OpenGD77

a bit confused. i live in a rural area so I am only able to use a dmr radio with a hotspot. does the latest firmware allow me to purchase a raspberry pi and NOT a mmvdn hi hat to use the gd77 through its own hihat with pi-star? Thanks.

it will allow you to turn the gd77 into a hotspot, but you will need another dmr radio for receive and transmit

great tutorial, pistar now lists open gd77 hotspot in its dropdown menu of modems
its the very last one at the bottom of the list
i tried to upload a screenshot but was informed that 195kb was too big (gasp) lol

Its an old video, so some stuff is out of date now...

The OpenGD77 firmware incorporates code that turns a GD77 into the radio portion of a simplex hotspot, attached to a Raspberry Pi computer (like the pictured ZeroW) via the USB connection - same cable used for programming the radio and updating it's firmware.

Since it's a radio implemented with actual transmitter and receive hardware (with Automatic Frequency Control) it can perform considerably better than the typical Software defined Radio based HotSpot hat card. This includes lower bit error rate impact on receive, and up to 5 watts of transmit power (note that they GD77 is not rated by the manufacturer for continuous transmit at this power...). Be sure to use an external antenna - not the radio mounted stubby... Otherwise, this will interfere with the USB cable, which is not well shielded.

When PiStar initializes on the Raspberry Pi computer, and it is configured for USB attachment to a GD-77 running OpenGD77 firmware, the radio will detect the mode change, and switch to hotspot mode.

Note that you can also "Cast" display information to the radio from PiStar (showing the PiStar computer's IP address on the GD77 screen.