Hum (interference) in DM-1701
Hum (interference) in DM-1701
Recently I noticed a problem with the DM-1701 radio, because when I mute the radio completely and it receives the correspondent's signal, there is a humming noise in the background. Of course, you can hear it by putting your ear to the speaker or listening with headphones. Naturally, as the volume increases, the real signal drowns out the interfering one and the problem is no longer bothersome. Does anyone have such a case? The loaded software is OpenGD77. I don't have the original software and I can't check it.
Re: Hum (interference) in DM-1701
The GD77 has a similar problem when the battery is charged to above 8.4V
Re: Hum (interference) in DM-1701
It could also be the backlight dimming. Does it still make a sound if the backlight is set to 100%?
Colin G4EML
Colin G4EML
Re: Hum (interference) in DM-1701
Its worth checking the backlight, but from what I can remember , on the handlhelds, we use a PWM frequency well above what people can hear.
Its only the MD9600 which has analogue filtering of the display backlight where we had to use lower frequencies
Its only the MD9600 which has analogue filtering of the display backlight where we had to use lower frequencies
Re: Hum (interference) in DM-1701
Charging the battery has no effect on these sound effects, but when the backlight is at 100%, this unwanted sound is almost inaudible. Only when you reduce the backlight does this effect become more audible. So the reason is the display operation.
Re: Hum (interference) in DM-1701
I have this issue when backlight is less than 100%. A "buzz" sound is produced when tx and rx. I have not tested the impact on DMR, only on analog.SO5AJG wrote: ↑Thu Oct 05, 2023 10:07 amRecently I noticed a problem with the DM-1701 radio, because when I mute the radio completely and it receives the correspondent's signal, there is a humming noise in the background. Of course, you can hear it by putting your ear to the speaker or listening with headphones. Naturally, as the volume increases, the real signal drowns out the interfering one and the problem is no longer bothersome. Does anyone have such a case? The loaded software is OpenGD77. I don't have the original software and I can't check it.
did you find any solution?
Re: Hum (interference) in DM-1701
Generally, I leave this topic because I don't put my ear to the speaker. Usually, with useful sounds and a certain volume set, this is not noticed. I simply pointed out that such a thing exists, but I can live with it.