Unsquelched audio after receiving analog signal

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EA5JAQ
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Unsquelched audio after receiving analog signal

Post by EA5JAQ » Fri May 19, 2023 9:20 am

Hi all,

I just noticed in my MD-UV390 that after receiving a signal or using monitor mode in an analog chanel, the next beep (for example, when entering a menu, etc) sounds with some unsquelched audio (like a "click" sound).

Here's how to replicate the issue:
1. Use monitor mode in an analog channel, or receive an analog signal
2. Press green to enter the main menu. The beep will have a loud "click" sound. All the following beeps will sound fine.

This doesn't happen in a digital channel or in the DM-1801 (only other supported radio I could test). Only in analog channels in the MD-UV380/390.

I tried investigating the issue in the source code but so far had no luck (and also I've been quite busy lately), but I'll keep trying to solve it.

Hope this helps,
73

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DL1GG
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Re: Unsquelched audio after receiving analog signal

Post by DL1GG » Fri May 19, 2023 10:04 am

EA5JAQ wrote:
Fri May 19, 2023 9:20 am
I just noticed in my MD-UV390 that after receiving a signal or using monitor mode in an analog chanel, the next beep (for example, when entering a menu, etc) sounds with some unsquelched audio (like a "click" sound).
I cannot reproduce the observation with my Retevis RT3S. First beep after FM sounds fine.
EA5JAQ wrote:
Fri May 19, 2023 9:20 am
1. Use monitor mode in an analog channel, or receive an analog signal
If I leave monitoring mode, there's a short audio blank, then a slight crackle sound, as if the squelch needs some more time to re-engage. Maybe that is FM audio for very short time. So there's no continuous audio blank between leaving monitor mode and having squelched FM. But that unwanted audible period is way too short to be annoyed about IMHO.
EA5JAQ wrote:
Fri May 19, 2023 9:20 am
This doesn't happen in a digital channel or in the DM-1801 (only other supported radio I could test). Only in analog channels in the MD-UV380/390.
Talking about the monitor mode, it behaves quite funny on a RT3S: If you push and hold the lower side button on a FM channel, the mode changes to DMR for a second, then switches back to FM followed by engaging the monitoring mode. Is that by design?

Another interesting thing is, that a keypad beep interrupts FM audio completely, but that might be by design, so we have that beep noticeable against the very present FM noisefloor.

SA0BUX
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Re: Unsquelched audio after receiving analog signal

Post by SA0BUX » Fri May 19, 2023 10:17 am

DL1GG wrote:
Fri May 19, 2023 10:04 am


Talking about the monitor mode, it behaves quite funny on a RT3S: If you push and hold the lower side button on a FM channel, the mode changes to DMR for a second, then switches back to FM followed by engaging the monitoring mode. Is that by design?
Manual doesn't say anything about it but maybe they use the same function regardless on if it's a DMR or FM channel.
(Haven't tested what will happen if I press monitor on a channel with active DMR)
When Monitor mode is active:

In FM mode: any Rx CTCSS / DCS filter is disabled, and the squelch is changed to be fully open.
In DMR mode: the TG, TS and CC filters are disabled, and if no DMR signal is detected within 250mS the radio is switched to FM mode with the CTCSS / DCS and squelch disabled.

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DL1GG
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Re: Unsquelched audio after receiving analog signal

Post by DL1GG » Fri May 19, 2023 11:17 am

SA0BUX wrote:
Fri May 19, 2023 10:17 am
Manual doesn't say anything about it but maybe they use the same function regardless on if it's a DMR or FM channel.
(Haven't tested what will happen if I press monitor on a channel with active DMR)
When Monitor mode is active:

In FM mode: any Rx CTCSS / DCS filter is disabled, and the squelch is changed to be fully open.
In DMR mode: the TG, TS and CC filters are disabled, and if no DMR signal is detected within 250mS the radio is switched to FM mode with the CTCSS / DCS and squelch disabled.
Yeah, you might be right. It feels like to be the second procedure described is the default way, regardless the mode one comes from.
As of my observation, 250ms seems to be the exact time period of that unexpected mode change indeed.

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