easy to build into projects that are battery powered.

Since this will be a show and tell event, I needed to make it "pretty".  Cutting the required holes in the lid of the tin, caused the metal to deform around the cuts. To make it smooth and sturdier, I glued a piece of .020" circuit board material on top of the lid, and filled in around the edges with some auto body filler. After a paint job, I applied some laser printed decals for labels. I also printed a fake bezel to put around the LCD display.

Along with the new circuit board, I also made a new RLB board that will connect directly to the SNA instead of having to use cables.

Here is a picture of the finished unit with the attached RLB.
It shows a normalized scan of my 80-40 meter  dual band dipole antenna.  Using a RL-SWR table lookup, the  SWR values are the same as when I scan the antenna with my FoxDelta Antenna Analyzer.

I have placed all files  necessary for building
including Eagle files and toner transfer image 
 in the following dropbox


  1. That looks really nice DuWayne. Well done indeed.
    Tony G4WIF

  2. Beautiful job DuWayne. Professional!!

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  4. Beautiful project.
    Can you please post the updated schematics (higher resolution display) and firmware?
    What is the part number of the display?
    Victor - 4Z4ME