Thorny41587
Member
I was listening to ham band today, and they were saying how the repeater was weaker than normal, he said, "I can tell it's de-sensing the scanner". What does de-sensing mean?
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nd5y
Member
OK after over 20 years in scanning.. thats a new one on me....
I can understand if they said "overloading", or "losing lock", or heck, even "losing squelch"...... but desensing....... *Shakes head*
Must be thier version of saying its not a strong enough signal to "break squelch" on the scanner????
I can understand if they said "overloading", or "losing lock", or heck, even "losing squelch"...... but desensing....... *Shakes head*
Must be thier version of saying its not a strong enough signal to "break squelch" on the scanner????
Thorny41587
Member
RE:
Thanks
Thanks
And I learn something new everyday.... THANKS for the website...
N
N_Jay
Guest
milf said:
Desense is a very specific effect.
Not saying that the Ham was using it correctly or not.
nd5y
Member
N_Jay said:
You got that right! I hear hams (and public safety) pretty often
attempting to sound smart by using "big words" that don't make any sense.
Tom
Still waiting on one of them to say I got a new rig that can "supercalifragilisticexpialidoscious" on all bands.....
WEG
WEG
N_Jay said:
OK. I'll say it. He was most likely using the term incorrectly.
You CANNOT desense a receiver that is on the same frequency as the offending transmitter. It's a technical impossibility.
Desense is the desensitization (the real form of the word) of a receiver to radios signals due to a strong nearby transmitter emission. What happens is the transmitter effectively blocks the weak signal you are trying to receive - very much like someone shouting in your ear while you are trying to hear a distant whisper. That's an extreme example, but it does get the point across.
He likely meant that the signal was weak or not breaking the squelch. In either case, the signal was not strong enough to receive and really couldn't desense the receiver if it were on an adjacent frequency.
The only way it could have been desensing his scanner by being weaker than normal is if it were putting out spurs that were on frequencies near those the guy was trying to hear on his scanner. Spurs use transmitter power and reduce the strength of the intended frequency's carrier. So, the TX could have been weaker, and the spurs were causing the desense, but I seriously doubt this was the case.
Joe M.
kc4jgc
Member
I agree that the term was probably used incorrectly.
To make it simple:
Desense refers to a station listening to a frequency while another station nearby on an adjacent freq is transmitting. The strength of the transmitting station is unsually enough to affect the reception of the first station on his freq by a noticable drop in strength of the signal he/she is recieving. Once the transmitting station stops, the signal strength of the signal the first station is recieving returns to normal.
A common situation would be 2 mobiles talking to each other on the same repeater. If the 2 mobiles were to come close to each other (maybe 1/4 mile or less apart), thier transmissions (on the repeater input freq) would begin to desense each other's recievers (on the repeater output freq). The 2 mobiles would notice a "hiss" on the recieve as well as the recieved signal level from the repeater would be degraded.
Hope that explanation helps.
Steve
To make it simple:
Desense refers to a station listening to a frequency while another station nearby on an adjacent freq is transmitting. The strength of the transmitting station is unsually enough to affect the reception of the first station on his freq by a noticable drop in strength of the signal he/she is recieving. Once the transmitting station stops, the signal strength of the signal the first station is recieving returns to normal.
A common situation would be 2 mobiles talking to each other on the same repeater. If the 2 mobiles were to come close to each other (maybe 1/4 mile or less apart), thier transmissions (on the repeater input freq) would begin to desense each other's recievers (on the repeater output freq). The 2 mobiles would notice a "hiss" on the recieve as well as the recieved signal level from the repeater would be degraded.
Hope that explanation helps.
Steve
STiMULi
Member
Answer
Thorny41587 said:
Maybe he meant that HE was able to desense the scanner (not that the repeater was desensing it) and that the repeater was not strong enough to overcome the desense and still make it into the scanner fully quieted while he was transmitting.
Joe M.
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