If you live in and around lake station,indiana here is some information for
you.lspd uses 2 repeaters(mr) 1 for fire and the other for police.the police
is 159.195.fire is 154.665.There is a local towing co that operates here on
157.500 and LSPD uses this for private comms between cars simplex they call
it SWITCH UP.the Merrillville indiana fbi office is often heard on 170.500
in the clear they have a trunked system but use this freq for local
surveillance its a repeater output.

Overview of Mobile Phone Systems

The large number of different mobile phone or cellphone systems that are
talked about today can be very confusing. Whilst not all are in use today,
some of the older systems have been superseded and some of the newer systems
have not all been rolled out yet, nevertheless many different names and
technologies are talked about. The table below gives a summary of the main
systems that have been used, are being used or are due for introduction.



Cellphone System


Generation


Channel Spacing


Access Method


Comments

AMPS


1G


30 kHz


FDMA


Advanced Mobile Phone System, this analogue system first developed and used
in the USA

NAMPS


1G


10 kHz


FDMA


Narrow band version of AMPS chiefly used in the USA and Israel based on a 10
kHz channel spacing.

TACS


1G


25 kHz


FDMA


Analogue system originally in the UK. Based around 900 MHz, this system
spread world wide. After the system was first introduced, further channels
were allocated to reduce congestion, in a standard known as Extended TACS or
ETACS

NMT


1G


12.5 kHz


FDMA


Nordic Mobile Telephone. This analogue system was the first system to be
widely used commercially being launched in 1979. It was used initially on
450 MHz and later at 900 MHz. It was used chiefly in Scandinavia but it was
adopted by up to 30 other countries including Oman.

NTT


1G


25 kHz


FDMA


Nippon Telegraph and Telephone. The system used in Japan, using a 900 MHz
frequency band, and 55 MHz transmit receive spacing. (A high capacity
version is known as HICAP).

C450


1G


20 kHz


FDMA


The system adopted in West Germany (East Germany was separate at this time).
It used a band in the region of 450 MHz along with a 10 MHz receive /
transmit spacing.

GSM


2G


200 kHz


TDMA


Originally called Groupe Speciale Mobile, the initials later stood for
Global System for Mobile communications. It was developed in Europe and
first introduced in 1991. The service is normally based around 900 MHz
although some 850 MHz allocations exist in the USA.

DCS 1800


2G


200 kHz


TDMA


1800 MHz derivation of GSM and is also known as GSM 1800.

PCS 1900


2G


200 kHz


TDMA


1900 MHz derivation of GSM, and is also known as GSM 1900.

TDMA


2G


30 kHz


TDMA


Although it was originally known as US Digital Cellular (USDC) and was
introduced in 1991. It is sometimes called North America Digital Cellular
and also known by its standard number IS-54 that was later updated to
standard IS136. It is a 2G digital system that was designed to operate
alongside the AMPS system.

PDC


2G


25 kHz


TDMA


Pacific or Personal Digital Cellular. The system found only in Japan where
it has gained very widespread use. It has many similarities with IS-54
although it uses a different speech coder and a 25 kHz bandwidth.

GPRS


2.5G


200 kHz


TDMA


General Packet Radio Service. A data service that can be layered onto GSM.
It uses packet switching instead of circuit switching to provide the
required performance. Data rates of up to 115 kbps attainable.

EDGE


2.5 / 3G


200 kHz


TDMA


Enhanced Data rates for GSM Evolution. The system uses a different form of
modulation (8PSK) and packet switching which is overlayed on top of GSM to
provide the enhanced performance. Systems using the EDGE system may also be
known as EGPRS systems.

CdmaOne


2G


1.25 MHz


CDMA


This is the brand name for the system with the standard reference IS95. It
was the first CDMA system to gain widespread use. The initial specification
for the system was IS95A, but its performance was later upgraded under IS95B
which the cdmaOne specification actually uses. Apart from voice it also
carries data at rates up to 14.4 kbps for IS95A and under IS95B data rates
of up to 115 kbps are supported.

CDMA2000 1X


2.5G


1.25 MHz


CDMA


This system supports both voice and data capabilities within a standard 1.25
MHz CDMA channel. CDMA2000 builds on cdmaOne to provide an evolution path to
3G. The system doubles the voice capacity of cdmaOne systems and also
supports high-speed data services. Peak data rates of 153 kbps are currently
achievable with figures of 307 kbps quoted for the future, and 614 kbps when
two channels are used.

CDMA2000 1xEV-DO


3G


1.25 MHz


CDMA


The EV-DO stands for Evolution Data Only. This is an evolution of CDMA 2000
that is designed for data only use and its specification is IS 856. It
provides peak data rate capability of over 2.45 Mbps on the forward or
downlink , i.e. from the base station to the user. The aim of the system is
to deliver a low cost per megabyte capability along with an always on
connection costed on the data downloaded rather than connection time.

CDMA2000 1xEV-DV


3G


1.25 MHz


CDMA


This stands for Evolution Data and Voice. It is an evolution of CDMA2000
that can simultaneously transmit voice and data. The peak data rate is 3.1
Mbps on the forward link. The reverse link is very similar to CDMA2000 and
is limited to 384 kbps.

UMTS


3G


5 MHz


CDMA / TDMA


Universal Mobile Telecommunications System. Uses Wideband CDMA (W-CDMA) with
one 5 MHz wide channel for both voice and data, providing data speeds up to
2 Mbps.

TD-SCDMA


3G


1.6 MHz


CDMA


Time Division Synchronous CDMA. A system developed in China to establish
their position on the cellular telecommunications arena. It uses the same
bands for transmit and receive, allowing different time slots for base
stations and mobiles to communicate. Unlike other 3G systems it uses only a
time division duplex (TDD) system.