OpenGD77

I think that probably rules out the display as a way of saving power.

Roger,

Don’t forget the display on OpenGD77 is permanently selected with chip select held low all the time. I don’t know if that increases the power consumption but it might. It is pretty easy to modify the code to only set chip select low when sending data to the display.

Colin.

Many commercial systems use text messaging and data in addition to voice. If the system is used by multiple companies some of the voice traffic might be encrypted. OpenGD77 only decodes un-encrypted voice calls.

As far as I am aware the only documents we have are in the docs folder on GitHub. As with many of the Chinese chips there is not a lot of detail.

Roger,

I also have not heard the problem on my radios so it’s difficult to diagnose.

One possible cause could be the screen update. The microphone signal shares the same ribbon cable as the screen and keyboard.
Have you tried a version which doesn’t write to the screen during Tx?

Colin.

Hi Roger,

I may have a fix for this, I will send you and email.

Colin.

This is probably due to the same bug you previously reported about the audio amp remaining enabled when changing to an unused timeslot.

The scan hold is controlled by the state of the audio amp. If the audio amp remains enabled then the scanning software will see that as an active channel.

Transmitting both timeslots using a GD77 is theoretically possible but it is not as simple as just supplying it with a full frame of data. To implement the hotspot mode Roger has been very clever and is actually taking the encoded data from the host and decoding it back to the source data which is t...

Just a thought.... are we muting the microphone input while generating DTMF Tones?
If not then that might explain why the volume control has an unexpected effect.