SDR# Frequency Scanner beep

[TDR-94]

When using the Frequency Scanner I sometimes get a loud single tone beep,when it stops on a frequency in a certain part of the search range.What does the beep indicate?

 

[thewraith2008]

If using the latest version (v2.2.8.0), the beep indicates a problem with frequency tuning.
- Request made to SDR# to tune to frequency, scanner checks that expected frequency has been tuned too. If not then beep.

Why is it occurring?
Possibly the 'Detect' value is too low (and the scan-rate is too quick) not giving the SDR#/dongle enough time to tune.
Call to RTL driver (if using RTL dongle) did not return successfully. (did not tune). The SDR# RTL frontend is a bit on the simple side when handling driver errors.
May occur when CPU load is high.
Some other reason that I haven't determined.
I added beep to detect when it occurred, but it rarely did for me so I have not investigated it more. This maybe due to the fact I use a custom SDR# RTL frontend/driver.

 

[TDR-94]

If using the latest version (v2.2.8.0), the beep indicates a problem with frequency tuning.
- Request made to SDR# to tune to frequency, scanner checks that expected frequency has been tuned too. If not then beep.

Why is it occurring?
Possibly the 'Detect' value is too low (and the scan-rate is too quick) not giving the SDR#/dongle enough time to tune.
Call to RTL driver (if using RTL dongle) did not return successfully. (did not tune). The SDR# RTL frontend is a bit on the simple side when handling driver errors.
May occur when CPU load is high.
Some other reason that I haven't determined.
I added beep to detect when it occurred, but it rarely did for me so I have not investigated it more. This maybe due to the fact I use a custom SDR# RTL frontend/driver.

Ok,thanks.

I'm currently still using (v2.2.5.0) with v1716 and the Airspy R2, but I'll check those suggestions and see if I can narrow down when and if it happens again. Could setting the red line just below 10 also cause this?

 

[thewraith2008]

Ok,thanks.

I'm currently still using (v2.2.5.0) with v1716 and the Airspy R2, but I'll check those suggestions and see if I can narrow down when and if it happens again. Could setting the red line just below 10 also cause this?

The beeps where used for different things in older versions, I don't remember what they are now. (maybe one was when Now play file write error)

I doubt red line has any impact here.

If the error is the tuning of the frequency, this should not be a problem as the plug-in should retry tuning the seqment anyway.
I will remove the audible beep from next release as it was only for debugging.

 

[TDR-94]

I've noticed that when I pause the Frequency Scanner on a frequency, that before every transmission, there is a short period/burst of noise right before you hear the beginning of the audio. Is there a setting that prevents the noise burst before the audio? I tried adjusting the Auto Mute controls,but that doesn't seem to make any difference.

If I don't use the Frequency Scanner and just have a frequency manually tuned, in SDRsharp, with the squelch setting adjusted, there is no burst of noise before every transmission like there is when the same frequency is paused in the Frequency Scanner.

 

[TDR-94]

I found a video that another forum member "batdude" posted in another forum,that shows starting at about 22 seconds into the video, something else that I noticed happens frequently on my set-up. Many times the Frequency Scanner will lock onto a transmission and you will hear the audio,but then the reply will be muted. In the video you can see the reply transmission signal on the spectrum display,but the audio isn't coming through.

This also happens frequently with my set-up when the Frequency Scanner is paused on a frequency. I will hear the reply transmission on my IC-R20 clean and clear.On SDR# you will see the reply transmission signal,but there is no audio. It seems random in nature when it happens.

Is this a result of particular settings or is it a bug?

 

[thewraith2008]

I've noticed that when I pause the Frequency Scanner on a frequency, that before every transmission, there is a short period/burst of noise right before you hear the beginning of the audio. Is there a setting that prevents the noise burst before the audio? I tried adjusting the Auto Mute controls,but that doesn't seem to make any difference.

If I don't use the Frequency Scanner and just have a frequency manually tuned, in SDRsharp, with the squelch setting adjusted, there is no burst of noise before every transmission like there is when the same frequency is paused in the Frequency Scanner.

Try looking at the option 'Noise protection delay' ON/OFF values.

I don't know about other problem you have.
Sort of sounds like the problem that existed if you used the SDR# squelch with the 'Audio mute' option in the plug-in.
The plug-in now switches off the SDR# squelch if 'audio mute' option is used so that should not occur.

 

[TDR-94]

Try looking at the option 'Noise protection delay' ON/OFF values.

I notice no difference in changing those settings. I can put them both at their max setting of 20 and notice nothing different than setting them both at 1 or any other value in between.

Is there a preferred method of "testing" the Noise Protection Delay settings where I can see what effect they have?

 

[thewraith2008]

'Noise protection delay' default ON/OFF values are 5/3.

From the issue your seeing, adjusting the OFF value should be all that is needed.

OFF: This will delay the un-muting action of the SDR# mute after the scanner stops on an active frequency.
ON: This will delay the muting action of the SDR# mute after signal activity was seen.

The 'crashes' can be more noticeable on NFM rather than AM when adjusting these values as AM can be a 'quieter'.

Should be noted that these options won't help if the 'crashes' are occurring on a frequency that is a repeater downlink and where repeated 'overs' are heard with the 'crash'. This issue is occurring on the repeater RX radio and transferred to the TX radio.

 

[TDR-94]

'Noise protection delay' default ON/OFF values are 5/3.

From the issue your seeing, adjusting the OFF value should be all that is needed.


The 'crashes' can be more noticeable on NFM rather than AM when adjusting these values as AM can be a 'quieter'.

Should be noted that these options won't help if the 'crashes' are occurring on a frequency that is a repeater downlink and where repeated 'overs' are heard with the 'crash'. This issue is occurring on the repeater RX radio and transferred to the TX radio.

I've been primarily using the Frequency Scanner for the VHF/UHF AM airbands. I'll try searching some local HAM frequencies, with the Frequency Scanner, and try adjusting the Noise Protection Delay settings to see if I can notice a noticeable difference.

The short period of noise I hear, before each voice transmission, when paused on an AM frequency in the Frequency Scanner, sounds similar to white noise. The best that I can describe it is like a noise gate is not "clamping down" quick enough on the noise before the voice transmission.