Kenwood TM-D710A GPS mod.

 Kenwood TM-D710A GPS mod.

Another copy of someone else's work...

I have the older non built in GPS D710...I had been using various external devices...but hated setting them up when using radio in a different vehicle.

In my case that different vehicle was used for 100 mile bicycle race support.  This year the bike race organizers incorporated APRS as an additional way to see where the support vehicles were currently located.   I didn't bring my external GPS, and my HT couldn't hit most of the APRS Igates...so I couldn't really participate in that...just had to use old fashioned location reports.

I started looking at the subject again, and there were no inexpensive, simple solutions to adding GPS...and most were no longer available or required out of date, and somewhat unavailable hardware.

Then I found this article.

 https://mythopoeic.org/tm-d710-internal-gps-de-nf3h/

It had all the info I needed...but I found some more references just to make sure.

Such as... https://yo3hjv.blogspot.com/2010/01/oem-gps-inside-tm-d710-front-panel.html

I used the Sparkfun GP1818  https://www.sparkfun.com/products/19166

It can take up to 5v VCC, so no regulator is required to step down to 3.3v

The serial output is 3.3v so I inserted the signal on the output side of R47.  Intially I had a 1k resistor from the GPS TX output to that point after R47...but wasn't getting a signal, then realized the output was only 3.3v without a resistor.

I recommend finding the service manual for the radio to locate the 5V power source and R47.

I have a microscope for soldering, so it wasn't a big deal...but R47 is tiny and requries much care to solder to...I was using tiny 30ga or so wire and that was big next to R47.  My tiny (I thought) solder tip was the entire size of R47...and I have done quite a bit of pin by pin SMD soldering with that same tip...

I didn't have to modify the case at all...just double stick taped the module to the back case right next to the 'speaker' output.

Good luck.