NYPD Harbor George (SOD)

Hi. What is the beep or boop tail at the end of Harbor George's transmissions?
Why does only their radio do this?

Yes, I have heard the same thing. I have heard it on other harbor units and ESU radios too. Not sure what it is. I'm assuming some sort of MDC1200.

It Could be a Kiss Off (letting the other party know that the mic is unkeyed) Just like a roger beep but softer toned

Or it Could be a New type of Radio Identifier to Other Radios on the Display who is Keying up

I know what you mean, it's like a side tone of some sort.

On some NYPD and EMS freqs there's a tone that sets off when a unit talks right before the central dispatcher ends their transmission. Anyone know what that tones is?

Danny37 said:

I know what you mean, it's like a side tone of some sort.

On some NYPD and EMS freqs there's a tone that sets off when a unit talks right before the central dispatcher ends their transmission. Anyone know what that tones is?

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Believe that's the sound of the override cutting in- for NYPD at least, any field radio when keyed up while a dispatch console is keyed up will kick the console off the air and begin its broadcast, overriding the console. It's an officer safety feature designed to let an officer send a 10-13 or other major message even if dispatch is in the middle of a long-winded sentence.

What you are hearing are the keying tones. 2175 guard tone followed by 1950 F1 function tone followed by 2175 LLGT(low level guard tone).

There is no override of field units over dispatchers audio. It's actually the opposite, the dispatchers audio has priority over other audio. There is a card on the voting comparator that sets the console as priority. If a unit in the field transmits while the dispatcher is transmitting the field unit will be heard in the dispatchers "select" speaker on the console which is inadvertently picked up by the dispatchers microphone.

The reason it sounds like it cuts the console off the air is a simple explanation: a lot of dispatchers use headsets. When the headset is used the audio that would normally be in the select speaker is pumped into the dispatchers war so it can not be picked up by the microphone. Most dispatchers unkey the console so units in the field can hear the transmission.

Thanks, I'm gonna see if I can record a clip and show you guys.

UPDATE:

Here was the tone I was talking about heard right when the clip starts.
http://youtu.be/C53vMCOr0O0

Yes that is the keying tone that was not notched out. It usually happens when the repeater is about to drop if the dispatchers keys up, the notch filters don't always catch it and that is why it is audible.

ff026 said:

Yes that is the keying tone that was not notched out. It usually happens when the repeater is about to drop if the dispatchers keys up, the notch filters don't always catch it and that is why it is audible.

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Correct me if I'm wrong, but I've this exact tone on some FDNY EMS frequencies as well.

You are probably hearing either the 1950 F-1 TX tone, as the 2175 is filtered out or the voting comparaters going back to squelched condition which send out a constant 2175. Why you hearing it only on the marine units could be the setting of a particular receiver that looks out over the Queens waterways. Or the other possibility is E&M tones on a particular phone line or microwave link.

Danny37 said:

Correct me if I'm wrong, but I've this exact tone on some FDNY EMS frequencies as well.

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It's a EIA standard it is used in nationwide. It's not exclusive to NYC.

This Isn't What My Question Was

Listen to SOD, Harbor George's radio makes a boop sound at the end of the transmissions; I've only heard it from that radio, no others on SOD or NYC systems, It's not the sound on the youtube clip. I'll try to record it.

I have heard it. I think what is happening is they have post MDC-1200 enabled on the radio. The side tone is probably enabled and the mic is picking up the side tone for a split second. I forget which radio but some or one radio does side tone on Post MDC-1200 My memory is foggy on that but I believe I saw it once.

Sorry SCV, I kinda asked another question over this thread. But I know what your talking about, there's no MDC that I hear. It's a "bloop" when harbor George begins to transmit. Has a feedback sound to it. Since it's fall/near winter it's gonna be hard to record it, but if I can I'll upload it.

It's mdc sidetone. All NYPD zones mute MDC at the repeater/ comparator end. Harbor George is doing pre MDC which is completly muted and what you are hearing is the side tone.

Cool, thanks!