Locked Re: WHAT is CLIPPING - when db = RED #ApacheLabs

Martin G0HDB <marting0hdb@...>

On Thu, Sep 29, 2022 at 06:44 PM, Ron wrote:

My apologies, I directed you incorrectly in my earlier post. Clipping occurs
when you have your receive audio is set too high.

To correct this issue, do the following:

Right click speaker icon in system tray>Sounds>Recording>”Levels” Tab
–Configure so Receive Audio Level is about 30 dB when no signal present.
It's a good idea to test this when connected to a dummy load. Make sure mic
isn't muted (small icon to right of recording level slider bar.

Setting the audio level with the receiver connected to a dummy load won't be a realistic scenario because band noise that's received with an antenna connected will almost inevitably be considerably higher than the thermal noise generated by the dummy load.

I live in what I believe is a fairly typical semi-rural environment albeit with several other houses within a few 10s of metres of my antennas and even on a quiet band such as 10m when I disconnect the antenna from my receiver and connect a dummy load instead the noise level as displayed on the WSJT-X 'thermometer' drops by around 20dB. This indicates that the received ambient noise in my environment is approx 20dB higher than the thermal noise generated in a dummy load.

Anyone who finds that disconnecting their antenna from the receiver results in little or no change in the reading on the WSJT-X 'thermometer' when receiving only band noise is indeed very fortunate - their ambient noise level must be extremely low!

Martin G0HDB

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