SDS200 Settings

[Ret_Batt_Chief]

Set my SDS200 display to detail mode. My noise level varies from 170-307 is this normal? My RSSI is showing -81db. Are these normal readings? What exactly do they mean? These are for a digital trunk system.
Analog system I monitor are showing a noise level around 300,000

 

[iMONITOR]

RSSI and noise levels

What's a good RSSI and noise level for VHF P25? I current have -75dBm RSSI.

forums.radioreference.com

 

[Ubbe]

SDS scanners has demodulation noise, the more the signal are modulated the more noise you get. A digital signal are fully modulated so you can probably not get any lower values than the ones you see now. If you listen to just a silent analog carrier you will get 0 as a noise value at about that -80dBm level. As soon as someone starts to speak on an analog channel the noise will go up in a SDS scanner.

If you do not receive any signal at all it will be all noise and the highest value are in the 50,000 range.

You can use the Noise value for analog signals and when you try different filter settings and IFX, to get the lowest possible noise value.
Fot digital signals you will need to configure one field to show D-Error and will show how many errors in the data signal that you have, and try to get it as low as possible using filters and IFX. If that goes higher than 10 then you will have a bad signal with bad audio, or none at all, being decoded.

/Ubbe

 

[palmerjrusa]

SDS scanners has demodulation noise, the more the signal are modulated the more noise you get. A digital signal are fully modulated so you can probably not get any lower values than the ones you see now. If you listen to just a silent analog carrier you will get 0 as a noise value at about that -80dBm level. As soon as someone starts to speak on an analog channel the noise will go up in a SDS scanner.

If you do not receive any signal at all it will be all noise and the highest value are in the 50,000 range.

You can use the Noise value for analog signals and when you try different filter settings and IFX, to get the lowest possible noise value.
Fot digital signals you will need to configure one field to show D-Error and will show how many errors in the data signal that you have, and try to get it as low as possible using filters and IFX. If that goes higher than 10 then you will have a bad signal with bad audio, or none at all, being decoded.

/Ubbe

I've never paid that much attention to the "noise value" on my SDS200/100 scanners.

I have noted that a -100dBm RSSI is about the threshold for "receivability" of a P25 signal.

 

[rrobinso84]

I've never paid that much attention to the "noise value" on my SDS200/100 scanners.

I have noted that a -100dBm RSSI is about the threshold for "receivability" of a P25 signal.

My lowest intelligible digital channels have logged -121dBm. Strongest signals nearby average around -60.

 

[palmerjrusa]

My lowest intelligible digital channels have logged -121dBm. Strongest signals nearby average around -60.

Yep, below -100dBm it starts to get very patchy.

The signal strength of the local P25 Radio System where I'm located is very strong (comes in clear on the SDS100/200s with a decent signal even with no antenna attached) is around -60dBm.