Ocean County 700MHZ Fire Ground channels (Simplex)

[fireman_dude]

CONFIRMED....
Fire ground 1 769.03125
Fire ground 2 769.04375
Fire ground 3 769.89375
Fire ground 4 769.99375
Fire ground 5 773.50625

 

[lynchy135]

You should submit this to the DB.

 

[fireman_dude]

You should submit this to the DB.

Good Idea. Will do.

 

[GTR8000]

What PL/DPL is in use on these channels?

 

[fireman_dude]

What PL/DPL is in use on these channels?

I have no way of knowing that. I got this information by using one of our station's portables and Close Call monitoring on a scanner.
Toggled through the fire ground channels and keyed up. Wrote down the Fq's.

 

[GTR8000]

The scanner will normally display the decoded PL or DPL in Close Call mode.

 

[nd5y]

Those are all either national interoperability channels or regional low power channels.
They are already in the DB here.

National Interoperability (United States) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for National Interoperability (United States)

www.radioreference.com

 

[fireman_dude]

Those are all either national interoperability channels or regional low power channels.
They are already in the DB here.

National Interoperability (United States) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for National Interoperability (United States)

www.radioreference.com

You are correct. I was wondering why I could never find these under the Ocean County database.
Mystery solved.

 

[GTR8000]

Those are all either national interoperability channels or regional low power channels.
They are already in the DB here.

National Interoperability (United States) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for National Interoperability (United States)

www.radioreference.com

Well no, not quite the same thing. The nationwide listings are for P25 mode, however the regional and nationwide low power 700 MHz channels are permitted to be licensed for analog operation. As long as the usage is local and there is a unique PL/DPL in use, they will be listed under the county.

 

[GTR8000]

You are correct. I was wondering why I could never find these under the Ocean County database.
Mystery solved.

This is why we need to know if there is a PL/DPL in use. First of all, so we can figure out if these are analog or digital (P25) usage, and because it's an incomplete submission without the details of whatever tone (PL, DPL, NAC) is in use.

 

[GTR8000]

@elias1988 Any insight into these channels?

 

[E5911]

I did not think you could run these frequencies as analog, too narrow I thought 6.25k aren't they?

 

[elias1988]

@elias1988 Any insight into these channels?

I have no access to the new radios at this point.

 

[E5911]

I stand corrected, however I still think these are 6.25k ultra narrowband

The Narrowband segment consists of 1920 6.25 kHz-wide channels operating as 960 pairs. Subject to compliance with spectrum usage efficiency requirements, licensees may combine two to four contiguous narrowband channels (6.25 kHz) to form 12.5 kHz and 25 kHz bandwidth channels. These channels are allocated into seven distinct groups and are governed by rules which are codified at 47 C.F.R. Part 90, Subpart R.

 

[GTR8000]

I did not think you could run these frequencies as analog, too narrow I thought 6.25k aren't they?

I stand corrected, however I still think these are 6.25k ultra narrowband

The Narrowband segment consists of 1920 6.25 kHz-wide channels operating as 960 pairs. Subject to compliance with spectrum usage efficiency requirements, licensees may combine two to four contiguous narrowband channels (6.25 kHz) to form 12.5 kHz and 25 kHz bandwidth channels. These channels are allocated into seven distinct groups and are governed by rules which are codified at 47 C.F.R. Part 90, Subpart R.

Yes, the band plan technically breaks up 769-775 into 6.25 kHz channels, however the 700 MHz narrowband spectrum is overwhelmingly licensed as 12.5 kHz wide channels. 6.25 kHz is not really a thing, as there is no P25 support for that bandwidth, and NXDN is not used in the 700 band. The spectrum was supposed to eventually be ultra-narrowbanded to 6.25 kHz, but that was nixed by the FCC. Don't confuse "6.25 kHz efficiency" of TDMA with actual 6.25 kHz bandwidth.

47 CFR § 90.531 covers all of this in detail, in particular the section on combining channels for 12.5 or even 25 kHz operation. Look at any 700 MHz SG license that has analog emissions, and they are all 11K bandwidth.

 

[fireman_dude]

The scanner will normally display the decoded PL or DPL in Close Call mode.

Hope this helps.

 

[GTR8000]

Hope this helps.

It does, thanks. Is the same 4C9 NAC being used on all 5 channels?

 

[Frequency1]

It does, thanks. Is the same 4C9 NAC being used on all 5 channels?

Yesterday I picked up LBI companies talking on Fireground 4 (769.99375).
The NAC was 79Eh on Fireground 4.
Another RR member confirmed Fireground 5 NAC is 4C9.
Are these two NACs actually the same and it’s how I have my SDS100 set up?
Or these NACs completely different?

 

[GTR8000]

Yesterday I picked up LBI companies talking on Fireground 4 (769.99375).
The NAC was 79Eh on Fireground 4.
Another RR member confirmed Fireground 5 NAC is 4C9.
Are these two NACs actually the same and it’s how I have my SDS100 set up?
Or these NACs completely different?

4C9 and 79E are not the same, no. It's possible that your SDS was giving a false decode. Do you have 4C9 NAC programmed for all of the fireground channels, or do you have them in NAC Search mode? I've seen the SDS series flash a false NAC from time to time when in search mode.

 

[Frequency1]

4C9 and 79E are not the same, no. It's possible that your SDS was giving a false decode. Do you have 4C9 NAC programmed for all of the fireground channels, or do you have them in NAC Search mode? I've seen the SDS series flash a false NAC from time to time when in search mode.

Yes, those fireground frequencies are in NAC search.
I recorded 4 quick transmissions, all showed 79E. But yes, I’m familiar with what you’re saying about false NACs on SDS.
I’ll continue recording and double and triple check before submitting anything new to the database. Thanks GTR8000