americas
the policeman on the ground, in some places he wants to use portable radios”, Lt-Col Cajueiro points out. “In Rio nowadays we understand this, and in our plans we intend (but it’s not possible, because we don’t have money for this!) to put our state on portable, mobile radios. We are studying where we can put the coverage and the extra sites, and maybe some mobile units to put coverage on the site during events.” Now DETEL is buying radio planning software so that,
Network traffic
statistics on a screen in the control room: the 31-site Teltronic Nebula IP system
supports some 300 active talkgroups and carries a daily
average traffic load of 50000 calls
Nonetheless, Lt-Col Cajueiro is enthusiastic about the
TETRA system, not least because of the high traffic capacity it provides and the dependable performance offered by an independently-managed system. “One of the best properties of TETRA is because when you are in trouble, or a crime area, or a big problem, you can operate with four people calling”, he says. “You have the best spectral efficiency. Many people can talk. It’s very important when you are in a very terrible situation and all the cellular systems are down. “When we have here Carnival and we have Reveillon
[New Year’s Eve], Fathers’ Day, Mothers’ Day, many people talk at the same time and we have the cellphones shutting down. Ten we understand that the spectral efficiency is very important. If you have spectral efficiency, like 4 × 1, like TETRA, it’s very important for us and for everybody.”
Frequency switch But another legacy of the 2007 network plan is that it was for vehicle radios only, not handportable coverage. “But
at the same time, its technicians can plan the best radio sites in readiness for one further evolution – this time imposed by Anatel, Brazil’s national telecoms regulator. Anatel plans to move the emergency services out of their 450MHz band by the end of 2018, to clear it for future rural broadband Internet services. DETEL will migrate to 380–400MHz, the frequencies used by public safety organizations in Europe. “For us that’s good, because we see that it’s not only in Brazil”, comments Lt-Col Cajueiro. “When you buy something that is international, you get a good price.” One factor which could help close the system’s performance
gap would be the new generation of higher-powered handportables, which are allowable in Brazil. “Maybe it’s better with 3 watts, because we have a network designed for analogue and we have problems with coverage”, he says. “If we can use more power, it’s better.... We will plan the future network for 3 watts, 1·8 watts or 1 watt. We understand the inverse correlation between power and the number of sites and the coverage.” Another facility he is looking for in new radios is ‘man
down’ alerting. “Some of the officers go into places which are quite dangerous, so this is very important”, he says.
Narcotics sweep For some operations, the force makes use of the full range of TETRA capabilities. Lt-Col Cajueiro describes a major multi-agency anti-narcotics operation which took place in Rio
Control and monitoring centre for the TETRA network at DETEL headquarters: at the desk is João Carlos Fernandes 26 TE TRA TODAY Issue 4 2011
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48