A couple of weeks back I was toying with the idea of using the board i developed to use in a transceiver and programming the ESP32 to do WSPR. Initially i tried connecting the ESP32 to my home wifi to lookup the time from an NSP server etc etc but I had trouble with the ESP32 not connecting to my wifi.

After enabling better debug messages and doing some google foo searching for the answer, i took a good look at the debug messages and discovered that the brownout timer was being triggered because the voltage on the USB ports on the front of my machine was to low for it to be happy. Changed the cable and changed to a rear port and I was back in business.

Half an hour later i was watching wspr coming out of the SI5351a on the oscilloscope and i knew I was in business. Grabbed out a small PA and LPF, connected it all together and we were in business.

Power out of the PA going to my antenna is about 1W. Since I took the screen cap below, i have upped the voltage going to the PA to bring the output up to exactly 1W.


And as for whispering, we are whispering sweet nothings to all the usual suspects. I do not expect this to break any land speed records, but its been a fun exercise and now I am going to work on adding switchable LPF’s and ramping this up to 4 bands. I have 2 antenna here, one is a 40m dipole and the other is a tri-band trapped vertical. So having 4 bands running should be cake. I do have the boards for the LPF as well, i just gotta build them and code up the band switching.


Missing In Action?

Naaa I am still here I have just been taking a break and doing other things for a while. There is a lot going on currently and the world is a mess and I have been doing my best to avoid all of it. So what have I been doing? Well, iRacing for one, its a good time sink and an escape from the everyday, plus I used to be a racer all be it bikes, but always wanted to race midget speedcars and well now I can from the safety of my own computer screen.

I really needed a holiday, both from work and from amateur radio and so for the last 3 weeks I really have avoided both. Now i am refreshed and invigorated and its time to get back into some of the things piled up on my bench and then some more. The receiver part of the tranceiver is mostly working now, today i will get it all back together and give it a test this afternoon and I am also working on some code for a WSPR transmitter and i think i have it all working now and just have to design a PA board for it and its ready to rumble.

More to come.


More Receiver Work

So with the VFO and Audio board working i turn my attention back to working on the receiver. Now the first version of this was an unmitigated disaster. Clever me, always throwing caution to the wind used MMIC gain blocks for IF amps and had nothing but trouble with them oscillating and going bonkers. Well, this time I threw caution to the wind again and used high speed op-amps for the RF and IF amps. Everyone has done a 2n3904 IF amp and i could have done the same, but, lets try something different. And i could not be more pleased. Actually using op-amps might just become my thing LOL they are actually surprisingly easy to work with once you know what you are doing.


I have posted about this before somewhere on the blog, but this is the circuit I used after reading some app notes from one of the big manufactures. Non inverting, 50 ohms in and out impedance and thats about it really. Unity gain bandwidth of the op-amps i used is 380MHz and they are a 20 cent Chinese part.

Doing the initial alignment of VFO and BFO frequencies I had more probes up its cackler than an abductee at a aliens convention.


The mighty RF Explorer spec-an for the win getting the VFO frequency mixing with the RF input to be right smack center in the passband of the 500hz wide IF filter. Yeah its a CW rig this one.

VFO A is the IF frequency and VFO B is the BFO frequency.

And this is the 600hz tone out the AF port. Which will eventually get routed the audio amp that I actually short circuited while fixing it until it was broken. Actually, the AGC and the Audio filter circuits work just fine, its the AF amp i killed. Its just a matter of de-soldering the amp module and replacing it with one that works. Every day I am getting closer and closer to something that actually works good enough to use more than once.


Happy Easter


Chokies and Home Brew. That is the business, LOL. Currently working through some issues on the audio amp. Turns out I removed a DC blocking cap that was essential and had to cut some traces and add in a cap and bodge wire. Got an issue with the volume pot not adjusting volume, but I have a fix for it. And then it is on to adding in the receiver and seeing if it works, and I have some software issue with the real time clock i need to sort out. That is were we are at currently. 🙂


ESP32 With Dual VFO’s

Hey look, its a home brew radio post. HAHAHA. So i have settled into this whole locked down for corona virus nightmare and have sorted out most things and have a game plan for how life will go on for the next 6 months of lock down and no work. And because i have everything in order, i have slowly been getting the enthusiasm to get into building some of the stuff i have in the pipeline and seeing if it works.

