Repeater Off-Sets are different with HAM.

[TNFrank]

I've also noticed kind of a pattern for CTCSS tones for each band. Not every repeater follows the pattern but I'd say a good 80-90% of them do. Has anyone else noticed this?

[SteveShannon]

3 minutes ago, TNFrank said:

I've also noticed kind of a pattern for CTCSS tones for each band. Not every repeater follows the pattern but I'd say a good 80-90% of them do. Has anyone else noticed this?

No, I haven’t noticed. 

[WRXB215]

Your title says "offsets" but then, in the body of your message, you talk about CTCSS. Which one is it and what pattern do you think you are seeing?

[dosw]

2 hours ago, TNFrank said:

I've also noticed kind of a pattern for CTCSS tones for each band. Not every repeater follows the pattern but I'd say a good 80-90% of them do. Has anyone else noticed this?

While the choice of CTCSS tones is not entirely random, it may as well be. There are common conventions, like avoiding adjacent tones in a given overlapping area, avoiding tones that are harmonics of power lines, that sort of thing. I think in some cases it's more about "legacy conventional wisdom" than about "real world issues in 2025." But as far as repeaters following a pattern, what you might be seeing is either a freak coincidence, or regional conventions that may have some historical rationale. Not any broadly adopted pattern.

[tweiss3]

1 hour ago, dosw said:

While the choice of CTCSS tones is not entirely random, it may as well be. There are common conventions, like avoiding adjacent tones in a given overlapping area, avoiding tones that are harmonics of power lines, that sort of thing. I think in some cases it's more about "legacy conventional wisdom" than about "real world issues in 2025." But as far as repeaters following a pattern, what you might be seeing is either a freak coincidence, or regional conventions that may have some historical rationale. Not any broadly adopted pattern.

Actually, your local repeater coordination body (typically won't answer anything and are useless), have recommended tones (2-5 of them) for each region of the area which they coordinate. These are Ohio's recommendations, not requirements, but it keeps adjacent pairs from using the same tones.

[WRXB215]

Kudos to @dosw and @tweiss3 for understanding the question and providing good answers.

[TNFrank]

Most of the 2M repeaters in my area use 162.2 as their CTCSS, the 1.25M seem to use 156.7 and the 70cm use 100.0 for their CTCSS. I guess my 'Tisim saw a pattern in this and wondered if anyone else noticed.

[SteveShannon]

20 minutes ago, TNFrank said:

Most of the 2M repeaters in my area use 162.2 as their CTCSS, the 1.25M seem to use 156.7 and the 70cm use 100.0 for their CTCSS. I guess my 'Tisim saw a pattern in this and wondered if anyone else noticed.

Montana has 145 ham repeaters:

One 10 meter, no tones

Two 6 meter, no clear pattern  

Eighty 2 meter, majority 100 Hz tone

Two 220 MHz, no clear pattern

Fifty-nine 70 cm, majority 100 Hz tone

One 900 MHz, no clear pattern

I don’t detect any pattern other than the vast majority of 2 meter and 70 cm use 100 Hz in this state. 

[tweiss3]

33 minutes ago, TNFrank said:

Most of the 2M repeaters in my area use 162.2 as their CTCSS, the 1.25M seem to use 156.7 and the 70cm use 100.0 for their CTCSS. I guess my 'Tisim saw a pattern in this and wondered if anyone else noticed.

Well, SouthEast Repeater Association (the TN coordination body) has recommended tones.

100.0 is the common, and if you are on the edge of TN middle and TN east, what you notice is on purpose......

[Davichko5650]

On 8/25/2025 at 2:05 PM, TNFrank said:

I've also noticed kind of a pattern for CTCSS tones for each band. Not every repeater follows the pattern but I'd say a good 80-90% of them do. Has anyone else noticed this?

Might be a regional thing, like around here>  A common one for many of the local 2m repeaters in the TC area of MN is 114.8. a couple exceptions but I'd say about 85-90% or more here are using 114.8.

[dosw]

Utah VHF Society (band plan manager for Utah; utvhfs.org) lists 429 repeaters. Of those, 292 use tones, and 137 do not. There are, from what I can tell, 29 tones used by those 292 repeaters, with the most common being a simple 100.0. There doesn't seem to be any specific rhyme or reason other than obvious things like most (but not all) of the Intermountain Intertie linked repeaters using the same tone. There's no pattern other than the sometimes-used concept of "similar things should be [conveniently] similar", as in the example of the Intertie network.

 

There's a pretty good explanation for why you might see a pattern. Humans seek patterns in random events due to apophenia, a common cognitive tendency to find meaning and order in randomness, which is rooted in an evolutionary advantage for survival. For our ancestors, a false positive in pattern recognition (seeing a predator in random leaves) was safer than a false negative (failing to see a real predator). This brain mechanism makes it easier to process information and make quick inferences, though it can lead to errors like misinterpreting data or believing in conspiracy theories.

 

(Explanation came from AI, which is probably ironic)