DAB Aerials

1. Band 3 (174-240MHz) Receivers will generally work down to -90dBm RF signal level. We suggest a margin of 10db, ie -80dBm or above for real comfort. Signal strength meters should be designed for the 1.5MHz bandwidth of DAB signals.

1a. The minimum Field Strength for service, at 1.5m above ground level, for receiver operation is considered to be 37dBuV/m. Networks are planned to give 47dBuV/m to account for localised variations.

2. DAB coverage areas are generally defined for in-street use. Roof mounted antennas will generally give good results up to and slightly beyond the predicted coverage.

3. All external DAB antennas must be VERTICALLY polarised. Simple omni-directional, dipole or collinear designs are generally preferred and should be the first choice. Directional Yagi antennas should be avoided other than in exceptional circumstances, as they can actually reduce performance.

4. Signal indicators on receivers are extremely misleading and they should be treated with great caution. They often indicated Bit Error Rate which itself is misleading or alternatively indicate signal strength of more than one DAB transmission, which is also very misleading.