25/P25 radios are implemented with mobile TX at 821 to 824 MHz (immediately adjacent to the US 850 cellular mobile transmit band between 824 and 849 MHz) and mobile RX at 866 to 869 MHz (immediately adjacent to the US 850 mobile receive at 869 to 894 MHz). However, Release 9 of the 3GPP specifications proposes three extensions/variations to the US 850 band including adding 10 MHz at the lower end of the present Band 5 allocation that includes all of the legacy P25 800 MHz channels and some of the proposed new channels. P25 radios and iDEN radios are now coming to market capable of supporting the frequency bands shown in Table 16.7. This extends P25 and iDEN into channels previously used and still used for analogue two-way radio. The table also shows the impact of the proposed extension of the US 850 cellular band. As stated earlier iDEN radios have 25-kHz channel spacing with a transmit power of up to 1 watt and a six-slot QPSK modulated TDMA physical layer. P25 radios can have 12.5, 20 or 25 kHz channel spacing and an output power of between one and three watts (also QPSK modulated). In-car mobiles can have an output power anywhere between 10 and 35 watts. Base stations can be up to 100 watts. This is serious radio, optimised for rural coverage and deep urban inbuilding penetration. Satellite Networks Table 16.7 US 800-MHz public safety - old and new band plan 806 to 810 MOB/UE TX Conventional PMR New Project 25 810 to 816 Trunked PMR TX or iDEN 816 to 821 iDEN/wIDEN 806 to 824 MHz 821 to 824 APCO 25 18 MHz or 8 MHz with no US 850 overlap 824 to 849 US 850 cellular Proposed extension down to 814 MHz 851 to 855 MOB/UE RX Conventional PMR New Project 25 855 to 861 Trunked PMR RX or iDEN 861 to 866 iDEN/wIDEN 851 to 869 MHz 866 to 869 APCO 25 18 MHz or 8 MHz with no US 850 overlap 869 to 894 US 850 cellular Proposed extension down to 859 MHz 896 to 902 Trunked PMR iDEN SMR 896 to 902 MHz 934 to 940 Trunked PMR iDEN SMR 934 to 940 MHz Multiband versions of P25 radios also have to be capable of working at VHF between