Choppy receive audio

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NC3Z
Posts: 2
Joined: Wed Sep 30, 2020 12:23 am

Choppy receive audio

Post by NC3Z » Thu Nov 03, 2022 8:30 pm

I am using 2 GD77 and 1 MD9600 with the latest Open firmware as of 2 Nov. All 3 radios exhibit the same issue. If a transmission is originated on another linked MMDVM repeater to another MMDVM repeater the GD77 and MD9600 received signal has a fast chop to the decoded audio.

We have proven that the stock firmware in a GD77 or MD9600 does not exhibit this issue. And other non-openCPS firmware radios have no issue. It is only on radios flashed with OpenCPS firmware.

Here is an example https://youtu.be/Rz7J88Es620 of the choppy audio.


youtu.be/Rz7J88Es620

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Choppy receive audio

Post by VK3KYY » Thu Nov 03, 2022 9:26 pm

Your video does not show side by side comparisons with one radio runing the official firmware and one running the opengd77, so its impossible to see a direct comparison of both firmwares in operation at the same time.

I also don't understand your description of the network setup, or what network you are using.

Do you mean that the transmitting station is transmitting into a full MMDVM duplex repeater using something like a board from Repeater Builder and that is the same configuation as the repeater that you are listening to.

Do you mean that if either repeater is not MMDVM then the problem doesn't occur?

Does this apply to MMDVM Hotspots , simplex or duplex mmdvm hotspots?

What was the BER on both repeaters at the time of the transmission.

Have you confirmed the frequency calibration of the radios when running the official firmware and the OpenGD77 firmware?


i.e there are hundreds of factors which can effect the ability of the radios to decode the audio.

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