Friday, October 7, 2016

Another SNA Jr. lives UPDATE 3/3/18

I have been exchanging  e-mail  with Caglar TA2UH , concerning compile problems with the SNA Jr. he is building.  Only problem seems to have been the version of  the 'rotary' library he had been using.  After sending him the correct one, he now has his Junior working. .  It still needs to be put in a box and some accessories built, but from the picture he sent me it looks like everything else should not be a problem.

I just copied the correct version of library to the SNA Jr version II dropbox folder to help eliminate this problem for builders.

Just got some pictures of  Caglar's finished SNA Jr with some accessories. Looks great, a lot of work with some hand tools to get it fit into a cast aluminum box.  

 And another of it in use testing a crystal filter

 ANOTHER ONE   10/14/2016

Just received an e-mail from Vincenzo IZ5GVP with some pictures of his version of the SNA Jr.  He also included an Arduino sketch with some of the additions he has made to the software.  I took a quick glance at it, and it looks very nice.  I will take a longer look  (with the help of Google Translate) and  see what I want to add to my version of the sketch.

When I did the latest version of software, I was in a hurry to get everything ready for FDIM.  I did not do much in the way of calibration, Vincenzo's sketch has some cal routines that I will defiantly have to look at.

And another one from John VK5COR, he made his own 2 layer board.  He said it worked but didn't look very nice. then he had a couple boards made.  Said they look a whole lot nicer.  He is now working on a box to put it in. 

It is very gratifying to receive e-mails with pictures of other peoples build of some of my projects.  Sometimes when you write a blog, you wonder if you are just wasting your time.  When you get pictures of other people building your projects, you know that what you have written is of interest to more than just yourself.  So please if you have built any of my projects please send a picture and I will put them in a Dropbox folder for all to see.

Update 3/4/17
Just found a Blog entry by Gerry with some pictures of his SNA Jr. build

Update 3/30/17
Just received a em-mail from John KG9DK   with a picture of his finished SNA Jr.  I have been exchanging e-mails with John for over a year now about the SNA and other topics. Nice to see he has his SNA finished, really like the work he put into the design of his front panel.

Update 3/3/18
I updated the link in the dropbox.   Also adding an additional link to ones that have been built.




  1. Hi DuWaine,
    I built the SNA Jr II on breadboard to see it working but it wouldn't work. I built it according to your published schematics. When I compared the schematics to the PCB layout I've found a possible error in the schematics: A0 of the display has to be connected to D10 of the Arduino and not D12 as in the schematics.
    After correcting the connection in the breadboard everything works perfectly.
    Victor - 4Z4ME

  2. Missed that when I had switched from the original version to the version II board. Wiring will work as is, you just need to change pin assignment in the sketch.

  3. hello friend of Pete ;) ;) do you have some pcb s for sale off sna jr ii ?
    thanks in advance ...9a3xz,Mikele

  4. Hi DuWayne...
    I realise you're not a tech-support service, but I was hoping you might be able to point me in the right direction. I built an SNA Jr II a while back but didn't really play with it until recently... I did an SWR sweep of an OCF Dipole, whiich I expected to have some dips in SWR, but it came back as flat SWR= 3.75:1 across the bands.
    I also did a sweep of a BPF I built and it looks like this:
    I connected In to Out using a straight-through cable and swept again, giving this:

    Is there some calibration I am missing?

    I haven't soldered any shielding over the AD8307 yet... would that make much difference?

    Thanks & 73
    / Gerry

    1. Gerry Looking at the second sweep, it looks like there is no input to the 8307 power meter. Sweep starts at noise floor, and goes up by the frequency correction in the software to account for the 9850 drop off. With no cable connected measure the input resistance of the power meter, should be 50 ohm. Connect your jumper and make sure you have continuity from rf out to rf in at the contact on the bard. Still having problems contact me directly at

    2. Well spotted... I had a look at the signal at each port and they were the same, so I worked in along the path until I saw 2 bare pads... I had forgotten that little inductor!
      I'm an idiot, but thanks for not pointing that out straight off.
      All the best

  5. Glad you found it Gerry. Let me know how everything works after you put in the little coil. Please send a picture if you can.

  6. Working well now DuWayne... thanks for the design & the assistance.
    Here are some pics.
    Sweep of filter:
    With RLB in situ:


  7. These link not work:

  8. Thanks for letting me know, I thought I had corrected all of them just updated this one.