Hearing what almost sound like telemetry signals on 27255 kHz this morning. Data bursts roughly 10 kHz wide...varies from every 2 seconds to a 10-12 second wait between bursts. Nothing else on frequency this morning, and the 11 meter band is relatively quiet. Just the usual 27185 (Channel 19) and 27355 (Channel 35) AM voice traffic.
I've heard POCSAG mode paging on 27.255 (CB channel 23) before and I know it is used for various on-site telemetry system in addition to R/C purposes (with 26995, 27045, 27095, 27145 and 27195). I have also logged non-stop tone signals on 27255 (although this very well could have been CBers playing around).
FCC rules permit up to 25 watts carrier power on 27.255 MHz for telemetry, paging, etc...that means 100 watts PEP power in AM mode
Update:
Reference FCC Rules:47 CFR 95.207 (FCC Rules Part 95 Section 207)
47 CFR 95.210 (FCC Rules Part 95 Section 210)
47 CFR 95.207 § 95.207 (R/C Rule 7) On what channels may I operate? (1) The following channels may be used to operate any kind of device (any object or apparatus, except an R/C transmitter), including a model aircraft device (any small imitation of an aircraft) or a model surface craft device (any small imitation of a boat, car or vehicle for carrying people or objects, except aircraft): 26.995, 27.045, 27.095, 27.145, 27.195 and 27.255 MHz.
47 CFR 95.207b § 95.207b (b) You must share the channels with other R/C stations. You must cooperate in the selection and use of the channels. You must share the Channel 27.255 MHz with stations in other radio services. There is no protection from interference on any of these channels.
47 CFR 95.207f § 95.207f (f) Stations in the 26-27 MHz range are not afforded any protection from interference caused by the operation of industrial, scientific of medical devices. Such stations also operate on a shared basis with other stations in the Personal Radio Services.
47 CFR 95.210 § 95.210 (R/C Rule 10) How much power may I use?47 CFR 95.210a § 95.210a (a) Your R/C station transmitter power output must not exceed the following value under any conditions:
Channel: 27.255 MHz Transmitter power (carrier power) (watts) 25
Channel: 26.995-27.195 MHz Transmitter power (carrier power) (watts) 4
Channel: 72-76 MHz Transmitter power (carrier power) (watts) 0.75
Since the FCC regulations under 95.210 specifically state transmitter
carrier power instead of peak envelope power, just like how the CB rules specify 4 watts maximum
carrier power for 26.965-27.405 MHz, that means that peak envelope power (PEP) for 27.255 can legally be up 100 watts (just like PEP on the CB channels can legally be up to 16 watts).
This also means that you can transmit up to 4 watts carrier / 16 watts PEP on 26.995 MHz, 27.045 MHz, 27.095 MHz, 27.145 MHz and 27.195 MHz for R/C purposes. Interestingly enough, 27.255 MHz is included in the R/C services for telecommand and telemetry, which one could infer that the other 5 frequencies could be used for this purpose as well (with less maximum transmitter power than allowed on 27.255 MHz). 27.255 is also the only one out of the six available 26-27 MHz channels that is shared with a legal CB channel.
FWIW, this also translates to a maximum power (PEP) of 3 watts (0.75 watts carrier x4) on the 72.01 MHz to 72.99 MHz and 75.41-75.99 MHz bands.