Nationwide P25

[Darkstar350]

Aside from 700mhz - Is P25 allowed on any of the nationwide interop/"common public safety" channels?

Because i have picked up P25 more then a few times on one of the narrowband non 700 freqs on this page - Interoperability Scanner Frequencies and Radio Frequency Reference

I think the frequency in question is 158.7375 and being that it is narrow from what i understand (for example) while the actual frequency may be 158.7500 when a frequency such as 158.7375 is programmed it may receive 158.7500 in the radio itself so in other words i suppose its possible that i could be receiving a P25 frequency that is close on either side of .7375...

 

[nd5y]

It is allowed but does not appear to be recommended. All references to P25 on the VHF/UHF/800 channels was removed from the NIFOG a few years ago. Several years ago Texas mandated that all interop communications in the state were going to be P25 but they dropped that plan.

There are legacy licensees in some areas that use the national interop channels for normal use. That could be what you are hearing. It is also possible that a planned event could use pre coordinated encrypted P25 on the interop channels.

 

[ecps92]

I have seen in some Radios the use of P25 $293 in the VHF Part 90 Interops.
All end with "P" in the alpha tag

Example of a 16 channel Layout

Channel Name RX RX Tone TX TX Tone
1 VLAW31 155.4750 156.7 155.4750 156.7
2 VLAW31P 155.4750 $293 155.4750 $293
3 VLAW32 155.4825 156.7 155.4825 156.7
4 VLAW32P 155.4825 $293 155.4825 $293
5 VCALL10 155.7525 156.7 155.7525 156.7
6 VCALL10P 155.7525 $293 155.7525 $293
7 VTAC11 151.1375 156.7 151.1375 156.7
8 VTAC11P 151.1375 $293 151.1375 $293
9 VTAC12 154.4525 156.7 154.4525 156.7
10 VTAC12P 154.4525 $293 154.4525 $293
11 VTAC13 158.7350 156.7 158.7350 156.7
12 VTAC13P 158.7350 $293 158.7350 $293
13 VTAC14 159.4725 156.7 159.4725 156.7
14 VTAC14P 159.4725 $293 159.4725 $293
15 VMED28 155.3400 156.7 155.3400 156.7
16 VMED29 155.3475 156.7 155.3475 156.7

It is allowed but does not appear to be recommended. All references to P25 on the VHF/UHF/800 channels was removed from the NIFOG a few years ago. Several years ago Texas mandated that all interop communications in the state were going to be P25 but they dropped that plan.

There are legacy licensees in some areas that use the national interop channels for normal use. That could be what you are hearing. It is also possible that a planned event could use pre coordinated encrypted P25 on the interop channels.

 

[Darkstar350]

Ah ok - so the answer basically is "yes and no"
Makes sense in the respect that if x and y agency are operating "on scene" using low power mobiles/portables with p25 on the interop channels then (while not exactly a standard) it wouldnt really matter as much whereas actually setting up repeaters and infrastructure for P25 on the nationwide channels(with the exception of 700mhz) is generally discouraged...
Yeah i am aware that some agencies actually may happen to use some of these frequencies as their day to day/main channels - i even pick up some distant police or fire departments toning out for what sounds like routine dispatch from time to time (I know that the nationwide freqs are definitely not intended for that but i suppose there could be exceptions with "grandfather" licenses, etc)

So far i have really only noticed the p25 on that one channel but it stood out to me because these channels arent really used much as it is let alone with P25...

 

[mmckenna]

That's VTAC34, one of the "Non-Federal VHF National Interoperability Channels". IFOG recommends analog,

VTAC34 is "recommended for deployable tactical repeater use only", again, according to the IFOG.

And again with the IFOG (2011) quote:

Regulations and Guidelines for National Interoperability
......
3. Digital P25 operations on non-Federal interoperability channels should transmit the default Network Access Code (NAC) &293, and receive with NAC $F7E (accept any incoming NAC). Specify talkgroup $FFFF, which includes everyone.

 

[nd5y]

That's VTAC34, one of the "Non-Federal VHF National Interoperability Channels". IFOG recommends analog,

VTAC34 is "recommended for deployable tactical repeater use only", again, according to the IFOG.

And again with the IFOG (2011) quote:

What is IFOG? Do you mean NIFOG or a state guide from some state that begins with I? If you have something from 2011 it is probably obsolete. The latest NIFOG is 1.6 which was released in May 2015.

158.7375 can be VTAC13 if simplex or VTAC33, 34, 37 or 38 if it is a repeater and depending on if it is the input or output and which other frequency it is paired with.

 

[mmckenna]

NIFOG, and the 2011 version is what I have sitting here on my desk. I've got the latest one downloaded, but not the laminated/spiral bound one that DHS usually sends out to us.

 

[hitechRadio]

Here ya go. NIFOG 1.6

https://casmnextgen.com/pslib/index.php/webview?docid=108

 

[Jay911]

Actually P25 CAI is mandated on the 700 MHz frequencies. There should be a reference in NIFOG on the top of page 43 stating that.