Catwalker

 I decided to take a breather from the SWR bridge and the swr sweeper to build this: it's my build of a "Duinovox" Basically an automated T/R switch for use with digital modes. The original design is by Kevin Loughin, KB9RLW. His blog is here: KB9RLW Blog.

Kevin's Youtube page is here: Duinovox KB9RLW.

Which is where I first saw it, not too long ago actually. The big difference between Kevin's unit, and the one I have built is that I designed a quick and dirty PCB in Kicad, then had it manufactured at OSH Park. (I hate point-to-point wiring) The board is not the prettiest I've ever designed, but it will do....

Here's my unit:

I also added an on-board regulated power supply, as I was going to keep my USB sound card external to the case I eventually put this into.

I will give a report a little later, plus, I will have a Rumble video up as well.

"Keep your stick on the ice, we're all pulling for you"

Red Green

じゃまた

 My other project, an SWR scanner, is built and working, well, sort of. There's an issue where it gives pretty much the exact same reading no matter the antenna hooked up to it. A dummy load should give a nearly flat response across the band, but it doesn't, same thing with a 50 Ohm termination, it's giving some mighty odd readings, so stay tuned for more troubleshooting.

Video of breadboarding.

じゃまた

 Well, the Stockton bridge and the Arduino work, but now, it's troubleshooting time. :/

The numbers coming out make no sense...

The SWR into a 50 Ohm dummy load is 1.0, which is as it should be, but the FWD and REV are way out of whack, the output for FWD should have been 5.0 and the Rev should have been near zero... FWD was 0.### and REV was up to 11.###

I think I know what's wrong, but, we'll see...

じゃまた

Well, time to start experimenting with software, first, the sketch for the Arduino, I found a project here which sort of suited my needs, but since I'm not using the LCD, I ripped out the display code. I'm also going to have to make a couple of other mods.

Here's the Arduino (That's a Sparkfun Redboard to one side) being experimented with. I currently have it set up with a small pot varying the voltages into the analog inputs, and it's working, now to try it with the bridge.

 

 

Stay Tuned ( :D )

じゃまた

 Well, it's been a while, finally got around to getting this soldered together and in the aluminium box. When I ordered the box, I didn't realize it didn't split in half, so, it was fun getting the small board in there. I'm guessing the box is designed for slightly larger boards, which slide into the slots. Oh well. It's together, now for the arduino (which is basically functioning as an a/d converter, the Pi (which will do the display) and software. This could take a while.

 

 

 

 

 

 

 

 

 

 

Later... :)

じゃまた

Onward and upwards! ;)

The next project is a QRP SWR bridge...
But, what's so special about that? An swr bridge? You may ask...
Well, nothing special about the bridge itself, it's a simple
Stockton Bridge based on this schematic:














The original article can be found at this link: SWR Meter


Which is why I haven't bothered covering the construction
of this part. You can see the completed board in the below
photo with a curious part.
 

 

 

You'll see a DB9 connector underneath the left SO239 connector.
This is going to connect to an Arduino, instead of an analog meter.
With the Arduino simply acting as an A/D converter with the
destination of the digital signal being a Raspbery Pi...

Stay tuned.

(See what I did there? ;) )

じゃまた

So, here is my clone of the Heathkit HD1416.
The construction was quite successful and works well, but,
the construction was so, so simple, I would be embarrassed if it didn't
work and work well. It just needs a case now.

 

じゃまた

Well, this is embarrassing! My first post of 2020 and it's April 24th!
Oops. Well, time for an intermediate project or two, before I carry on with the limited space antenna and figuring out just how well it's working.











This is a schematic of a Heathkit HD1416 Code Practice Oscillator.  I bought the actual kit around 1978, probably still have it somewhere, but packed away, and I needed a CPO in order to do some testing. So I decided to build one. I still have the complete manual (which is downloadable off the web - not from me - you can Google it.) This is the second clone I've built of this. I built one for a local ham (now long deceased) for him to give to a young fellow he was encouraging to become a ham.

The circuit is an astable multivibrator consisting of Q1 and Q2, the output being fed into a transistor audio amp, Q3.

じゃまた