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Hackers Underworld 2: Forbidden Knowledge
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MOD_21.TXT
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1990-01-24
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431 lines
THE RADIO SHACK PRO-2005 PROGRAMMABLE SCANNER
by Bob Parnass, AJ9S
Manufactured in Japan by General Research Electronics,
the Radio Shack PRO-2005 is a 400 channel, wide coverage
scanner radio, incorporating NBFM, WBFM, and AM modes.
It is the successor to the PRO-2004, the super scanner
which put Radio Shack out in front of its competition in
the base station scanner market.
The 2005 is basically a 400 channel PRO-2004, built using
surface mount components, and housed in a smaller pack-
age.
Frequency Coverage
Radio Shack's last minute decision to remove cellular
telephone frequency coverage from the PRO-2004 caused a 7
week delay in its introduction. The PRO-2005 appeared in
the stores promptly on the heels of the 2004 closeout
sale. Both the PRO-2004 and PRO-2005 cover 25-520 and
760-1300 MHz, except for 2 gaps in the cellular telephone
bands. The two gaps in the 800 MHz range can be restored
in either scanner by clipping a diode.
A matrix of diodes, attached to the microprocessor's
input port, is often used to configure radios for sale in
different markets. The diode matrix on new the PRO-2005
is located on the vertical circuit board just behind the
front panel. There are 2 diodes present, and holes
drilled for 2 more.
Lots of Memory
The PRO-2005 has the usual features that scanner buffs
have come to expect: individual channel lockouts,
selectable rescan delay, an external speaker jack, etc.
But, the 400 channel capacity of the PRO-2005 sets
another an industry record, just as the 300 channel PRO-
2004 did! Casual scanner users may scoff at the useful-
ness of having so many channels, but seasoned monitorists
can have those channels filled up in no time flat, espe-
cially with frequencies in the vast 225-400 MHz military
air band, and other federal government allocations.
With so many channels to program, one dreads the thought
of a power failure, which could clear memory in a hurry.
Not to worry, the PRO-2005 memory is backed up by a
- 2 -
conventional 9 volt alkaline battery (not supplied). The
400 channels are divided into 10 banks of 40 channels
each, and one can select or deselect any channel bank
from the scan list. Individual channels can be locked
out in the customary way, but the PRO-2005 maintains the
handy feature introduced in the PRO-2004, a LOCKOUT
REVIEW. Successive depressions of this key step through
the locked out channels.
Scanners worth their keep have a priority feature, with
channel 1 usually designated the priority channel. The
PRO-2005 is more flexible; any of the 400 channels may be
designated the priority channel. When the PRIORITY key
is depressed, that channel will be sampled every 2
seconds, and the radio will stay there if a signal is
heard.
The PRO-2005 has two scan speeds, approximately 8 and 16
channels/second, although one would probably use the fas-
ter speed in most instances. This is the same speed as
the stock PRO-2004, as measured by your reviewer. A
diode could be added to the PRO-2004 diode matrix to
speed up the scan and search rates by 25%. The provision
for extra diodes in the diode matrix makes one hopeful
that the same speedup trick can be applied to the newer
PRO-2005.
When programming a channel, the PRO-2005 firmware sets
the mode automatically, based on its idea of what mode is
most prevalent on that frequency. This feature saves
extra keystrokes, and makes one appreciate the thought
that went into the design of this radio. The default
mode can be overridden easily, if need be, like to listen
to a NBFM satellite in the 225-400 MHz range, which is
mainly populated with AM signals.
Searching
The SEARCH facility found on most programmable scanners
allows the entry of a pair of frequencies, then by press-
ing a key, the radio searches frequencies between those
limits. The PRO-2005 allows for 10 pairs of limits!
These pairs of limits are stored in their own memory, and
don't use up any of the conventional 400 memory channels.
One can set up several search pairs, for instance:
- 46.610-46.970 MHz: cordless telephones
- 144-148 MHz: the 2 meter ham band
- 3 -
- 30.01-30.56, 32-33, 36-37 MHz: US Govt
Another unique feature is the MONITOR key, which stops
the search and stores the frequency in one of ten special
monitor memories. These memories are separate from the
400 main memory channels. The search can be restarted
from where it left off by striking the up or down arrow
key.
The user can select the search direction (up or down),
and step size of 5, 12.5, or 50 kHz, although the PRO-
2005 is intelligent enough to select a default step size
based on the frequencies being searched. As on the PRO-
2004, there is a hidden step size of 30 kHz, but
apparently this step size was disabled when the cellular
telephone frequency coverage was removed.
The selected parameters are displayed on the LCD panel,
smaller than the panel in the PRO-2004. Search speed is
switchable between slow and fast, with fast search being
about 14 increments/second (versus 12 for the
Uniden/Bearcat 800XLT). For a 12.5 kHz increment, this
translates to 11.2 MHz/minute (versus 9.6 MHz/minute for
the 800XLT).
The DIRECT key allows one to start searching up or down
from whatever frequency is on the display. Let's say the
scanner is in MANUAL mode, and set at channel 26, which
contains 460.100 MHz. Striking the DIRECT then UP-ARROW
keys starts the PRO-2005 searching upwards from 460.100.
This is a nice feature.
The PRO-2005 contains a "window detector" circuit, which
is called into play during a SEARCH operation. This cir-
cuit tries to detect when the radio is tuned close to the
center frequency of a station, and prevents the search
from halting prematurely, off to the side of the signal.
The AFC (automatic frequency control) circuit of the
Bearcat 800XLT often causes a search of 850 MHz signals
to halt prematurely. Even though the signal sounds on
frequency, the display reads the wrong frequency. Nei-
ther the PRO-2004 nor the PRO-2005 have this problem.
The PRO-2005 includes a SOUND SQUELCH, resembling the VSC
circuit on the Icom R-7000, which may be used during scan
or search operations. With the the sound squelch
enabled, signified by a red lamp above the pushbutton,
the scanner will skip over unmodulated signals. This is
handy for skipping over "birdies", or link signals with a
constant carrier.
- 4 -
The manual warns that the sound squelch may be fooled by
signals with low modulation, and skip over them. The
PRO-2005 SOUND SQUELCH tries to detect the presence or
absence of modulation (not human speech), so unfor-
tunately, it thinks that noisy dead carriers, digital
data signals, and paging tones are worth monitoring and
will stop the scanner to listen to them.
Taping Facility
A tape recorder can be connected to the TAPE phono jack
on the rear panel, which provides 600 mV of audio at a
10,000 ohm impedance. An audio filtering circuit rolls
off the high frequency components befo