Slight ticking sound

VK3KYY
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Location: Melbourne, Australia

Re: Slight ticking sound

Post by VK3KYY » Mon Dec 21, 2020 9:17 am

do1jml wrote:
Mon Dec 21, 2020 6:29 am
This is when using the radio directly and also happens on FM.

I know that a hand mic can pick up the buzzing sound from the DMR TDMA structure.
Rx or Tx?

do1jml
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Joined: Fri Sep 11, 2020 10:56 am

Re: Slight ticking sound

Post by do1jml » Mon Dec 21, 2020 4:23 pm

TX.

VK3KYY
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Joined: Sat Nov 16, 2019 3:25 am
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Re: Slight ticking sound

Post by VK3KYY » Mon Dec 21, 2020 9:02 pm

Tx FM and DMR ?

do1jml
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Joined: Fri Sep 11, 2020 10:56 am

Re: Slight ticking sound

Post by do1jml » Tue Dec 22, 2020 7:25 am

Yes.

do1jml
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Re: Slight ticking sound

Post by do1jml » Wed Dec 30, 2020 5:22 pm

It seems that this problem is indeed linked with the open firmware. I installed the open firmware on a brand new Baofeng RD-5R and I have the same sound. I looked at the bug reports, the closest that can find is the bug about "motorboarding".

VK3KYY
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Location: Melbourne, Australia

Re: Slight ticking sound

Post by VK3KYY » Wed Dec 30, 2020 7:50 pm

This is a known problem.

Which has been reported many times.

However none of my radios have this problem , and I have all radios supported by the firmware, so I have no way to analyse the cause of the problem

do1jml
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Joined: Fri Sep 11, 2020 10:56 am

Re: Slight ticking sound

Post by do1jml » Thu Dec 31, 2020 6:19 am

I would be happy to lend out a radio if that could help. I am based in Germany.

VK3KYY
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Re: Slight ticking sound

Post by VK3KYY » Thu Dec 31, 2020 6:59 am

do1jml wrote:
Thu Dec 31, 2020 6:19 am
I would be happy to lend out a radio if that could help. I am based in Germany.
Its not practical for me to borrow radios from people, because I could damage them whilst analyzing the problem etc.

I disassemble all my radios and solder wires inside them, and sometimes its not possible to re-assemble them.

ok1pt
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Re: Slight ticking sound

Post by ok1pt » Thu Dec 31, 2020 7:48 am

VK3KYY wrote:
Wed Dec 30, 2020 7:50 pm
This is a known problem.

Which has been reported many times.

However none of my radios have this problem , and I have all radios supported by the firmware, so I have no way to analyse the cause of the problem
hI!
I have 2 GD-77s both are fine, they don't generate any "motorboarding" sound.
However, I have a hypothesis - it might be caused by insufficient filtering of analog circuitry power lines and penetrating the ripple generated by CPU running the program (periodical patterns caused by main loop cycling, periodical interrupts etc) to its power lines. The original software may have different power consumption profile during its run and the generated ripple may have different spectrum (higher frequencies, which are filtered better)...
It's possible that some production batches contain different components, or some of them may be totally missing (to cut the costs)... It's Chinese :-)...

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

Re: Slight ticking sound

Post by VK3KYY » Thu Dec 31, 2020 10:02 am

At least some of the noise is coming in via the audio Analogue to Digital Converter.

There is no noise, even from radio which have "motorboating" if clear the incoming data to 0x00

So the noise is not the result of something else in the firmware, or the way the Tx audio is generated and output.

However, I have no idea why some radios seem to have noise on their audio input, yet the official firmware does not have the noise.

My only guess, is that the engineers know where the noise is coming from and perhaps have something in the official firmware to mask that there is noise.

It could be something as simple as one sample of audio with a spike of noise on it, every 30mS, because by the time the audio has been through the AMBE codec, what comes out the other end, is radically different from what went in.

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