GRE PSR-500, Руководство пользователя

Страница: 11 / 138

personify the hobby at the time, and it was quite an experience to
see the light show from multiple radios in a well-equipped
scanner shack
Early microprocessor controlled scanners eliminated the need for
crystals and increased the number of channels that could be
scanned. Without keypads and numeric or alphanumeric displays
these early microprocessor controlled radios still relied on the
traditional row of lights to show scanning activity. A row of
switches was used to enter binary code to store individual
frequencies. In some later models a punch card or metal comb
was used to load the binary code.
The true predecessors of today ʼ s modern scanning receivers are
those first radios to use a numeric keypad to store frequency
information and control the radio, and numeric LCDs to show the
programmed information and display the status of the radio. The
row of lights was replaced with a row of zeroes or other display
elements in the LCD to show scanning activity.
As it became possible to increase the memory capacity of these
microprocessor controlled scanners, designers started looking
for ways to organize this expanded memory to make operation
easier for users. This lead to the typical bank/channel memory
organization that is still used in many scanning receivers today.
This design works well when scanning conventional, non-trunked
frequencies.
Trunking presented new challenges for designers. Early trunking
scanner designs operated in trunking or conventional mode, but
not both at the same time. Because programming for trunked
systems includes many parameters not normally used in
conventional radio scanning, it was necessary to design a
completely separate user interface for entering trunking
parameters and scanning trunked systems. Soon after the first
early models were released, new “multi-scanning” receivers
appeared that allowed users to scan different combinations of
trunked systems or conventional channels simultaneously.
Trunking scanners soon earned a reputation for being complex
and difficult to program. Even experienced and expert users
were frustrated when confronted with the challenges of
programming and operating a trunked scanning receiver. Part of
the problem with trunking scanners was the way that trunking
functionality was added to the radio. Until recently, trunking
functionality was forced into the traditional bank/channel scanner
design. This confused and frustrated users, who had to learn two
PSR-500 User Manual Page 11