NIFOG - Observation

[WRXR255]

Had the day to myself and no tasks to accomplish, so I was browsing through the NIFOG (National Interoperability Field Operations Guide) and programming a radio with the stuff that might be interesting to listen to or have in an emergency to try to get info.

Anyway, as I am programming these in, I just noticed how some of those have some truly weird offsets.

We know that GMRS usually uses a +5.0 for repeaters, and on HAM its got its usual, so it was just interesting to see a -4.6725, and +0.735 among others.

Im sure there was a reason for those offset values, but I did find it interesting.

[OffRoaderX]

1 hour ago, WRXR255 said:

We know that GMRS usually uses a +5.0 for repeaters

ALWAYS.. GMRS always uses +5 for repeaters.

[MarkInTampa]

26 minutes ago, OffRoaderX said:

ALWAYS.. GMRS always uses +5 for repeaters.

Not always.... The strongest by far repeater in my neck of the woods on 462.575 has two input frequencies - 467.575 AND 467.725 on a different PL. The repeater gets interference on occasion when ships are in port that use 467.575 and they have to shut down the primary input, but both normally run at the same time. There are a few GMRS channels that are also shared  for on-board vessel communications, in particular 467.550 and 467.575 (the one we get interference on) and is legal per ITU regulations.

 

[OffRoaderX]

14 minutes ago, MarkInTampa said:

Not always

Yes, always.  If it is not +5, then it is not, by definition, "GMRS".

But I get what you're saying.

[MarkInTampa]

24 minutes ago, OffRoaderX said:

Yes, always.  If it is not +5, then it is not, by definition, "GMRS".

But I get what you're saying.

What's sad is if they do have to disable the primary input, it then kills off 3/4's of the users as well for a few days at a time. Their radios don't support a custom split of 462.575/467.725 and/or split tones (DPL on input/CTCSS on out) but most just don't know about the secondary input. The secondary info is posted on the repeater website (but NOT MYGMRS website) and is the recommended frequency to use. They just kinda freak out thinking their radios aren't working when they can receive but not transmit to a repeater that was working the day before.

[WRXR255]

18 minutes ago, OffRoaderX said:

Yes, always.  If it is not +5, then it is not, by definition, "GMRS".

But I get what you're saying.

Hence why I said "usually".

I debated on how I worded my original post on that wording actually, but not everyone does things by definition, so it was like OK, i get beat up by those that do it different, or i get beat up by those that say its the only way.

I was screwed either way.

[SteveShannon]

It's possible to be slightly off from 5.000 MHz and still be well within the rules for GMRS.  It's nitpicking, but there's nothing in the rules that specify a 5 MHz offset.  What is required is that the repeater input frequencies come from the 467 MHz main channels and that repeaters transmit only on the 462 MHz main channels.

But, doing that breaks the repeater channels for all certified 95E radios.

[gortex2]

800Mhz use -45mhz and VHF there is no standard split. Also remember the NIFOG channels are programemd in Commercial LMR Part 90 radios. They dont ask for splits, they ask for frequency. 

[BoxCar]

1 hour ago, gortex2 said:

800Mhz use -45mhz and VHF there is no standard split. Also remember the NIFOG channels are programemd in Commercial LMR Part 90 radios. They dont ask for splits, they ask for frequency. 

Yup. We assigned what was available. Requests often came into our shop with frequencies specified but couldn't be used because someone else was already using it as a repeater input. For LMR, repeater outputs are listed on licenses but not inputs.