WEBVTT NOTE The Thirty Channels 1 00:00:00.000 --> 00:00:07.801 Forget the channel numbers for ten minutes. Your radio shows channels 1 to 22. 2 00:00:07.801 --> 00:00:29.805 The FCC's rules contain no such numbering, section 95.1763 lists frequencies, in four groups, and the group a frequency belongs to determines its power limit, its bandwidth, and which kinds of station may transmit on it. 3 00:00:29.805 --> 00:00:45.808 Learning the four groups makes the channel numbers fall out for free. Learning the channel numbers teaches you nothing about the rules. There is a diagram here. 4 00:00:45.808 --> 00:01:02.711 Four rows of channel markers on a frequency axis from 462.5 to 467.8 megahertz. The 462 megahertz main channels, eight of them from 462.5500 to 462.7250, allow 50 watts. 5 00:01:02.711 --> 00:01:19.413 Seven 462 megahertz interstitial channels sit between them at 5 watts ERP. Eight 467 megahertz main channels from 467.5500 to 467.7250 are repeater inputs at 50 watts. 6 00:01:19.413 --> 00:01:28.915 Seven 467 megahertz interstitial channels are limited to 0.5 watts ERP and handheld units only. 7 00:01:28.915 --> 00:01:31.038 The four groups. 8 00:01:31.038 --> 00:02:02.359 The GMRS is allotted 30 channels, 16 main channels and 14 interstitial channels., 47 CFR 95.1763 Group, 462 MHz main; Count, 8; Spacing, 25 kHz; Power limit, 50 W (15 W fixed); Who may transmit, mobile, hand-held, repeater, base, fixed. 9 00:02:02.359 --> 00:02:19.479 Group, 462 MHz interstitial; Count, 7; Spacing, offset 12.5 kHz; Power limit, 5 W ERP; Who may transmit, mobile, hand-held, base. 10 00:02:19.479 --> 00:02:40.314 Group, 467 MHz main; Count, 8; Spacing, 25 kHz; Power limit, 50 W (15 W fixed); Who may transmit, mobile, hand-held, control, fixed, through a repeater only. 11 00:02:40.314 --> 00:03:05.530 Group, 467 MHz interstitial; Count, 7; Spacing, offset 12.5 kHz; Power limit, 0.5 W ERP; Who may transmit, hand-held only. The 462 MHz main channels run 462.5500 to 462.7250 in 25 kHz steps. 12 00:03:05.530 --> 00:03:23.446 The interstitials sit exactly between them: 462.5625, 462.5875, and so on. The 467 MHz groups repeat the same pattern 5.000 MHz higher. 13 00:03:23.446 --> 00:03:35.639 What each group is actually for. 462 MHz main, the eight channels that matter. Full 50 W, any station type, usable simplex or as a repeater output. 14 00:03:35.639 --> 00:03:48.495 If you are having a conversation on GMRS, you are almost certainly on one of these. 462 MHz interstitial, the shared low-power channels. Capped at 5 W ERP. 15 00:03:48.495 --> 00:04:01.849 These are the frequencies FRS radios use, so this is where you talk to a neighbour's bubble-pack radio. 467 MHz main, repeater inputs, not conversation channels. 16 00:04:01.849 --> 00:04:11.636 A mobile or hand-held station may transmit here only when working through a repeater, or for brief test transmissions. 17 00:04:11.636 --> 00:04:25.653 Setting a radio to simplex on 467.6000 is legal for a test and useless for a chat, because nobody is listening there. 467 MHz interstitial, half a watt, hand-helds only. 18 00:04:25.653 --> 00:04:37.846 These are the FRS "channels 8 to 14" that everyone wonders about. The limit is 0.5 W ERP for a reason: they were allotted for very short-range use. 19 00:04:37.846 --> 00:04:39.068 Bandwidth. 20 00:04:39.068 --> 00:05:11.689 The authorized bandwidth is 20 kHz for … the 462 MHz main channels, the 467 MHz main channels, and the 462 MHz interstitial channels, and 12.5 kHz for … the 467 MHz interstitial channels., 47 CFR 95.1773 In practice that maps onto the "wide/narrow" switch on a radio. 21 00:05:11.689 --> 00:05:36.246 The 467 MHz interstitials must be narrow; everything else may be wide. Peak deviation limits follow the same split: ±5 kHz on the wide channels, ±2.5 kHz on the 467 MHz interstitials (section 95.1775). 22 00:05:36.246 --> 00:05:56.173 The numbering, since your radio uses it. The 1 to 22 numbering is a manufacturer convention that predates the current rules. Roughly: Channels 1 to 7 are the 462 MHz interstitials, shared with FRS, 5 W. 23 00:05:56.173 --> 00:06:09.985 Channels 8 to 14 are the 467 MHz interstitials, 0.5 W, hand-held only. Channels 15 to 22 are the 462 MHz main channels, the full-power ones. 24 00:06:09.985 --> 00:06:27.347 Repeater channels, often labelled 15R to 22R or 23 to 30, pair a 467 MHz main input with the 462 MHz main output 5.000 MHz below. Treat these as a convenience, not as the rule. 25 00:06:27.347 --> 00:06:37.804 When two sources disagree about what "channel 19" means, the frequency settles it and the number does not. 26 00:06:37.804 --> 00:06:53.627 The habit to build. When you pick a channel, ask the three questions the rules ask: Which group is this frequency in? That gives you the power limit. What kind of station am I? 27 00:06:53.627 --> 00:07:12.146 Hand-held, mobile, base, fixed, repeater, the permitted set differs per group. Simplex or through a repeater? On 467 MHz main, only the second is permitted for mobile and hand-held stations. Check yourself. 28 00:07:12.146 --> 00:07:24.013 You are running a 40 W mobile. On which channels may you use that power? A radio is transmitting 5 W on 467.6625 MHz. What is wrong? 29 00:07:24.013 --> 00:07:32.644 Why is a conversation on 467.5500 MHz simplex a bad idea even where it is technically permitted? 30 00:07:38.644 --> 00:07:55.115 The 462 MHz main channels (and the 467 MHz main channels when working through a repeater), which permit 50 W. The interstitials cap you at 5 W ERP or 0.5 W ERP. 31 00:07:55.115 --> 00:08:10.248 467.6625 is a 467 MHz interstitial: 0.5 W ERP, hand-held units only. 5 W exceeds the limit by ten times. 467 MHz main channels are repeater inputs. 32 00:08:10.248 --> 00:08:31.764 Mobile and hand-held stations may transmit there only through a repeater or for brief tests, and nobody monitors them for conversation, so even where a fixed or control station might, the traffic goes nowhere.