Electronic And Postal Communications (Digital and other Broadcasting Networks) G.N. No. 418 (contd) In this network the inter-transmitter distance is 25 km in the case of portable and mobile receptions. It is therefore possible to use a value of 1/8 Tu (8k FFT) for the guard interval The same guard interval value might also be feasible for fixed reception, with its greater distance between transmitters of 40 km, since fixed roof-level reception is less sensitive to self-interference because of the directional properties of the receiving antenna. The parameters and the power budgets of this network given in Table 3 shall be used. III: Small service area SFN for urban environment (Table 4) (a) The geometry of the transmitter lattice of this network and the service area are identical to those of Small Service Area SFN, dense (b) This network applies to: fixed, outdoor/mobile and indoor reception, for both Band III and Bands IV/V. (c) This Network is intended for small service area SFN coverage in an urban environment. TABLE 4: PARAMETERS OF SMALL SERVICE AREA SFN FOR URBAN ENVIRONMENT RPC and RPC 1 RPC 2 RPC 3 reception type Fixed antenna Portable outdoor Portable indoor and mobile Type of network Open Open Open Hexagon Hexagon hexagon Number of transmitters 3 3 3 Geometry of transmitter lattice Triangle Triangle Triangle Distance d (km) 40 25 25 Service area diameter D (km) 53 33 33 Tx effective antenna height (m) 150 150 150 Non-directional Non-directional Non-directional Band III 24.1 32.5 40.1 Bands IV/V 31.8 44.9 52.2 Geometry of service area Tx antenna pattern e.r.p.* (dBW) The e.r.p. is given for 200 MHz in Band III and 650 MHz in Bands IV/V; for other frequencies (f in MHz) the frequency correction factor to be added is: 20 log10 (f/200 or f/650) for RPC 1 and 30 log10 (f/200 or f/650) for RPC 2 and RPC 3. * The e.r.p. values indicated in this table incorporate an additional power margin of 3 dB. IV: Semi-closed small service area SFN (Table 5) (a) This network is intended for cases in which increased implementation efforts regarding transmitter locations and antenna patterns are undertaken in order to reduce the outgoing interference of the network. 53