I've found a good deal on a brand new MD-9600 & 30 amp power supply combo but the MD-9000 is not the model with GPS. I know that the GPS in the MD-9600s is not very good and chances are that I will never want it, but in the future if I change my mind is there a way to add it?
I'm almost certain that the answer is no but I just thought that I would ask.
But...! Can the FW be upgraded, despite very little memory left for new code, to use external GPS via USB?
Now we wait for developers to get the definite answer...
I believe that Roger is planning to try this at some point soon.
Its not going to be practical to support USB GPS modules, as this would require the firmware to be a USB Host, like a PC, and this is a totally different USB system than being a USB Client.
I'm not even sure whether the hardware USB port, in question, on the STM32 CPU supports being a USB Host.
The STM32F4xx has 2 USB ports, and possibly one is designed to be a USB Client and the other to be a USB Host.
We would not currently have enough space in the firmware to support both a USB Client USB stack as well as a USB Host USB stack, even if the hardware was capable of it.
My plan is to use a module that sends data at 9600 baud serial, and connect to the PCB, via a connector on the back of the radio, albeit there is not much space on the back panel.
The latest MD9600, seem to have a rubber plug, next to the fan, at the top, which I'm hoping to remove and then fit a 2.5mm stereo jack socket, but I'm not sure if there is room.
If not I'll need to run wires out the back to an inline 3.5mm stereo jack socket
The GPS module would need to be powered, so the connections would need to be Supply +, ground and Rxd. I'm not sure what voltage these modules take, either 3.3V or 5V.ve7mdt wrote: ↑Tue Nov 29, 2022 1:42 amThis is an interesting mod.
My Kenwood TM-D710A (not the G model) has a 2.5mm jack on the control head to connect to an external (not included) GPS (signal). Some people modified the head to bury it internally, but the antenna does not face up so it's not ideal. (The GA model has it built in inside the control head).
So this is a similar idea to the D710A. The jack supports TTL serial signal w/ TXD, RXD, and ground.
But plugging in a jack socket while the radio is turned on could cause problems as jack sockets short multiple connections when the plug is inserted, so there would probably need to be a resistor in series with the supply to prevent the supply getting shorted.
Very long story.
I wanted an extenal GPS module in a weatherproof box. Most of the ones I found online were USB, but the radio needs serial data
I eventually found a Serial RS232 GPS module on AliExpress, so I ordered 2 of them.
When they arrived, I tried connecting them to my PC via a USB to PC converter module, to test the data, but it didnt work.
After a discussion with G4EML, I checked the serial data using a scope and found it was 10V not 5V signal level and also the signal was inverted.
Looked again on AliExpress and found TTL Serial version of the same module , and ordered 2 of those.
As I'm impacient, I decided to break open one of the RS232 serial GPS modules, and see if I could tap into the data at TTL signal levels, and found that the module was not at all waterproof, and I could take the bottom off by undoing 4 screws
Inside the module was GPS module and a RS232 converter chip.
I unsoldered the Tx data wire and connected it directly to the output of the GPS module, after using my scope to find the TTL GPS serial data pin.
The data could now be seen correctly by my PC.
I initially intended to connect wires to the ribbon connector on the main PCB of the MD9600, but I realised that the 3.3V line was constantly powered on, and the GPS would be constantly powered.
So I disconnected and removed the front panel, took the front panel apart, drilled a hole in the back section of the front panel, for the GPS wires
I found the pads on the PCb where the official GPS module is mounted, specifically the +3.3V Gnd and the data.
Then soldered wires to those pads, and ran the wire back out through the hole I drilled.
I refitted the front panel, then ran the GPS wires acorss the main PCB, away from the RF side of the board, and on my MD9600 V5 hardware there is a rubber bung the rear heatsink, which I removed and fitted a small grommit in its place and rang the wires though the grommet.
I refitted the top of the radio and at the moment I'm using a 4 pin inline PCB connector for the GPS connections, but I will switch to a 3 pin inline socket when I get time to replace it
Look for a external GPS module that says its TTL Serial, NOT RS232
I have not received the second batch of gps modules which claim to be TTL so can't post a link until I receive and verify that they work.