OpenGD77

VK3KYY wrote: ↑

Tue May 13, 2025 9:03 pm

I'm not sure which M10 generation modules would fit inside a dm1701.

Virtually all modules listed on AliExpress etc, as M10 generation have the same chipset in them

I use Quescan branded modules in my md9600, but other brands perform about the same.

I think the variation in performance is mostly related to the antenna size

I have read about your mod in the MD9600 thread. Does the M10 module still have a problem with baud rate?

KA1CM wrote: ↑

Wed May 14, 2025 12:48 pm

VK3KYY wrote: ↑

Tue May 13, 2025 9:03 pm

I'm not sure which M10 generation modules would fit inside a dm1701.

Virtually all modules listed on AliExpress etc, as M10 generation have the same chipset in them

I use Quescan branded modules in my md9600, but other brands perform about the same.

I think the variation in performance is mostly related to the antenna size

I have read about your mod in the MD9600 thread. Does the M10 module still have a problem with baud rate?

Other baud rates are now automatically detected on STM CPU radios, but not on the older GD77 etc radios.

However the RSSI etc screens don't work correctly with M10 GPS modules at the moment.

VK3KYY wrote: ↑

Wed May 14, 2025 9:58 pm

Other baud rates are now automatically detected on STM CPU radios, but not on the older GD77 etc radios.

However the RSSI etc screens don't work correctly with M10 GPS modules at the moment.

Thanks Roger,

I will consider M10 in the future. Right now I'm having fun with the GP-02. The next one will have RTC battery backup on it.

Hi,

after retrofitting a gd77 and a dm1701 with gps now i try with my rd-5r. There seems to be enough space between display and board for a bare module, a little ceramic antenna may replace the led external.

Can anyone confirm that reception of serial data on pin 99 from cpu is working in rd-5r?

Actually it is not possible for me to activate gps in menue. The gps-module (atgm336h) is sending nemea with 9600bd.

Is there possible an issue with the special behaviour of cpu pin 97 for switching the led?

Greetings
Christian

It works now.
My fault, i connected pin 99+100 of cpu for easier soldering, after only connecting pin 99 it is ok.
Now the 3d printer has to print a little hat...

CAUTION: Do not use the power of torch led for powering gps module, it is plus of battery!

The switched cpu port from the torch led can not be used direct for switching power of the gps module without desoldering the transister because the basis emitter diode of the transistor limits the voltage to about 0.7 volt.

Christian

Update 05-31-2025
Finally i connected GND of the gps modulde to the collector of the led transistor to be able to switch power of the gps module.
After powercycle it is always needed to switch the gps to on with "SK2 + 5", if it is needed.

Disadvantage
There is no possibility to check if the powerstatus of the gps is on or off.

DC8OH wrote: ↑

Sun May 18, 2025 6:55 pm

It works now.
My fault, i connected pin 99+100 of cpu for easier soldering, after only connecting pin 99 it is ok.
Now the 3d printer has to print a little hat...

CAUTION: Do not use the power of torch led for powering gps module, it is plus of battery!

The switched cpu port from the torch led can not be used direct for switching power of the gps module without desoldering the transister because the basis emitter diode of the transistor limits the voltage to about 0.7 volt.

Christian

Thanks for sharing.

Suggestions needed. I think I have problem with the RTC battery backup. I don't think is does anything. I have two 1701 one with battery and another without. Both of them doing cold boot, about 40 seconds, every time I turned them on. I've tried leave the radio with the backup battery on for 24 hours. Hoping the battery will get charged, but no luck. Am I missing something? any suggestions?

TIA,
Charlie,

KA1CM wrote: ↑

Sat May 24, 2025 11:43 am

Suggestions needed. I think I have problem with the RTC battery backup. I don't think is does anything. I have two 1701 one with battery and another without. Both of them doing cold boot, about 40 seconds, every time I turned them on. I've tried leave the radio with the backup battery on for 24 hours. Hoping the battery will get charged, but no luck. Am I missing something? any suggestions?

TIA,
Charlie,

Not that it helps, but I tried connecting a backup battery to one of the GPS modules which I was testing, and it didn't work either.

Ok, I think I’ve found the problem. The battery I took from GP-02 kit is bad. It looses it charges too quickly. I have replaced it with brand new ML1220 battery and it seems to be good. I will test it a couple day and will report back.

The warm boot only happened for only couple hours after the radio turned off. I don't have the exact preiod yet, but definitely not overnight. Seems like some data has expired in couple hours and after that the radio will have to acquired that data again, hence the warm boot could not happen.