TYT MD-9600, add GPS later?

VK3KYY
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Re: TYT MD-9600, add GPS later?

Post by VK3KYY » Sun Dec 11, 2022 9:26 am

VK4MWL wrote:
Sun Dec 11, 2022 3:29 am
Hi Roger,

Can you please post some more details? GPS model and connection. I'm keen to do this mod.

Regards Mike
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


So...

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.

N1KY
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Re: TYT MD-9600, add GPS later?

Post by N1KY » Sun Dec 11, 2022 11:09 pm

Nice work Roger! Actually sounds like fun. I have a tube of MC1489s left over from the old days and they are always perfect for those unexpected RS232 <-> TTL conversion needs. :D

VK4MWL
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Re: TYT MD-9600, add GPS later?

Post by VK4MWL » Fri Dec 16, 2022 3:55 am

Thanks Roger for the details.

Here are the pin outs on a V2 md9600.

Red 3.3V
Brown TX from the GPS
Black GND

Mike
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VK3KYY
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Re: TYT MD-9600, add GPS later?

Post by VK3KYY » Fri Dec 16, 2022 6:53 am

VK4MWL wrote:
Fri Dec 16, 2022 3:55 am
Thanks Roger for the details.

Here are the pin outs on a V2 md9600.

Red 3.3V
Brown TX from the GPS
Black GND

Mike
Thanks for the photo.

I used a different pad for GND, but the others are the same.

I use hot glue to hold the wires to the PCB to act as strain relief, as I am always worried about pulling pads off PCBs.

Did you drill a hole in the back section of the front module of the radio, to exit the wires?

UA0LMC
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Location: Vladivostok, Russia

Re: TYT MD-9600, add GPS later?

Post by UA0LMC » Fri Dec 16, 2022 11:43 am

VK4MWL wrote:
Fri Dec 16, 2022 3:55 am
Thanks Roger for the details.

Here are the pin outs on a V2 md9600.

Red 3.3V
Brown TX from the GPS
Black GND

Mike
As far as I can see, built-in GPS module pin 6 (Vbat) and pin 8 (Vcc) are in parallel with no battery backup - so I expect the problems similar to RT3s, where every GPS on/off cycle causes a built-in module full reset and subsequent cold start.

VK4MWL
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Joined: Mon Jun 01, 2020 7:52 am

Re: TYT MD-9600, add GPS later?

Post by VK4MWL » Fri Dec 16, 2022 11:07 pm

Here are some more details.

GPS is similar to https://www.aliexpress.com/item/3283434 ... 1802ejNRic

I will use an external antenna, photos show the SMA plug in the side of the front panel. Hole is just big enough to fit the SMA female connector.

GPS board is held in with hot glue.

Roger. I forgot to put some hot glue on the wires. Good idea.

Mike.
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VK4MWL
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Joined: Mon Jun 01, 2020 7:52 am

Re: TYT MD-9600, add GPS later?

Post by VK4MWL » Fri Dec 16, 2022 11:13 pm

UA0LMC wrote:
Fri Dec 16, 2022 11:43 am
VK4MWL wrote:
Fri Dec 16, 2022 3:55 am
Thanks Roger for the details.

Here are the pin outs on a V2 md9600.

Red 3.3V
Brown TX from the GPS
Black GND

Mike
As far as I can see, built-in GPS module pin 6 (Vbat) and pin 8 (Vcc) are in parallel with no battery backup - so I expect the problems similar to RT3s, where every GPS on/off cycle causes a built-in module full reset and subsequent cold start.
Yes I think you are correct. The GPS board I used has a backup battery so the acquisition using an external antenna was pretty quick.

VK4MWL
Posts: 17
Joined: Mon Jun 01, 2020 7:52 am

Re: TYT MD-9600, add GPS later?

Post by VK4MWL » Fri Dec 16, 2022 11:52 pm

Should the GPS also set the time on the Radio?

VK3KYY
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Re: TYT MD-9600, add GPS later?

Post by VK3KYY » Sat Dec 17, 2022 5:50 am

VK4MWL wrote:
Fri Dec 16, 2022 11:52 pm
Should the GPS also set the time on the Radio?
I did not test this, but it should be setting the time

VK3KYY
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Re: TYT MD-9600, add GPS later?

Post by VK3KYY » Sat Dec 17, 2022 5:55 am

VK4MWL wrote:
Fri Dec 16, 2022 11:13 pm
UA0LMC wrote:
Fri Dec 16, 2022 11:43 am
VK4MWL wrote:
Fri Dec 16, 2022 3:55 am
Thanks Roger for the details.

Here are the pin outs on a V2 md9600.

Red 3.3V
Brown TX from the GPS
Black GND

Mike
As far as I can see, built-in GPS module pin 6 (Vbat) and pin 8 (Vcc) are in parallel with no battery backup - so I expect the problems similar to RT3s, where every GPS on/off cycle causes a built-in module full reset and subsequent cold start.
Yes I think you are correct. The GPS board I used has a backup battery so the acquisition using an external antenna was pretty quick.

The module I am using has its own backup battery.

Also

I did not want a socket on the front panel, so I used a module with its own antenna, and I have a short length of wire protruding from the back of the radio.
With an inline socket.

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