Fdny silmocast

[W2MR]

Sounds like the new FDNY UHF system uses multiple transmitters on the same frequency. I got curious and looked at the FCC license. I see one site for The Bronx for example. Are the other transmitters scattered around the other boroughs?

[tbendick]

There should be something like 12 sites around the city.

[comspec]

Wirelessly posted (BlackBerry9800/6.0.0.600 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/102)

I assume from this tread that there are people hearing FDNY on the UHF frequencies?

I have both the VHF and UHF programmed in but I am only hearing the VHF. Are the UHF frequencies active already?

[Chauffeur6]

The UHF frequencies have been active for over two years now. If you can't hear them on UHF, you're probably too far outside the city to pick up the signal. The VHF frequencies have a much greater range.

[ff026]

To the OP, the term is simulcast. Multiple transmitters on the same frequency. FDNY is using simulcast on UHF. They are multicasting on UHF and VHF. Multicast is 2 different frequency transmitting the same message.

[innokuous1]

I could be wrong, but I thought that a radio simulcast could occur on the same band and/or different bands, and that the term multicast was more related to the sending of computer messages from one computer to many computers simultaneously. Comments on this are welcome please.

[Thunderknight]

Originally Posted by innokuous1

I could be wrong, but I thought that a radio simulcast could occur on the same band and/or different bands, and that the term multicast was more related to the sending of computer messages from one computer to many computers simultaneously. Comments on this are welcome please.

Simulcast = same transmission on the same frequency at multiple sites. Transmitters are time-synchronized (usually by gps time) with slight (milliseconds) delay in transmission to minimize interference.

Multicast = same transmission on different frequencies (same or different bands). Similar to a patch.
For example, a fire dispatch that occurs on a trunked talkgroup and on a VHF paging channel at the same time.
It is also an IT term.

[W2MR]

Points off for spelling? I meant "simulcast".

[innokuous1]

I found this:

Definition check: Simulcast