OpenGD77 is an open source (GNU General Public Licence Version 2)
and is a great effort on the part of Rodger Clark, VK3KYY, in Melbourne and his
co-authors. Rodger Clark is a Freelance IT Consultant & Developer, based in Melbourne Australia and
is a legend in DMR firmware, modifications, and the DMR mode. It is the opinion of man
that this firmware is far superior to the manufactures. I am certaintly, of that
opinion. He is to be congratulated.
Rodger's web site is here:
https://www.rogerclark.net/
The User Forum is here:
http://www.opengd77.com/index.php
It is the opinion of many that this firmware is far superior to the manufactures
firmware.
The github repository is here:
https://github.com/open-ham/OpenGD77
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Note the Callsign is blank and the DMR ID is a nonsence as the OpenGD77
CPS will not allow it to be blank.
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The Codeplug comes with marine VHF and CB UHF frequencies.
As we know, the marine and citizen band channels are outside the amateur radio bands
As a resukt they are enabled to receive only. If you try to tramsmit on these frequencies
you will get an error message:
ERROR - Out of Band
To enable out of band transmitting do the following:
Note The use of the VHF Marine Bands requires operators to hold a minimium of a
SHORT RANGE OPERATOR CERTIFICATE OF PROFICIENCY (SROCP)
Australian Maratine College's SROCP:
https://www.amc.edu.au/industry/omc/certificates/short-range-operator-certificate-of-proficiency-srocp
Note thes are software controlled band limits, and this is a separate issue to
the hardware band constraints. The RF hardware can't technically operate reliably
outside these bands.
Note that, the OpenGD77 community and documentation often refer to the SK and TK keys, other times to
the Black, Blue, Orange, and Green and Red keys. This table may help decipher the instructions.
| Button | Position | Colour | Short press | Long press |
|---|---|---|---|---|
| SK1 | 1st one under the PTT | Black | Menu | Nothing programmed yet |
| SK2 | 2nd one under the PTT | Blue | Channel info | Channel info |
| TK | Top button next to antenna | Orange | High/low power select | Long press = Scan On/off |
| Menu | Left-hand button under the screen | Green | Menu | |
| Exit | Right-hand button under the screen | Red | Exit or Back |
On Windows download FirmwareLoader.exe.
On Linux download the firmware loader, firmwareloader_linux.zip, that runs on the Ubuntu.
Be sure to extract and update the udev rules.
On both platforms, the firmware file, OpenGD77.sgl, is required.
I downloaded the User Guide, OpenGD77_User_Guide.pdf, but found it failed to navigate or link correctly, so
I then downloaded the Source file, Source code(zip) that linked to OpenGD77-R2020.06.27.zip and extracted
the User Guide, OpenGD77_User_Guide.html and the OpenGD77 Quick Guide Graphic.jpg.
Be sure to check the github repository for more current versions. This is current as at August 2020.
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CPS Update Mode:
To read and write the code plug (configuration) data turn your radio off,
then connect it to your PC via the cable, and then turn the radio on. No button
are required to be held down.
Firmware Update Mode:
To allow the firmware to be updated, turn your radio off, then connect it to
your PC via the cable, then hold down the
two buttons, black and blue ones, below the PTT button on the left hand side,
and then turn the radio on.
The radio screen will be black with the green light on only, which means the
radio is in firmware upgrade mode.
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The programming cable contains no electronics and is simply a wired connection, so
it is possible to manufacture one in the shack.
The radio contains the communication hardware and is a FREESCALE SEMICONDUCTOR INC. USB COMPOSITE DEVICE.
The hardware descriptor is: idVendor=15a2, idProduct=0073, bcdDevice= 0.02.
This is a USB HID, human interface device class and a USB Composite Device.
A Composite Device as the name suggests, is a peripheral device that supports more
than one device class in the one physical USB port.
See:
https://www.keil.com/pack/doc/mw/USB/html/dev_comp_tutorial.html for more details.
It is loaded as a Abstract Control Model (ACM) USB Devices or often called a "Virtual Comm Port".
See:
https://www.keil.com/pack/doc/mw/USB/html/group__usbh__cdcacm_functions.html for more details.
Source:
http://members.optuszoo.com.au/jason.reilly1/GD77mods.htm
The linux system log before the Open Firmware load:
The Linux system log before the Open Firmware load performed on Windows 10::
I do not understand why this changed after I loaded the OpenGD77 firmware. Maybe the
firmware updates the devices firmware in the phone. Maybe this is the resolved by
loading the udev rules.
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The OpenGD77 Code Plug Software will not run under Linux at present, although a
Linux version is foreshadowed. So it is time to move to the Windoze platform.
I am running Windows 10. Download the OpenGD77 application here:
https://github.com/rogerclarkmelbourne/OpenGD77CPS/releases
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I started with this code plug from VK3TBS: https://github.com/vk3tbs/Ben
Even though it was written in 2019 it was the best
I could find and a good starting point for VK4-land. I then exported the code plug
to csv files with the GB3GF utility. I then loaded these into open Office where I could
edit these with all the power of a spreadsheet. However, I consistantly got errors when
attempting to reload these into the CPS application.
So, make sure that all programs are closed that are accessing the csv files or the
load will crash. No harm but you will have to start again.
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TX Inhibit Quick Key Override:
Allows transmission to be sent on a busy channel. The user accomplishes this by
double pressing the PTT within one second.
Read this resource to understand some of the GD77's terms and configurations
Documentation Help for Radioddity GD-77 / CPS 2.0.5
https://documentation.help/Radioddity-GD-77-CPS-2.0.5/
Note that only analog mode supports this feature.
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