EDIT 5/13/26 – I have 5 kits available, email me at kv6o@kv6o.com if you want one.
Looks like my last post was May 10, 2025, and today is May 10, 2026 – so at least I am consistent! I get a trickle of requests these days looking for kits, I just put together another 5 and need to order headers to make the kit complete, so I’ll hopefully have some to ship in a week or two. A few folks have posted asking, so I’ll send you an e-mail when I get the kits complete.
This PCB was designed in Eagle years ago, and I have been recently working in KiCAD on another project with Surface Mount Devices (SMD’s) and decide to import the DG5 project and see what I could do converting it to SMDs – mostly as an exercise. Doing some preliminary research, a Raspberry Pi RP2040 (32-bit dual-core ARM Cortex-M0+ microcontroller) might be able to process all 3 frequencies simultaneously – and at 40MHz plus, where the HET frequency is. This would eliminate the 74HC93 used as a divide by 8 pre-scaler for the HET, and the 74HC153 used to select between the VFO, CAR, and HET signals for measurement into the single frequency county on the ATMega328. IF I were do design this today, more modern microcontrollers would be the way to go here, but given the demand has tapered off, I don’t think I’ll go thru a full on redesign and rewrite of the code for 5-10 units a year. Besides, the current design works – even if it’s getting a little old. Heck, the TS-520’s are way older!
Thoughts? Anyone want to tackle this?
I think the thru hole version is going to allow more people to build kits due hesitation of some to the tiny surface mount parts. That being said, lot’s of thru hole components are being discontinued so things will change in the future. I was wondering if you have any instructions for fine tuning the side band indicator code on the DG-5 clone.
I don’t have any instructions, but the code is well documented. Below is the relevant part – you can adjust the frequencies used to make the USB/LSB/CW determination if needed. There is a debug mode that will display all of the measured frequencies via the serial port – you might want to start there to understand what’s happening. You’ll need a USB to FTDI board that you attached to the FTDI header, then issue “DEBUG1;” and it will serial print all the of the measured and calculated data.
// use the BFO (CAR) frequency to determine USB/LSB/CW
// In the TS-520S Service manual on pg. 6, it describes the frequencies used by the BFO for the different modes.
// It states, “Frequencies are 3396.5 kHz for USB, 3393.5 kHz for LSB, and 3394.3 kHz (receive) and 3395.0 kHz (transmit) for CW.”
// You might have to tweak these values for your BFO – this is a function that the origional DG5 didn’t do.
// If your Arduino’s crystal is off, you might be able to fix both using the correction factor (cf) variable in the “Frequency measurement variables” section
if (bfo > 3396000){
USB = true;
LSB = false;
CW = false;
mode = ‘U’;
}
else if (bfo < 3393500){ USB = false; LSB = true; CW = false; mode='L'; } else{ USB = false; LSB = false; CW = true; mode='C'; }
Thank you for the very detailed reply. I’m sure this will help builders in the future fine tune their units.