SDS100/SDS200: sds200 P25 distorted audio

[Ubbe]

Decode Error 0 – 80

Receive Signal Strength Indicator -100 dBm

Continuing to experiment with filters. Does D-ERROR have units ?

-100dBm are pretty low but should work okay. D-error are showing the number of errors in the data it decodes. When it goes up to 5 it starts to be an issue and 10 gives distorted audio and higher numbers starts to mute the audio and totally stop decoding.

The filter are 10MHz wide and you only have set a 1MHz wide spectrum when you checked for strong signals. SDS scanners receivers are not working like a "normal" scanners and any signal within 10MHz range can affect reception, that's why Uniden added the filter settings to just the SDS scanners. The Off setting are actually the normal setting that are used in Unidens other scanners. The Normal and Invert and their Wide settings are low pass and high pass filters that will attenuate strong signals above or below the monitored frequency.

The IFX setting are done to each unique frequency and will change where interference will appear in the frequency band.

/Ubbe

 

[Nasby]

-100dBm are pretty low but should work okay. D-error are showing the number of errors in the data it decodes. When it goes up to 5 it starts to be an issue and 10 gives distorted audio and higher numbers starts to mute the audio and totally stop decoding.

The filter are 10MHz wide and you only have set a 1MHz wide spectrum when you checked for strong signals. SDS scanners receivers are not working like a "normal" scanners and any signal within 10MHz range can affect reception, that's why Uniden added the filter settings to just the SDS scanners. The Off setting are actually the normal setting that are used in Unidens other scanners. The Normal and Invert and their Wide settings are low pass and high pass filters that will attenuate strong signals above or below the monitored frequency.

The IFX setting are done to each unique frequency and will change where interference will appear in the frequency band.

/Ubbe

IFX can only be done on individual frequencies and not on a trunking system correct?

 

[hazrat8990]

IFX can only be done on individual frequencies and not on a trunking system correct?

It does work on trunking, you just have to apply it to the problem frequencies carrying voice traffic on the site.

 

[werinshades]

IFX can only be done on individual frequencies and not on a trunking system correct?

In Sentinel, Edit...Edit Profile...Miscellaneous Tab...lower right column...Intermediate Frequency Exchange...add frequency or frequencies, Write to Scanner. That applies IFX on trunking frequencies.

 

[Ubbe]

In Sentinel, Edit...Edit Profile...Miscellaneous Tab...lower right column...Intermediate Frequency Exchange...add frequency or frequencies, Write to Scanner. That applies IFX on trunking frequencies.

I would suggest to have the display show the voice frequency and if one seems to work worse than the others then enter only that frequency to be monitored, Channel+freq+Channel and then you can quickly do Fn+7 to toggle IFX on and off while listening and looking at D-errors.

Then you can also go into the menu down to "Srch/CloCall Opt" and to "Set Filter" and change the filter settings just for that manually entered frequency, and then push the Avoid button to go back to that manually entered frequency and listen if you get any improvement. If any settings improve reception then add that to the site. Check if any other voice channel got worse from that filter settings. It might take several tries to select a filter that works best for all frequencies in the same site.

IFX might change which filter that works best, so if it's difficult to find an appropriate filter then toggle IFX and try again. Settings are location dependent, where in the frequency band you have your other local transmitters, so one persons settings for a system may not be the best one to use to another person.

/Ubbe

 

[n1moy]

In my case the ‘Invert’ filter appears to be the most effective at improving intelligibility. Decode Error in the range of 0 – 40.

Use of Intermediate Frequency Exchange [IFX] did not noticeably diminish D-ERROR.

One observation is that subdued audio transmissions are less likely to result in high Decode Errors. The outcome of louder audio is an increase in errors.

Pursuing further improvement.

 

[Ubbe]

Decode Error in the range of 0 – 40.

If it fluctuates, it stays at a low value below 5 and suddenly goes up in the 40's during a conversation on the same frequency, then that indicate that there's a local transmission that interfere with reception. If it's too close in frequency then filter and IFX setting will not help.

One observation is that subdued audio transmissions are less likely to result in high Decode Errors. The outcome of louder audio is an increase in errors.

Decode errors are for digital systems and the audio level should have no impact on the errors as it it the same data bits that are received regardless of audio level coded in that data information.

Can you make another video, now when you have D-error configured to the display, and make it longer to let us see what actually are happening?

/Ubbe

 

[n1moy]

I don't have video equipment.

 

[Ubbe]

If you don't have ProScan then download that and you can use it free for a month. In that program you have a virtual control function that will show the scanners display on the PC. Then run something like screen recorder for the Edge browser, and there are similar programs for other browsers, that will record your screen to a small video file you can post.

/Ubbe