Hello all. I just noticed that when I turn the squelch to zero, the scanner, SDS200, continues to scan, but the scan speed is a great deal slower, and it stops on active frequencies. I would have thought that turning the squelch off would stop the scan and i would hear open squelch noise. Has anyone else found this?
SDS100/SDS200: Odd SDS200 Squelch Behavior
- Thread starter PCTEK
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- Joined
- Feb 22, 2007
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- 6,156
It all depends if it's a conventional frequency protected by Tone squelch or if it's a system. If it's a conventional frequency like Marine radio then scanning will stop and the squelch will be open with static.
This is normal squelch behavior on an sds-200. Best to always leave the squelch on 2.
The channels are local PD & FD, all of which have CTCSS tones. I always have the SDS200 squelch set at 2, except in this instance.
No biggie, i just thought it was odd.
No biggie, i just thought it was odd.
- Joined
- Feb 22, 2007
- Messages
- 6,156
CTCSS acts as squelch. The only thing that will open it is the tone it is set at. When I noticed with the SDS series was in the beginning before the filter firmware additions and other firmware improvements, that it was recommended to open the squelch on p25 simulcast systems with transmissions being clipped, missed or broken and on one of those systems if you turn the squelch off it will slow the scanning down and make it inconsistent.
It will do that also with conventional frequencies PL tone protected. It's normal.🙂
Ubbe
Member
It's two different detect systems in work, one carrier detect that just checks if there's a signal on the frequency and its level are controlled by the squelch setting, and there's another that goes from what subtone or digital mode you have set.
It will try and decode subtone or digital signals during something like a 250mS time and then give up and go to the next frequency and scan rate will be 4ch/s if the squelch are set to 0, and you only scan systems that use a subtone or use a digital mode.
If it doesn't detect any carrier then it will be no need to check if subtone or digital settings have a match. If the squelch would close during a conversation, it can do that if it receives interference or modulation from the signal are too wide, it will also stop the subtone or digital decode and perhaps continue to scan. To stop that from happening you can set squelch to 0, if you only scan one or two frequencies or sites.
/Ubbe
It will try and decode subtone or digital signals during something like a 250mS time and then give up and go to the next frequency and scan rate will be 4ch/s if the squelch are set to 0, and you only scan systems that use a subtone or use a digital mode.
If it doesn't detect any carrier then it will be no need to check if subtone or digital settings have a match. If the squelch would close during a conversation, it can do that if it receives interference or modulation from the signal are too wide, it will also stop the subtone or digital decode and perhaps continue to scan. To stop that from happening you can set squelch to 0, if you only scan one or two frequencies or sites.
/Ubbe
