Post
by VK3KYY » Wed Jul 19, 2023 9:42 am
Interesting that the new version of the HD1 uses a USB to Serial converter.
Did anyone take the new radio apart to see what is inside, becuase it sounds very much like the Baofeng DM-1801 / DR-1801, which replaced the MCU + C6000 + AT1846S with a single RF module, and this module is only connected via its Rx and Tx serial data pins, rather than a true USB connection.
Likewise if it is just a DMR module + PA, it may explain why the power output is different, becuase perhaps the DMR module does not supply adequate RF drive to the existing PA.
These modules seem to be contain the C7000 and AT1846S and possibly some Flash memory, so that they are a completely self contained DMR radio
Re: C7000
I've looked at the firmware binaries for the GD-73, which although unencrypted do not seem to have any of the expected data that is normally sent to the AT1846S RF chip, even though the GD-73 has descrete C7000 and AT1846S
In other radio firmwares, which have been decrypted the register numbers of 0x29 and 0x2A are often close together in the code becuase these 2 registers need to be used togeher to set the frequency, but I could not find references to 0x29 and 0x2A near each other in the GD-73 firmware
Of course it could be that the firmware uses 0x29 and (0x29+1) thus making it hard to find where in the binary is setting the frequency.
But if that was the case, then the firmware source code for the AT1846S would not be from the same code base as any other radio we've seen so far, which is a bit surprising, becuase so far, the TYT / Radioddity / Retevis and Baofeng firmware binaries show a high level of similarity, indicating that these firmwares originate from the same company, even though the radio hardware is made by separate companies.
The same applies to the bootloader as well as the firmware.