A place for me to share information about my latest Ham Radio and electronics projects.
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.
12/3/16 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 https://gerryk.com/node/57
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. Tony http://www.fishpool.org.uk/snajr.htm
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
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.
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: https://www.dropbox.com/s/9kr00j6oad5nu0w/2017-06-13%2020.08.35.jpg?dl=0 I connected In to Out using a straight-through cable and swept again, giving this: https://www.dropbox.com/s/ginjlwmwrcpfz6o/2017-06-13%2020.09.24.jpg?dl=0
Is there some calibration I am missing?
I haven't soldered any shielding over the AD8307 yet... would that make much difference?
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 duwayne@kv4qb.us
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 Gerry
Working well now DuWayne... thanks for the design & the assistance. Here are some pics. Sweep of filter: https://goo.gl/photos/hRVjKcbi1MvP7Nx66 https://goo.gl/photos/bSyofH56GyyGZDXSA With RLB in situ: https://goo.gl/photos/PBpHXBysRtH5gNW26
Hi DuWaine,
ReplyDeleteI 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
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.
ReplyDeletehello friend of Pete ;) ;) do you have some pcb s for sale off sna jr ii ?
ReplyDeletethanks in advance ...9a3xz,Mikele
Hi DuWayne...
ReplyDeleteI 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:
https://www.dropbox.com/s/9kr00j6oad5nu0w/2017-06-13%2020.08.35.jpg?dl=0
I connected In to Out using a straight-through cable and swept again, giving this:
https://www.dropbox.com/s/ginjlwmwrcpfz6o/2017-06-13%2020.09.24.jpg?dl=0
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
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 duwayne@kv4qb.us
DeleteWell 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!
DeleteI'm an idiot, but thanks for not pointing that out straight off.
All the best
Gerry
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.
ReplyDeleteDuWayne
Working well now DuWayne... thanks for the design & the assistance.
ReplyDeleteHere are some pics.
Sweep of filter: https://goo.gl/photos/hRVjKcbi1MvP7Nx66
https://goo.gl/photos/bSyofH56GyyGZDXSA
With RLB in situ: https://goo.gl/photos/PBpHXBysRtH5gNW26
73
Gerry
These link not work: https://www.dropbox.com/sh/axyu01rttytlubg/AAB8UrBlqCEERAR1HFrHxpv1a?dl=0
ReplyDeleteThanks for letting me know, I thought I had corrected all of them just updated this one.
ReplyDeletehttps://www.dropbox.com/sh/u9axday3qj1lxsu/AADnBO1Txj-kDRSaof_lG3tza?dl=0