OpenGD77

Hold down SK2 when powering on.

Unfortunately the companies making and selling all of these radios don't design them or even write the firmware. As far as we know they buy it in from a mystery third party supplier who seems to be very secretive.

Rumor is that it is actually receiving DSBSC not USBSC so doesn't care if it's USB or LSB but obviously will crap out on a CB channel with both. One firmware claims to be able to transmit DSBSC :shock: Yes it is DSB, it is just using the baseband zero IF signal and the LO leakage provides the BFO. ...

I agree, the latest fork of the firmware for the UV-K5 from 'egzumer' is now very good. Someone has done a great job of de-compiling the original firmware (or did they actually manage to get hold of the source from somewhere?) and creating a development environment that allows editing and recompilin...

Further to Rogers comment. The codeplug only supports 1024 channels. The Channel number column in channels.csv allows you to specify exactly where you want to save a channel. That channel number is the one you can enter when in the special 'All Channels' Zone. This allows you to group channels logic...

The RT90/MD9600 has a plug in antenna. It is possible the antenna is unplugged / not fitted / faulty. GPS reception is probably not tested in the factory.

The GPS module and antenna is in the front panel.

Colin G4EML.

As Roger says pins 7 and 8 are grounded in the front panel. You might be able to disconnect those pins from ground and use them for audio but you might need to remove the whole socket to do it as the PCB is double sided. There is low level audio on the volume control which could be used. If you want...

Yes, they do.

If the time is synched from the GPS module then it uses the NMEA sentences sent from the module. NMEA specifies that the time is UTC, so the leap second adjustment from GPS time to UTC should have been done by the module. I don't think that anyone has ever checked this though. If it is really import...

That last document is as good as it gets. The original was an existing scanned diagram for a Yaesu microphone which is almost the same. I just modified it to suit.

Colin.