Pre-release 9th April

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SQ7PTE
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Re: Pre-release 9th April

Post by SQ7PTE » Fri Apr 10, 2020 6:21 am

Roger.
This happens at frequencies with CTCSS added
That is why I have already asked on the forum whether the DCS function is active (working) because I care more about it.
greetings

VK3KYY
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Re: Pre-release 9th April

Post by VK3KYY » Fri Apr 10, 2020 6:33 am

SQ7PTE wrote:
Fri Apr 10, 2020 6:21 am
Roger.
This happens at frequencies with CTCSS added
That is why I have already asked on the forum whether the DCS function is active (working) because I care more about it.
greetings
Can you try this version.
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SQ7PTE
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Re: Pre-release 9th April

Post by SQ7PTE » Fri Apr 10, 2020 6:42 am

I have uploaded.
I am waiting patiently for any symptoms, nothing bad is going on right now.
You need some time for testing.
I wonder what will happen to colleague Rob, who also reported this error.

VK3KYY
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Re: Pre-release 9th April

Post by VK3KYY » Fri Apr 10, 2020 6:51 am

OK

oh4va
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Re: Pre-release 9th April

Post by oh4va » Fri Apr 10, 2020 6:52 am

VK3KYY wrote:
Fri Apr 10, 2020 6:17 am
Do you mean if a channel has CTCSS ?
This happens on my radio too while listening a channel CTCSS SQ enabled. I have an SvxLink simplex node here at home which is transmitting on the freq 433.575 MHz CTCSS 127.3 Hz.

73 de Veijo

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Re: Pre-release 9th April

Post by oh4va » Fri Apr 10, 2020 7:07 am

VK3KYY wrote:
Fri Apr 10, 2020 6:33 am
Can you try this version.
I have been running this version a few minutes now. It works well, the receiver has been quiet when there is no activity on the channel.

73 de Veijo

Edit: Corrected a typo and removed one word.
Last edited by oh4va on Fri Apr 10, 2020 7:53 am, edited 1 time in total.

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Re: Pre-release 9th April

Post by VK3KYY » Fri Apr 10, 2020 7:38 am

oh4va wrote:
Fri Apr 10, 2020 7:07 am
VK3KYY wrote:
Fri Apr 10, 2020 6:33 am
Can you try this version.
I have been running this version a few minutes now. It works well, the receiver has now been quiet when there is now activity on the channel.

73 de Veijo
OK.

Its a bug in Colin's (G4ELM)'s bug fix.

I'll need to check what bug Colin's change has fixed, because we need a fix that does not have side effects ;-)

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Re: Pre-release 9th April

Post by VK3KYY » Fri Apr 10, 2020 8:22 am

I found the thread that Colin's change has fixed

viewtopic.php?f=11&t=794

I'll try to find an alternative fix for this bug

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Re: Pre-release 9th April

Post by oh4va » Fri Apr 10, 2020 8:28 am

VK3KYY wrote:
Fri Apr 10, 2020 8:22 am
I'll try to find an alternative fix for this bug
Roger, that's great.

BTW: Any idea what may cause whirr in the receive audio while listening a FM channel? It is not a local interference. Two more GD77 radios are on the way. When they arrive here in Mikkeli I have a chance compare these radios.

Regards Veijo

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Re: Pre-release 9th April

Post by VK3KYY » Fri Apr 10, 2020 10:42 am

oh4va wrote:
Fri Apr 10, 2020 8:28 am
VK3KYY wrote:
Fri Apr 10, 2020 8:22 am
I'll try to find an alternative fix for this bug
Roger, that's great.

BTW: Any idea what may cause whirr in the receive audio while listening a FM channel? It is not a local interference. Two more GD77 radios are on the way. When they arrive here in Mikkeli I have a chance compare these radios.

Regards Veijo
The bug appears to be that if CTCSS is assigned to a channel and the Rx detects a tone, it will always turn on the audio amp, even if the signal strength is below the squelch threshold.

In trx.c

Code: Select all

void trxCheckAnalogSquelch(void)
See line 404 in trx.c

Code: Select all

		if(((!rxCTCSSactive) && (trxRxNoise < squelch)) || ((rxCTCSSactive) && (trxCheckCTCSSFlag())))
		{
			GPIO_PinWrite(GPIO_RX_audio_mux, Pin_RX_audio_mux, 1);// Set the audio path to AT1846 -> audio amp.
			enableAudioAmp(AUDIO_AMP_MODE_RF);
		}


trxCheckCTCSSFlag() reads address 0x1C from the AT1846, and in the programming manual data sheet (See the docs/data_sheets ), bit 8 is ctcss2 compared result

I think what is possibly happening is that the AT1846 is miss interpreting noise as a CTCSS tone and hence enabling the audio amp, and also setting the audio path mux to connect the AT1846S to the amplifier

The output audio from the AT1846S is not muted by the AT1846, so this will result in either hiss or probably a small amount of QRM signal, being output to the speaker

Looking at the original bug. I'm not sure it really is a bug.

Colin's description of the problem is
The problem is that if you remove the tone whilst still transmitting the squelch does not close. Not something that is easily done on most radios but a custom repeater like that described might continue to radiate carrier and just turn off the tone.

It can be demonstrated by receiving a signal with CTCSS and reducing the squelch level to minimum whilst receiving. When the signal is removed the squelch remains open.

(Probably a linked bug is if you open the squelch on a CTCSS channel so the green light is on a signal containing CTCSS will not be received)

I don't know of any systems which remove the tone in the middle of the transmission. I can't easily replicate this without writing some special code in the OpenGD77 to turn of the tone in the middle of the transmission.


I think perhaps if you open the squelch that even if there is a CTCSS applied to the channel (or VFO) that you should hear hiss or a signal (whatever is on that frequency)

I find it strange that I can open the squelch and the green LED comes on, but because I have CTCSS set on a channel that I don't hear anything.

Anyway, I'll take another look at the code...

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