X hits on this document





23 / 24

450-470 MHz band alignment

Step 3

As explained in Step 2, there are a number of channels within the paired PMR blocks that, as well as being duplex channels, also exist as independent single-frequency channels. The next step of the move starts to gather these single-frequency channels into channels between 440 and 450 MHz, in line with the CEPT Recommendation. These are largely on-site services, which can conveniently be considered as mobile transmit since, even though there may be base stations, these will be of similar power to handheld radios. So the single-frequency block is placed below 450 MHz in the single-frequency band.

Step 4

Scanning Telemetry (principally used by the utilities for remote acquisition of data for command and control purposes) occupies two blocks, each of 1 MHz. One of these blocks is used by central stations that transmit to a number of outstations and collect data. The other is used for transmissions from the outstations. The scanner can be considered a base station and the outstations can be considered mobiles, even though they are fixed in location and can thus use directional antennas. This phase moves the scanner transmitters to 461.5-462.5 MHz, vacated by PMR mobile transmitters in a previous phase. The outstation transmitters move to 451.5-452.5 MHz, which is vacant since this is ex-Emergency Services spectrum.

Step 5

This rationalises the residual Emergency Services spectrum – which is currently made up of several small blocks in various positions in the band – into two blocks with the correct spacing.

Step 6

There are 26 channels used at airports for controlling the movement of vehicles in close proximity to aircraft. These are basically PMR systems, but require Civil Aviation Authority (CAA) approval for assignment. These channels are moved in this phase to holes at 467 MHz and 457 MHz, both of which were vacated by Emergency Services in the previous phase

Step 7

Programme Making and Special Events has a number of blocks distributed in the band. At present these are concentrated towards the top of the band, but (as explained in Annex B) this can be problematical in areas where television channel 21 is used. Major news or sporting events generate a large requirement for separate, co-located on-site systems; this requires careful frequency planning to avoid technical problems. To meet this requirement, it is best to provide several small blocks distributed throughout the band rather than one large contiguous block. This phase creates a pair of 500 kHz blocks in the centre of the band, at approximately 455 and 465 MHz. At present, the bottom end of the lower block contains some channels used for railways’ track-to-train communications systems (allowing one-person operation of trains). In time, this system will migrate to a new digital system in a different band, so these channels will become clear.

Step 8

This moves the single-frequency channels within the other paired PMR block at 453-454 MHz and 459.5-460.5 MHz into channels between 440 and 450 MHz.

Step 9

This moves the duplex channels in the second PMR pair to be appended to the existing aligned duplex channels. This creates a large contiguous paired PMR block.

Step 10

We now complete the single-frequency block by moving the single-frequency channels from 461 MHz to channels between 440 and 450 MHz in the new single-frequency block.

Step 11

This continues the redistribution of Programme Making and Special Events spectrum by creating a paired block at the bottom of the band, separated by approximately 5 MHz from the block created previously.

Step 12

This completes the process by rationalising the remaining Programme Making and Special Events spectrum, through extending two existing blocks at just above 457 and 467 MHz, either side of the already correctly positioned Maritime On-Board channels.

The 12 steps of the process are illustrated in the chart accompanying this document. Throughout the process it is not possible to give exact frequency ranges for the new blocks of spectrum, since the extent to which yields will be made as a result of the introduction of better spectrum planning techniques is not yet known.

Page 23 of 24

Document info
Document views88
Page views88
Page last viewedMon Jan 23 17:28:52 UTC 2017