Static?

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Twister_2

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Why is the end of transmission and squelch static not so heavy as other bands? As soon as you get out of the air band, it is the same old heavy static. It is not because it is not a repeater.
 

GrayJeep

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Air band is AM. Nearly everything else is FM. The squelch circuits behave differently between the two modes.
 

kb2vxa

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On VHF static and atmospheric noise is almost nonexistent. It's not the squelch and it's not static you hear; it's random electrical noise (white noise) produced by the receiver itself, turn off the squelch and you'll hear a steady hiss. Due to the nature of AM vs. FM receiver circuitry internally generated noise sounds louder on FM.

For what it's worth, in a receiver signal to noise (S/N) ratio is more important than overall sensitivity so pay attention to published data on "quieting" levels. Just because it's sensitive you still can't hear weak signals through a lot of noise.
 

prcguy

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Could you elaborate on the "quieting" specs for AM receivers because I have never seen that listed. Quieting is a common term for FM receivers. Do you know that modern sensitivity specs for FM receivers take noise into account? A receiver that has a rated sensitivity of .25uv for 12dB SINAD is measuring the SIgnal quality in the presence of Noise and Distortion.
prcguy
On VHF static and atmospheric noise is almost nonexistent. It's not the squelch and it's not static you hear; it's random electrical noise (white noise) produced by the receiver itself, turn off the squelch and you'll hear a steady hiss. Due to the nature of AM vs. FM receiver circuitry internally generated noise sounds louder on FM.

For what it's worth, in a receiver signal to noise (S/N) ratio is more important than overall sensitivity so pay attention to published data on "quieting" levels. Just because it's sensitive you still can't hear weak signals through a lot of noise.
 

kb2vxa

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I placed the word "quieting" in quotes for a reason, that being Twister for one is not particularly technically oriented so he asked a very simple question. I answer on the level of the question and try not to speak above it for the sake of understanding.

Before someone fires the first shot I like to play catch with charged capacitors from time to time. Now who has their rubber gloves on? (;->)
 
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