TYT MD-9600 / Retevis RT-90 : Experimental version

[AA3RP]

To AA3RP,

Thanks for the offer of a radio for testing. Between the three main developers we already have examples of each of the 3 major radio versions. So at the moment we do not really need another.

Hang on to it, there is a chance it may work with the new firmware when it is released.

Colin G4EML.

Colin G4EML,

Will keep my hands on it. I am looking forward to the OpenGD77 firmware transition to the MD-9600. I have GD77s / DM-1801s / RD-5r and it makes those radios so much more than what they are with factory firmware.

The best way to communicate with me would be email as I do not check here daily.

Finally do you have a part number for that A pot to replace the factory B pot for the volume control?

Robert AA3RP

[I1KDO]

Hello
does anyone know if on the pins 7-8 of the microphone which are not used, if it is USB wired?
it would be convenient for in-car use.
Thank you
73 I1kdo
Lorenzo

[G4EML]

Robert AA3RP.....

The closest Log pot that I have been able to find is made by ALPS part number RK09L1140A5E .
This is stocked in the UK by R.S Components and is also stocked by Mouser.
It is listed as being discontinued on the Mouser site but they still have stock available at the moment.

It fits the PCB layout perfectly, but the mounting thread is larger than the original so the front panel hole needs enlarging slightly and the mounting nut cannot be fitted. However it is not really needed and the knob fits perfectly, leaving the radio looking just like the original.

Colin.

[G4EML]

Lorenzo,

Pins 7 and 8 of the microphone socket are connected to ground in the front panel. It might be possible to modify a radio and connect those two pins to the USB connections with a short twisted pair cable. I don't think anyone has ever tried to do it.

Colin.

[I1KDO]

Thanks Colin
now I am trying to make a kit for the car free hands and I have already connected the 8 pins in transit to the remote RJ45 socket so if it becomes feasible the USB will be even more useful also for updates
when it is finished I will send you photos and wiring diagrams.
Question: Did anyone notice a whiff of background in the transmission? I don't know if it did it with original FW but many who use it and listen to them don't think so ....
could it be caused by FW Open?
let's hear if others have this problem
73
Lorenzo

[G4EML]

I am not sure what you are referring to regards the background?

There is a very slight whine if you have the backlight set to less than 100% and this may be worse on some radios than others. it is due to interference between the backlight and the microphone supply. There is not much we can do about that, it is a hardware problem. The original firmware didn't allow backlight dimming.

Colin.

[I1KDO]

OK that's the problem 100% it doesn't but not even Zero ....
it could be an idea to turn off the display when it goes on transmission, it is very annoying, I will try to try to filter better or shield something !!!!
Thanks for the info
Lorenzo

[DJ0HF]

With the backlight dimmed I hear it too but only on FM not on DMR with my RT-90. I think it might indeed be a good idea to turn off the display on transmit when the brightness has been set to less than 100%.
Ian

[VK3KYY]

With the backlight dimmed I hear it too but only on FM not on DMR with my RT-90. I think it might indeed be a good idea to turn off the display on transmit when the brightness has been set to less than 100%.
Ian

It would need to be an option because no backlight during Tx means you can't see the display e.g. countodown timer etc

Also my radios do not have a noticable noise on Tx even on FM

[ON6XX]

Here also a slight noise tone audible in FM. (not disturbing to me). Another option could be to switch the brightness to maximum at tx