RX issue with fluctuating field strength ?

[DM1DW]

Hi guys,

first I have to thank everybody who is involved in this project. Thank you for this awesome firmware.

I own a GD-77 and an RD-5R and have the same issue with both devices. Charging state does not effect my observations. I tried different beta versions and the stable version, but I still have the same problem:

It appears when I listen to an FM simplex conversation and "person 1" stopp talking and the squelch is closed for a moment. The squelch does not open again or flickers, until I am switching to another channel and then switching back the conversation channel.
When I turn off the squelch while I am hearing the conversation, after 5-30 seconds the sound quality is getting worse. So it make sense, that the squelch would close. After switching to another channel and then switching back, it is ok for 5-30 seconds.

It feels like a channel is being worn out.
On the same antenna, my other radios and SDR works fine, when I hear the same people in simplex.
Funny thing is: It does not happen, when I listen to FM-repeaters. May it is a problem with fluctuating field strength ?
EDIT: Here on video: https://www.youtube.com/shorts/zXnxGUW-nK8

I have no clue, what this could be. Does someone have an idea, or what to test ?

Best wishes and many thanks
Chris DM1DW

[VK3KYY]

Are you using the latest version of the firmware ?

I remember a similar problem a long time ago, but I can't remember the reason, or whether it was a hardware or a firmware problem

[DM1DW]

Yes, I tried the last version and some other versions, including the stable.
Yes, my first thought was the hardware, but my RD-5R has the same issue....

[VK3KYY]

Yes, I tried the last version and some other versions, including the stable.
Yes, my first thought was the hardware, but my RD-5R has the same issue....

OK.

I vaguely remember something similar in the past, but unfortunately I can't remember the cause.
Perhaps someone else can remember

[DM1DW]

Hmm, may an admin can move this thread into the discussions forum to "Bug reports".
May there is someone with an idea.

Thx Chris

[DM1DW]

Hey guys,

I found out some information:

It does not matter if the radio is in channel-mode or VFO-mode. I can hear people on a frequency, after some time, or the person switched (with or without squelsh) the voice quallity gets worse. After switching the channel or frequency and switch back, it works fine.
I only testet beween 144 - 164 Mhz, because I do not have simplex traffic on 70 cm in the near.
It is definitely an problem of changing field strength. May voice processing or something ?

If anyone has an idea, I will be glad.

Best wishes
Chris

[VK3KYY]

Hey guys,

I found out some information:

It does not matter if the radio is in channel-mode or VFO-mode. I can hear people on a frequency, after some time, or the person switched (with or without squelsh) the voice quallity gets worse. After switching the channel or frequency and switch back, it works fine.
I only testet beween 144 - 164 Mhz, because I do not have simplex traffic on 70 cm in the near.
It is definitely an problem of changing field strength. May voice processing or something ?

If anyone has an idea, I will be glad.

Best wishes
Chris

Which radio hardware

We had reports of some radios, like the GD77 having problems with RSSI dropping after a few seconds of changing to the channel.

This doesn't happen on all radios, and we think that the TRx chip used on all the handheld radios, which is the AT1846S , is sometimes partially defective

The AT1846S TRx does not have good out of band signal rejection because its Rx is direct conversion, so these effects may be caused by other signals on different frequencies affecting how the chip works.

The chip literally costs $1 US. see https://www.aliexpress.com/item/1005004533713806.html

So you get what you pay for in terms of quality etc, but thats whats in these cheap radios.


Unfortunately its not possible for the firmware to work around the cheap RF hardware in these radios.

[DM1DW]

It is the same with the GD-77 and the RD-5R. Always the same like in the Youtube Video: https://www.youtube.com/shorts/zXnxGUW-nK8

If the problem would only be on a single radio, I could imagine to change the chip, but are both defective ?
I do not have an air soldering iron, but a jet lighter
When I am the only one with this problem, may it is something else....

I really like the openGD-77 firmware, and I hate to see that my cheap Quansheng works better in scanning simplex channels.
I am thinking about the MD-9600, is the quallity better ?

[VK3KYY]

It is the same with the GD-77 and the RD-5R. Always the same like in the Youtube Video: https://www.youtube.com/shorts/zXnxGUW-nK8

If the problem would only be on a single radio, I could imagine to change the chip, but are both defective ?
I do not have an air soldering iron, but a jet lighter
When I am the only one with this problem, may it is something else....

I really like the openGD-77 firmware, and I hate to see that my cheap Quansheng works better in scanning simplex channels.
I am thinking about the MD-9600, is the quallity better ?

Like I said. All these radios have problems becuase the all use the same RF chip

MD9600 uses different hardware, but its still a cheap chinese radio

If these radios are not high enough quality, you will need to buy a Kenwood, Icom, Yaesu or Anytone etc

[DM1DW]

Hey guys,

before I change the AT1846S Chip. I tried to flash the original firmware from radioddity on my GD-77. It looks like, the problem is gone...
I hate to say it, but 30 minutes ago, with the OpenGD77 firmware, I had the same problems than ever. But with the original Version 6.00.01 it works like charm.
But I miss all the nice features of OpenGD77 right now