OpenGD77

Hi.

I’d like to suggest a few features that I think would be useful:

- On the "Last Heard" page, would it be possible to add an option to save a DMR ID directly as a new contact?

- For the VOX function, could an option be added to play a beep when the device detects a voice and starts transmitting? Currently, it only beeps when transmission ends, according to the PTT release tone setting. As a blind user, I would find it very helpful if there were also a beep at the start of a transmission, so I can tell when VOX has activated.

- At the moment, I can't hear any difference between a call on a talkgroup and a private call. Would it be possible for the device to play a distinct sound or announce via voice prompt when receiving a private call?

- Could SK1 and SK2 (GD77) be used to enable a Morse function? The idea would be to switch the radio into Morse mode, with a menu setting for a Morse keying timer. Holding SK1 would send a series of "Dah" tones, while SK2 would send "Dit" tones.

Apart from that, great project! Thanks to everyone involved.


73s, DO9RE

- Could an automated repeated transmission feature be added? For example, in an emergency, the DMR codec could be used to record a voice message, and a timer with adjustable intervals could be programmed to transmit it automatically. This would allow for an automated distress call without requiring continuous manual operation of the device.

- Now for something a bit crazy. Many people are familiar with the RepeaterBook app, which uses GPS to display nearby repeaters. What if we collaborated with the developers of this app to create a feature that transfers selected repeater information directly to the radio? I imagine this as a tone-encoded transmission: the smartphone generates an audio sequence containing encoded data for frequencies and other parameters. The radio would be set to a listening mode, receive the data from the app, and automatically configure the new repeater.
I know this idea is a bit out there, but I really like it, so I’m putting it out there anyway.

Could it be possible to have independent from display control on keyboard/keys backlight ?

DO9RE wrote: ↑

Wed Feb 26, 2025 9:48 pm

- Could an automated repeated transmission feature be added? For example, in an emergency, the DMR codec could be used to record a voice message, and a timer with adjustable intervals could be programmed to transmit it automatically. This would allow for an automated distress call without requiring continuous manual operation of the device.

As far as I know, the audio signal path to the DMR codec is hardwired from the mic to codec to TX, so it's not possible to send an analog audio recording over DMR.

Maybe it's possible to pre-encode DMR frames and directly TX those but sounds challenging.

DO9RE wrote: ↑

Wed Feb 26, 2025 10:09 pm

- Now for something a bit crazy. Many people are familiar with the RepeaterBook app, which uses GPS to display nearby repeaters. What if we collaborated with the developers of this app to create a feature that transfers selected repeater information directly to the radio? I imagine this as a tone-encoded transmission: the smartphone generates an audio sequence containing encoded data for frequencies and other parameters. The radio would be set to a listening mode, receive the data from the app, and automatically configure the new repeater.
I know this idea is a bit out there, but I really like it, so I’m putting it out there anyway.

This could be done rather easily actually... there's already APRS support in the firmware, and APRS uses Bell 202 modulation which is very easy to implement.

Make a smartphone app, settle on a data format (I'd recommend protobuf for its speed and space efficiency in embedded systems) then make the phone emit a 1200 Hz tone for mark (binary '1') and 2200 Hz tone for space (binary '0') at 1200 baud.

Decode the sound on the radio and do whatever you want with the data, update the contacts, erase flash and rewrite the codeplug, whatever.

First grab the sources and test something out like a "hello world" or rendering a simple dialog box with text on the radio, then take it from there. There's effort involved but this one is actually doable.

Bell 103 and 202 was invented at a time when AT&T didn't allow you to wire a modem to their phone lines so you had to pick up the phone, dial the number and place the handset on the modem (the modems had microphone and speakers on top to place the handset on) so the modulation is easy to implement and very forgiving. I bet you could even find Bell 202 software codecs, or even complete AX.25 implementations written in Swift (iOS) or Java (Android) to build on.