TYT MD-9600 / Retevis RT-90 and GPS

ve2wkr
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Location: Silverthorne, Colorado, USA

TYT MD-9600 / Retevis RT-90 and GPS

Post by ve2wkr » Wed Sep 14, 2022 5:12 pm

HI! I wanted to get some clarity on the GPS support on this radio.
I have a MD9600 V4A without GPS, and a V5 with GPS. The V5 has GPS written on the board, but I cannot easily spot any other extra components. Nor can I spot any software behaviour difference. (I have not put the V5/GPS outside yet) Both are loaded with OpenMD9600 2022-07-28 build.

What would be different in the "Radio Info" menu when there is a GPS receiver in the radio ?
Long Press D then B on the microphone does not seem to have any effect, is this the correct key sequence to set the received GPS location?
What does the little flashing icon in the middle of the "Radio Info" menu mean ?
Does the GPS use the radio UHF connector though a high pass filter, or does it have a small internal antenna somewhere ?

73's
Luca
VE2WKR/W0

G4EML
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Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by G4EML » Wed Sep 14, 2022 6:42 pm

Hello,

The GPS module is fitted in the front panel with its own antenna. You won't see any difference on the main board. There is no method of fitting an external antenna to the radio, although it would be possible to unplug the internal antenna and run a cable to outside.

If the radio has a GPS module fitted it should be automatically detected and an extra page will appear in the Radio Information menu. this is between the Location and Temperature screens and has the Title 'GPS', it shows the received position, received time, and the number of satellites in view.

The GPS receiver is not that sensitive, so will probably not work correctly indoors. However the page should still be displayed and will show incorrect position and time. When it shows a good position you can transfer that to the radio by long press D followed by B. That position will then be used in the satellite calculations.

The blinking indicator at the centre bottom of the display just indicates that there is more than one page of information available.

Colin G4EML

ve2wkr
Posts: 65
Joined: Thu Oct 22, 2020 11:29 pm
Location: Silverthorne, Colorado, USA

Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by ve2wkr » Wed Sep 14, 2022 11:23 pm

Hi! Colin,
I opened the radio front section to verify that there is a GPS inside (not just outside fake labels). It appears that there is a wire going to a small GPS antenna inside the case.
The front board says "Key-V6.0180119" , and I can see an H210 GPS chip on it.
IMG_20220914_165205_901_small.jpg
IMG_20220914_165205_901_small.jpg (28.06 KiB) Viewed 1916 times
(sorry for the low res picture, but the board allows very small files only)

Is this supported ?
Thanks,
Luca

G4EML
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Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by G4EML » Thu Sep 15, 2022 5:38 pm

Hello Luca,

Yes it should work. However I don't think we have ever tested a V5 radio with GPS. None of the developers have one. There may be a hardware difference that we are not aware of.

Just to confirm, are you saying you do not have the GPS page in the radio information menu?

Colin.

ve2wkr
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Joined: Thu Oct 22, 2020 11:29 pm
Location: Silverthorne, Colorado, USA

Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by ve2wkr » Thu Sep 15, 2022 8:07 pm

Yes. That is correct.
I do not have a GPS page in the radio info screen. The radio behaves exactly as the V4A without GPS.
73's
Luca

VK3KYY
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Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by VK3KYY » Thu Sep 15, 2022 9:11 pm

Dones the GPS menu work in the official firmware?

I have a retevis handheld which has a similar looking GPS module but the official Retevis firmware does not recognise that the radio has GPS, so I think the GPS may be defective

Note. This is not on MD9600 etc, but TYT and Restevis radios are made in the same factory

G4EML
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Joined: Sat Nov 16, 2019 10:01 am

Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by G4EML » Thu Sep 15, 2022 10:33 pm

The module is a different part number to the one used in the V4 radios (JS-M710). From your picture the PCB layout appears to be the same but maybe it's not 100% compatible. That would seem unlikely as most GPS modules output the same NMEA data by default. I guess it's possible that the baud rate is different.

Colin.

VK3KYY
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Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by VK3KYY » Fri Sep 16, 2022 3:14 am

Update.

It looks like the GPS in my retevis radio is not sending the same data format as in the TYT radios

The GPS module is now working if I reinstall the official firmware, but not using the Open firmware.

I'll need to do some research to see if the problem is just the baud rate, but it could als be the data format. :-(

VK3KYY
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Location: Melbourne, Australia

Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by VK3KYY » Tue Sep 20, 2022 11:48 am

ve2wkr wrote:
Thu Sep 15, 2022 8:07 pm
Yes. That is correct.
I do not have a GPS page in the radio info screen. The radio behaves exactly as the V4A without GPS.
73's
Luca
I think we may know why the GPS is not working

The newer radios support not just the USA GPS network but also Chinese and Russian etc satellites, and hence send slightly different data sequences

I may need to send you a Debug verison of the firmware which writes the incoming GPS data to the COM port of the radio, to confirm what NMEA data sequences the GPS module in the newer radios produces

ve2wkr
Posts: 65
Joined: Thu Oct 22, 2020 11:29 pm
Location: Silverthorne, Colorado, USA

Re: TYT MD-9600 / Retevis RT-90 and GPS

Post by ve2wkr » Tue Sep 20, 2022 4:36 pm

Sure, The radio is still on my bench, so it's easy to test it.
Thanks.
73s
Luca

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