FDNY UHF Radios Question?

[jacobsmith]

Is FDNY using the UHF radio system full time yet? Will the backround noise be cut out once they move the the UHF system? The one that is louder then when some one talks becomes less loud then when they're done talking becomes loud again. Thanks. (kind of like Chicago's system has) what is that caused by?

 

[zerg901]

I think you are talking about a live scanner feed. Sometimes it is hard to get good audio levels on the feeds. You might want to drop a note to the feed provider with your questions.

If you are talking about messages received over the air to your scanner, maybe they have some problems with their audio quality. Or maybe you are getting interference on the signal.

 

[tbendick]

We have 7 systems in use today.

VHF Fire (old system)
UHF Fire Narrowband
UHF EMS (old system)
UHF EMS Narrowband
UHF Trunked
800mhz Trunked
UHF Simplex for fireground.

 

[newsnick175]

I believe FDNY's "narrowband" is a missnomer. The frequency is right [ie: 482.06125] but they are still using 25Khz, not 12.5Khz. Right?
Any way, trying to listen to the fireground HT traffic is a real pain. It seams that no one puts the mike in frount of their faces when they talk! Now there's background noise!

 

[tbendick]

All the new stuff should be set at 12.5 except maybe fireground.

There are alot of guys.you talk into the air instead of the mic.
Pain we you have your ear to the speaker and then the mdc style id is at full volume

 

[902]

Is FDNY using the UHF radio system full time yet? Will the backround noise be cut out once they move the the UHF system? The one that is louder then when some one talks becomes less loud then when they're done talking becomes loud again. Thanks. (kind of like Chicago's system has) what is that caused by?

That's called compression. When there's no speech, an automatic gain control circuit or (nowadays) a software algorithm brings up the background volume. The main purpose is to keep speech output at a constant level even though its input levels may vary.

All systems have compression settings and some narrowbanding systems have compandoring (compression and expansion), but these are critical adjustments that are optimized to the user's needs.

Someone else will have to answer the specifics of how the Channel 16 conventional systems are set.