Static?

Status
Not open for further replies.

Twister_2

Member
Feed Provider
Joined
Mar 1, 2008
Messages
617
Location
Dauphin County, PA
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

Member
Premium Subscriber
Joined
Jan 6, 2007
Messages
967
Location
N. Colo.
Air band is AM. Nearly everything else is FM. The squelch circuits behave differently between the two modes.
 

kb2vxa

Completely Banned for the Greater Good
Banned
Joined
Mar 22, 2005
Messages
6,100
Location
Point Pleasant Beach, N.J.
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

Member
Joined
Jun 30, 2006
Messages
15,228
Location
So Cal - Richardson, TX - Tewksbury, MA
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

Completely Banned for the Greater Good
Banned
Joined
Mar 22, 2005
Messages
6,100
Location
Point Pleasant Beach, N.J.
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? (;->)
 
Status
Not open for further replies.
Top