Considering the upsurge in recent 11 meter activity (including DX from the UK), I figured I would write a quick bit of information on the UK's Community Audio Distribution System (CADS) and Ireland's Wireless Public Address System (WPAS).
CADS: Ofcom (the UK's communications regulatory agency) allows for broadcasting of religious and community events using low-power transmitters on the 27 MHz (CB) or 11-meter band. As of March 2007, no license is required in the UK for operation of the CADS system. CADS uses the "CB 27/81" (commonly known as UK FM CB) allocation which consists of 40 channels spaced 10 kHz apart starting at 27.60125 MHz for channel 1 and ending at 27.99125 MHz for channel 40. FM modulation is the only mode allowed with 4 watts maximum power. CADS is commonly used to transmit church services to local residents using regular CB equipment and vertical antennas. Truly continuous (i.e. leaving the transmitter on 24/7) transmission is not permitted (although sometimes practiced nonetheless).
WPAS: ComReg (Ireland's communications regulatory agency) allows for a very similar system to CADS. WPAS transmitters are only allowed to transmit real-time audio from public events and is only available for non-commercial use. ComReg requires registration and licensing of transmitters to be used in the WPAS. It appears, however, that this is rarely practiced or enforced. WPAS differs from CADS in two important ways. First, CADS allows for either AM or FM modulation (user's choice - mode must be indicated on license application). Second, CADS' frequency allocation is actually two sets of 40 "interleaved" channels, spaced at 10 kHz. Channel Block LW consists of channels LW01 through LW40. These correspond with the UK FM (and also CADS) channels 1 through 40 respectively. Channel Block UW consists of channels UW01 through UW40. Channel UW01 is 27.605 MHz and channel UW40 is 27.995 MHz. Straight 10 kHz spacing up through the channels.
*Legal* 27 MHz Church Frequency List: - As you can see there is some really tight spacing between these channels. Especially the WPAS channels.
27.60125 CADS 01 FM - WPAS LW01 AM/FM
27.60500 WPAS UW01 AM/FM
27.61125 CADS 02 FM - WPAS LW02 AM/FM
27.61500 WPAS UW02 AM/FM
27.62125 CADS 03 FM - WPAS LW03 AM/FM
27.62500 WPAS UW03 AM/FM
27.63125 CADS 04 FM - WPAS LW04 AM/FM
27.63500 WPAS UW04 AM/FM
27.64125 CADS 05 FM - WPAS LW05 AM/FM
27.64500 WPAS UW05 AM/FM
27.65125 CADS 06 FM - WPAS LW06 AM/FM
27.65500 WPAS UW06 AM/FM
27.66125 CADS 07 FM - WPAS LW07 AM/FM
27.66500 WPAS UW07 AM/FM
27.67125 CADS 08 FM - WPAS LW08 AM/FM
27.67500 WPAS UW08 AM/FM
27.68125 CADS 09 FM - WPAS LW09 AM/FM
27.68500 WPAS UW09 AM/FM
27.69125 CADS 10 FM - WPAS LW10 AM/FM
27.69500 WPAS UW10 AM/FM
27.70125 CADS 11 FM - WPAS LW11 AM/FM
27.70500 WPAS UW11 AM/FM
27.71125 CADS 12 FM - WPAS LW12 AM/FM
27.71500 WPAS UW12 AM/FM
27.72125 CADS 13 FM - WPAS LW13 AM/FM
27.72500 WPAS UW13 AM/FM
27.73125 CADS 14 FM - WPAS LW14 AM/FM
27.73500 WPAS UW14 AM/FM
27.74125 CADS 15 FM - WPAS LW15 AM/FM
27.74500 WPAS UW15 AM/FM
27.75125 CADS 16 FM - WPAS LW16 AM/FM
27.75500 WPAS UW16 AM/FM
27.76125 CADS 17 FM - WPAS LW17 AM/FM
27.76500 WPAS UW17 AM/FM
27.77125 CADS 18 FM - WPAS LW18 AM/FM
27.77500 WPAS UW18 AM/FM
27.78125 CADS 19 FM - WPAS LW19 AM/FM
27.78500 WPAS UW19 AM/FM
27.79125 CADS 20 FM - WPAS LW20 AM/FM
27.79500 WPAS UW20 AM/FM
27.80125 CADS 21 FM - WPAS LW21 AM/FM
27.80500 WPAS UW21 AM/FM
27.81125 CADS 22 FM - WPAS LW22 AM/FM
27.81500 WPAS UW22 AM/FM
27.82125 CADS 23 FM - WPAS LW23 AM/FM
27.82500 WPAS UW23 AM/FM
27.83125 CADS 24 FM - WPAS LW24 AM/FM
27.83500 WPAS UW24 AM/FM
27.84125 CADS 25 FM - WPAS LW25 AM/FM
27.84500 WPAS UW25 AM/FM
27.85125 CADS 26 FM - WPAS LW26 AM/FM
27.85500 WPAS UW26 AM/FM
27.86125 CADS 27 FM - WPAS LW27 AM/FM
27.86500 WPAS UW27 AM/FM
27.87125 CADS 28 FM - WPAS LW28 AM/FM
27.87500 WPAS UW28 AM/FM
27.88125 CADS 29 FM - WPAS LW29 AM/FM
27.88500 WPAS UW29 AM/FM
27.89125 CADS 30 FM - WPAS LW30 AM/FM
27.89500 WPAS UW30 AM/FM
27.90125 CADS 31 FM - WPAS LW31 AM/FM
27.90500 WPAS UW31 AM/FM
27.91125 CADS 32 FM - WPAS LW32 AM/FM
27.91500 WPAS UW32 AM/FM
27.92125 CADS 33 FM - WPAS LW33 AM/FM
27.92500 WPAS UW33 AM/FM
27.93125 CADS 34 FM - WPAS LW34 AM/FM
27.93500 WPAS UW34 AM/FM
27.94125 CADS 35 FM - WPAS LW35 AM/FM
27.94500 WPAS UW35 AM/FM
27.95125 CADS 36 FM - WPAS LW36 AM/FM
27.95500 WPAS UW36 AM/FM
27.96125 CADS 37 FM - WPAS LW37 AM/FM
27.96500 WPAS UW37 AM/FM
27.97125 CADS 38 FM - WPAS LW38 AM/FM
27.97500 WPAS UW38 AM/FM
27.98125 CADS 39 FM - WPAS LW39 AM/FM
27.98500 WPAS UW39 AM/FM
27.99125 CADS 40 FM - WPAS LW40 AM/FM
27.99500 WPAS UW40 AM/FM