Effectiveness of frequency skipping features like Sound Squelch or Data Signal Skip

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Jun 7, 2016
Two examples of this used by Radio Shack (GRE/Uniden) are:

1) Sound Squelch - keeps the scanner from stopping on frequencies with only a carrier signal and no voice or other sound, so you can hear calls instead of stopping on silence. Used on Flagship radios like the PRO-2004/2005/2006 or PRO-2035/2042.

2) Data Signal Skip - To prevent a scanner from stopping on frequencies that consist of non-modulated or data signals like fax, data signals or modem transmissions during searching or scanning. Used on Flagship radios like the PRO-2052.

I found in the past when I owned a PRO-2004 that the Sound Squelch worked very well. If a frequency was transmitting but with no audio, it would just skip right over it most of the time but if it had any noise on the signal it would not work. That would fool it into thinking it was audio. This works almost the opposite of the Data signal Skip function.

The Data Signal Skip feature should stop on normal voice signals or even signals with no audio but skip things like tones, data signals, etc. It has to do with the waveform of the audio. No audio or a voice like waveform like seen on a scope would be ok but a tone or data that would be a more constant signal.

I just recently used a Radio Shack PRO-2052 and also talked to others that also had this feature on other scanners like the PRO-2040. I found that I could never find a signal that it would work on and other people I talked to said the same.

It's too bad this feature don't work because it has lots of useful applications. One that I've heard of is monitoring Analog EDACS or LTR trunking systems with limited traffic if you don't own a trunking scanner. You would program the trunking frequencies into 1 scan bank and the scanner would skip over the data channel and any other data signals but stop on only voice signals. You would only scan that bank. A trunking system with limited traffic would probably not have enough users to be always using the system at the same time and the limited frequencies would let the scanner find a follow up to the call even on a different channel. You could also program in the lowest frequency and highest frequency if they are closely spaced and do a search.

It would also be good just to skip over control channels of trunking frequencies when searching for conventional frequencies.

From my experience, I would rate Sound Squelch at 75% effective and Data Signal Skip at 0%.

ICOM also has a similar feature called VSC (voice squelch control) function. If a receiver signal includes voice components, and the tone of the voice components changes within 1 sec.,squelch opens. If the received signal includes no voice components or the tone of the voice components does not change within 1 sec., squelch closes. This is also somewhat effective and does work.

Please note that using these features can slow down your scan or search speed.
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