Monday, April 26, 2021

On the air

 Wanted to take my new paddle out for a spin, so broke out the QCX.  Tried calling for a while, but no takers.  The only people I was hearing were *really* fast or they were far away.  Ho hum.

I got three spots on reverse beacon network.  Had hoped I'd get more.  So broke out the GPS board and tried to see who could see me on WSPR.

Amp success!

 Playing around with the amp again from the other day, but this time *with* power to the driver...

And I'm getting a solid 5w out!  Exciting result!  Now, mind you, in LT Spice it was showing like 17W out, but I'm still excited with the result.  

Board is extremely messy, and wires are all over the place.  Need to decide if I want to clean this up and make it more permanent or not.  Also want to wind the QRP Labs LPF (as opposed to using the cwaz one I made years ago).

Also, isn't the red LED fun!

Saturday, April 24, 2021

New paddle

 I 3d printed a new paddle.  Am pleased with it.

Here is the old/new together.

I am trying to make an ESP32 interface so I can do BLE to my iPhone so I can use it when I'm practicing on Morse-It, but so far it hasn't worked.  I managed to get it to be recognized on the wife's Windows laptop, but not on the iPhone/Mac.  I finally downloaded a program called "BLE Scanner", at which point I managed to get it to pair, but still can't get it to work with the morse program.  :/


Is working now!  Still not sure why it wasn't showing up initially.  But the issue with sending seemed to be the 'delay' I had in there.  A longer one let it work, but then wasn't response enough.  (Only had the delay due to the example in the library I was using.)  Ended up rewriting using the debounce2 library, and am happy with the result.

Code is here

Now just need to design a box to print, etc.  May try to use a rechargeable battery I have to make it more portable.  (The Adafruit Huzzah32 has a built in LiPo charger with undervoltage protection).  All in all, result!

Playing around with a different irf510 setup

 Just wanted to get back to building again, so threw together something from a couple of sources.  Basically trying to bring up the Si5351 voltage to something, then put into a totem pole driver, and then into an IRF510.  In LTSpice it is working great (17w), but on the bench, not so much (1.5w).  The first driver section gives me what I want by itself, but when I put the totem pole on, it drops, so the transistor isn't turning on/off as hard and wasting power in between.  Might try to poke some more later, but may try a different approach.

EDIT: the whole "sleep on it" thing wins again.  Woke up early the next morning with my first thought being "you totally didn't connect Vcc to your driver".  Sure enough, I was so focused on triple checking the IRF510, I missed the power to the totem pole!  So I'm surprised I was getting anything at all out of it, much less 1.5w!  :)

I also was driving with a sine wave instead of a square wave like I intended.  Will need to go over my build and test again when I'm able to focus better...

Tuesday, April 13, 2021

Gate Driver Woes

 So, my current theory is that I blew both sides of one of my drivers and one side of the other.  I had the suggestion on the QRZ forum to look at the waveform output without any transistors attached.  On one of them I don't see anything on either output.  On the other I see on the "top" output only.  So guessing I blew something up.  Hm.

Saturday, April 10, 2021

Homebrewed FT8 - Success!

Messed around with my antenna this morning.  It would look great, but pulling the feed line to the side a bit made the SWR go sad.  I brought it down and... just kind of messed with it.  Seems to be working now, but I'm not sure I could tell you what I did.  Tightening the N to BNC connection may have been it.

Anyway, had another go at it tonight, and managed to have a QSO!  WA6BJQ down south of me.  So exciting!  Also managed to get picked up all over.

Class D progress - April 10, 2021

 Based on some feedback from the QRZ forum, decided to move forward with a bifilar wound FT50-43 (six turns, 1:1).  Here is the result

Unfortunately, the smoke test let out smoke.  The bottom transistor (not pictured) blew.  I had wired the output transformer wrong, so thought that was the cause.  I put in another one, but it blew also.  My current theory is that I don't have enough decoupling capacitors in there, so the driver isn't able to drive the transistor well, so it is just staying partially on and burning up.  Will add some more and try again (though hopefully that works, because I only have one left!)

I wasn't sure about doing the IC adapters here (probably adds inductance and capacitance - hopefully not the problem I'm having), but being able to easily swap the chips is great.