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ARP (Autoradiopuhelin, Car
Radio Phone in English) was the first
commercially operated public mobile phone
network in Finland. The technology is that of
zeroth generation (0G), since although it had
cells, moving between them was not seamless. The
network was proposed in 1968 and building began
in 1969. It was launched in 1971, and reached
100% geographic coverage in 1978 with 140 base
stations. ARP network was closed at the end of
the year 2000 along with NMT900.
ARP was a success and reached great popularity
(10800 users in the year 1977, 35000 in 1986),
but finally became too congested and was
gradually replaced by more modern NMT
technology. However ARP was for a long time the
only mobile phone network with 100% percent
coverage and it remained popular in many special
ARP operated on 150 MHz frequency (147.9 -
154.875 MHz). Transmission power ranged from 1
watt to 5 watts. It used half-duplex
transmission, meaning that receiving and
transmitting voice could not happen at the same
time. Being analog, it had no encryption and
calls could be listened to with scanners. It
started as a manually switched service, but was
fully automated in 1990 although by that time
the number of subscribers had dwindled down to
980 users. ARP did not support handover, so
calls would disconnect when moving to a new cell
area. Cell size was approximately 30 km.
ARP mobile terminals were extremely large for
the time and could only be fitted in cars'
trunks, with a handset near the driver's seat.
ARP was also expensive.