Retevis RT9000D DSP audio/noise blanker?

[express315]

I did my best to steer clear of chinese radios due to ridiculous menu structures, poor reliability and multitude of glitches.
Lately I became interested in 222 mhz ham band but could not afford spending money on latest Alinco.
I bought RT9000D 220-260 mhz from Retevis HK website. I have also looked at TYT TH9000D, which seems to be exactly the same thing.
In the end Retevis won because I could download manual, driver and software from the sellers website.

RT9000D tested well during couple of 222 mhz FM nets, both via simplex and via repeater.
However I had noticed right away that radio sounded very differently from my many other analog FM radios.
First of all there was no noise even with the squelch down. Second - the audio was very flat and featureless, as if coming out of a digital radio.
The latter is exactly why I refuse to do digital and prefer analog voice for all my ham activities.
Other than radio display going blank regularly and needing a power down to reset (at least some glitch was naturally anticipated!) the radio works fine.
After programming the RT9000D front buttons the same way I do for my Vertex radios (using Retevis cable and software) the radio has become usable.
Whatever functions were assigned there from factory no sane person can ever navigate without getting completely lost.
Finally today I got time for bench testing and hooked up the radio to a service monitor. I can confirm it does 15, 30 and 60 watts output.
RX sensitivity is normal and the squelch behaves the usual- opens at slightly higher signal level compare to when it closes.
However again there is a noise blanker that still attenuates the audio till about 10dbm more signal strength after squelch opened.
When tested Tx, Rx with another radio the audio coming out of RT9000D sounds very "digital" and there is a pronounced echo (delay),
just like when playing with two digital radios one next to another. I am very much convinced that there is a DSP audio processor/noise blanker installed
in the audio path of RT9000D. I very much would like to get rid of it if I am able to figure out how to.

My question for any of you who have had experience with TH9000D or RT9000D if you have had similar processed audio or a normal analog audio?

 

[knockoffham]

I did my best to steer clear of chinese radios due to ridiculous menu structures, poor reliability and multitude of glitches.
Lately I became interested in 222 mhz ham band but could not afford spending money on latest Alinco.
I bought RT9000D 220-260 mhz from Retevis HK website. I have also looked at TYT TH9000D, which seems to be exactly the same thing.
In the end Retevis won because I could download manual, driver and software from the sellers website.

RT9000D tested well during couple of 222 mhz FM nets, both via simplex and via repeater.
However I had noticed right away that radio sounded very differently from my many other analog FM radios.
First of all there was no noise even with the squelch down. Second - the audio was very flat and featureless, as if coming out of a digital radio.
The latter is exactly why I refuse to do digital and prefer analog voice for all my ham activities.
Other than radio display going blank regularly and needing a power down to reset (at least some glitch was naturally anticipated!) the radio works fine.
After programming the RT9000D front buttons the same way I do for my Vertex radios (using Retevis cable and software) the radio has become usable.
Whatever functions were assigned there from factory no sane person can ever navigate without getting completely lost.
Finally today I got time for bench testing and hooked up the radio to a service monitor. I can confirm it does 15, 30 and 60 watts output.
RX sensitivity is normal and the squelch behaves the usual- opens at slightly higher signal level compare to when it closes.
However again there is a noise blanker that still attenuates the audio till about 10dbm more signal strength after squelch opened.
When tested Tx, Rx with another radio the audio coming out of RT9000D sounds very "digital" and there is a pronounced echo (delay),
just like when playing with two digital radios one next to another. I am very much convinced that there is a DSP audio processor/noise blanker installed
in the audio path of RT9000D. I very much would like to get rid of it if I am able to figure out how to.

My question for any of you who have had experience with TH9000D or RT9000D if you have had similar processed audio or a normal analog audio?

I am just guessing, but in the last few years I have owned a multitude of horribly documented cheap Chinese radios. If it has a proprietary CPS, there is probably an improperly named setting somewhere in a menu that disables the audio processor. A lot of the proprietary Chinese radios have all their menu functions also able to be changed via programming software. Another probably lame suggestion is maybe there is something in the user manual?

 

[express315]

Thank you for the response. I have certainly looked through the manual settings menu and found nothing of the like.
I will look again in the stock cps software for the switch, in case I missed it.
On the other note I have made a mistake I think by getting the latest PLUS version.
I suspect the previous "standard" version may not have had this audio processor/ noise blanker.
Manufacturer's website mentions nothing of it but some retailers call it "AI noise cancelling".
I call it garbage. Last night I took part in a chat over repeater and I was disgusted how much distortion and extra noises it creates.
When incoming signal audio level is low and the processor threshold is not triggered and I can hear clear undistorted and unprocessed audio though attenuated by this noise blanker. It acts as if there is a second squelch just in the audio path. Once audio signal level threshold is crossed a loud crack is heard and now the audio comes through without attenuation but now all digitally garbled. Very similar if not identical of how digital radios sound at insufficient RF signal levels.
I looked inside and compared what I saw with pictures posted on internet. I did not find any hardware differences except for those related to a different RF band. These radios are not chip - about $150 usd on average and there are lots of them in use. There must be people around with access to schematics and better overall knowledge of this radio. I have not found yet any group, chat or forum dedicated to this radio model.

 

[knockoffham]

Thank you for the response. I have certainly looked through the manual settings menu and found nothing of the like.
I will look again in the stock cps software for the switch, in case I missed it.
On the other note I have made a mistake I think by getting the latest PLUS version.
I suspect the previous "standard" version may not have had this audio processor/ noise blanker.
Manufacturer's website mentions nothing of it but some retailers call it "AI noise cancelling".
I call it garbage. Last night I took part in a chat over repeater and I was disgusted how much distortion and extra noises it creates.
When incoming signal audio level is low and the processor threshold is not triggered and I can hear clear undistorted and unprocessed audio though attenuated by this noise blanker. It acts as if there is a second squelch just in the audio path. Once audio signal level threshold is crossed a loud crack is heard and now the audio comes through without attenuation but now all digitally garbled. Very similar if not identical of how digital radios sound at insufficient RF signal levels.
I looked inside and compared what I saw with pictures posted on internet. I did not find any hardware differences except for those related to a different RF band. These radios are not chip - about $150 usd on average and there are lots of them in use. There must be people around with access to schematics and better overall knowledge of this radio. I have not found yet any group, chat or forum dedicated to this radio model.

Wow. That is strange. Well, hopefully it is a rebrand of another model and eventually you can find information out there. It sounds like the "plus" might have something to do with it. Maybe it would be worth checking AliBaba or AliExpress for similar models. Perhaps contact Retevis directly, I've had some of these companies be helpful in the past. Just for laughs here is a CPS screenshot of my newest cheap Chinese radio