I have shelved the tuner for now, i really am not sure about it and it or how to correct its problems, which are both design and code and have started on the second iteration of the universal control board. First time round all the audio stuff worked just fine, more or less, but there were some design issues in the micro controller side of things. Namely, i screwed up things pretty bad and destroyed the 2 older ESP32 Dev Boards i had here which meant redoing footprints and all the other exciting things.

Obviously not everything has gone smoothly this time either, turns out that i laid out the board with to use an L7833 3.3v regulator as I am using a L7805 5v regulator as well, you know bog standard parts everyone uses. But guess what, the TO220 3.3v regulators I had were 1117A’s and they have a different pinout. Turns out, getting an L7833 regulator in Australia is not as simple as it seems, I had to order them from Element 14 for way to much plus way to much in postage. But, it got the parts and well got to getting this thing working. Lesson learned.

On the board, we have an ESP32 micro controller, the little red daughter board is a shift register module, ESP32 is 3.3v logic and most of the crap hanging off it is 5V logic, thus the need for shift registers on the I2C lines. The fuse is there from another lesson learned from the previous version of this board where I turned the solder on the micro into lava HAHAHA. We also have 2 headers for LCD screens, 2 rotary encoders, SI3531A module, yeah still using modules because the 2 times i have tried to roll my own using bare components, they never worked, and finally a real time clock. There is also footprints for 5 buttons, one of which is a reset button for the micro, 2 banks of 5 pins for band switching and pads for a thermocouple for monitoring heatsink temp of the final PA.

A bit blurry, but this is the initial fire up to make sure that I had things working right. Not much use spending hours writing code if there is an issue on the board.

Here I am starting to make some progress on the software, which is pretty much a ground up rewrite of one of the basic VFO codes out there, I think if i recall right was a very early version of a VFO by Jason Mildrum NT7S

And finally, this is where I am at with this. All the buttons work, the rotary encoders work and both the displays work. The one thing i do not like about just about all the VFO codes out there is that they all follow the radix math method for setting the vfo increment value. I want to have a 500hz increment, and actually, when i start to build things for 2m FM i will want an 12.5Khz increment and the like. Now using radix math you only get to have things go up in orders of magnitude, 1, 10, 100 etc. So I changed how that all works and simplified things alot, by combining the increment and displaying into the one function that gets checks once per loop. I can now set my increments to whatever value I like to suit my purpose.

Finally before i close down this epic post, on Jason Mildrums etherkit github some people have reported issues with ESP32 and the SI5351A library. I am not having any problems at all here. Everything works as expected and there are no I2C glitches. Well, that was a manuscript, thanks for reading and I will catch you next time.




Toys For Kindy

So work wise I am not doing all that much. So the wife, who works in child care and is classified as an essential worker for the covid 19 response has asked me to make her some resources. I don’t mind and it have me a couple hours of doing stuff today other than watching the walls from within lock down. So i knocked up a set of letter disks and some boats. As i write this post, my wide is cutting out fabric and sewing some sails for the boats.


Its Always The Way

I have spent the last month worrying about my business, finances and not dying from The Rona. So yesterday I actually felt motivated enough to start working on a project I have had sitting here for some time. Got enough built where I could start testing things, turn on the PSU and it hooks up straight into current limiting. Hmmm, I have a short. So i go into diagnostic mode and start to deep dive.

It did not take me long to work out what the problem was, the regulator for the 3.3V supply rail used a different pinout than whats on the board. I had assumed that the 3.3v regs i had were all of the L78xx series, but they were not, somehow I had bought LD1117Vxx series which have a different pin out.

The only ones I can get locally in the same footprint are 50ma and I need a couple hundred ma. So i had to order from element 14 and they are god damn hopeless on a good day and do not expect to have parts for a week. I would have ordered from mouser, but i do not have the money to put in an order big enough for free shipping and I just dont need much at the moment.

The joys of home brewing HAHAHA. I now have hay fever like a MOFO and feel like i am dying. So I am going to dope up on phenergan and go to sleep for a few days HAHAHAHA. Too much information?