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Scanner / Receiver Antennas For discussion of any type of receiving antenna used by a scanner or receiver base, mobile or handheld.

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  #1 (permalink)  
Old 08-19-2009, 7:17 PM
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Default Squelch??

Yet again the young Jedi Knight seeks knowledge from his Jedi master's.

What is Squelch?
What is it's function?
How does it work in reciption of a frequency?
Why is it when I change my antenna I have to change my set level of my Squelch?
Are Squelch settings or levels different for Analog and Digital?
What factors affect Squelch?
Is Squelch something like a gate or some type of flow control?
And is Squelch something that is really needed in radios?

Brian
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Old 08-20-2009, 12:06 AM
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Quote:
Originally Posted by Sjinndoawi View Post
What is Squelch?
It's a circuit to silence a receiver output until a valid signal causes it to open.

Quote:
Originally Posted by Sjinndoawi View Post
What is it's function?
Without a squelch circuit, a receiver will just output noise until actually receiving a signal. This gets annoying real quick.

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Originally Posted by Sjinndoawi View Post
How does it work in reciption of a frequency?
By silencing the receiver when no signals are present, it prevents the operator from turning off the receiver in frustration, thereby allowing reception.

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Originally Posted by Sjinndoawi View Post
Why is it when I change my antenna I have to change my set level of my Squelch?
Because you probably have your squelch set wrong. It should be set tight enough that it doesn't "chatter", but loose enough that it doesn't cause usable signals to remain muted.

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Originally Posted by Sjinndoawi View Post
Are Squelch settings or levels different for Analog and Digital?
Yes would be the short answer.

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Originally Posted by Sjinndoawi View Post
What factors affect Squelch?
Signal strength. Local noise levels. The particular receiver. Personal preference. Operator experience. Receiver application and location.

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Originally Posted by Sjinndoawi View Post
Is Squelch something like a gate or some type of flow control?
Yes, very much so.

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Originally Posted by Sjinndoawi View Post
And is Squelch something that is really needed in radios?
Unless you actually LIKE high levels of white noise blasting at you all day, yes. they're quite necessary. An unsquelched receiver will still receive signals. If the receiver is listening to something that is ALWAYS there (like, say, an FM broadcast station) then a squelch is not necessary. In a type of service where transmissions are sporadic and intermittent, like two-way radio, it becomes essential for operator sanity.
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Old 08-22-2009, 9:49 AM
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If you're monitoring P25 digital systems, you don't have to worry about the squelch.
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Old 01-11-2010, 8:34 PM
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Default Double Tap

Quote:
Originally Posted by Sjinndoawi View Post
Yet again the young Jedi Knight seeks knowledge from his Jedi master's.

What is Squelch?
What is it's function?
How does it work in reciption of a frequency?
Why is it when I change my antenna I have to change my set level of my Squelch?
Are Squelch settings or levels different for Analog and Digital?
What factors affect Squelch?
Is Squelch something like a gate or some type of flow control?
And is Squelch something that is really needed in radios?

Brian
I got one question, on some kewnwood radios, at the end of each tramission there is a tap on the squelch tail that is more or less a double tap. it sounds like two very fast very brief squelch openings- Im not sure but i think it might be somekind of system to improve the closure of another radio. Have you ever heard of this before?
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Old 01-11-2010, 8:43 PM
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Quote:
Originally Posted by Gezelle007 View Post
I got one question, on some kewnwood radios, at the end of each tramission there is a tap on the squelch tail that is more or less a double tap. it sounds like two very fast very brief squelch openings- Im not sure but i think it might be somekind of system to improve the closure of another radio. Have you ever heard of this before?
You are probably hearing reverse burst
Motorola® Reverse Burst & And Squelch
DPL / DCS Information
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Old 01-12-2010, 12:38 AM
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Originally Posted by nd5y View Post
You are probably hearing reverse burst
Motorola® Reverse Burst & And Squelch
DPL / DCS Information
Hmm thats weird- I mean I live in yamhill county and the channel that I hear it on is the Common Mutual Aide Channel which everyone has in their radios and the audio quality is really finite compared to all the other channels that they are usually transmitting on. At first I thought it was some other form of audio that was lesser than anaglog. But yea, no idea. Thanks though!
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Old 11-01-2010, 3:59 PM
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This is old, but if the link works, here is a sample of what the 'tap' sounded like, the area has since moved on to a newer system, but in Corvallis, OR, Oregon State Police has a similar sounding repeater at the Oregon State University station.

tap demo.zip
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