Bearcat Thin Scan Portable Scanner
While portable scanners have been around for some time, few have been
classed as true pocketable receivers. Bearcat's new Thin Scan is indeed
pocketable. Measuring only
about an inch thick and 2 1/4 inches wide, the scanner will fit in most
pockets with ease. Its 5 1/2-inch height poses no particular problems,
either. Nor does its 7 ounce weight.
The Thin Scan comes equipped with two
antennas. More than likely, the user will want to sport the "rubber ducky"
flexible antenna. A thin, insulated wire antenna is also provided that
may be used where unobtrusive reception is necessary. The wire antenna
may be routed anywhere that is convenient, with some reduc- tion in
reception range to be expected because of body capacity.
of the little scanner is handsome and conservative. The black case
is accented by a metallic-brown front bezel. A row of LED's signal the
channel scanning sequence on the front panel.
Functionally, the Thin Scan
(model two-four) is a four channel, two band (high and low VHF) crystal
controlled receiver. It is powered by four AAA cells, with a
nickel-cadmium charging provision at a side jack. An external power supply jack
is also provided for long-term operation from an AC source. Current
drain is nominally 20 mA squelched, 50 mA at full output.
Thumbwheel controls for volume and squelch are conveniently located on the side,
making adjustment quite natural. For privacy, an external earphone may
be plugged into an audio jack on the top of the receiver.
Channels are individually controlled by lockout switches. Manual pushbutton stepping
from channel to channel is also allowed by a fingertip control. The
internal 2-inch speaker is driven with up to 100 milliwatts of audio,
adequate for any personal monitoring. Audio remains quite intelligible
(10% total harmonic distortion) even at high output levels.
Crystals may be mixed between high- and low-band in any proportion. An automatic
socket switching arrangement accommodates the pleasure of the user. The
Thin Scan is a double conversion superheterodyne, with IF's of 10.8
MHz and 455 kHz. The crystal formula for low band selection is:
receive frequency + 10.8 MHz = crystal frequency.
At high band, the formula becomes:
( receive frequency - 10.8 MHz ) / 3
Crystals may be ordered as type number A-135 from Electra at $5
Factory alignment is optimized for midband in the 33-47
and 152-164 MHz ranges. Mid-band sensitivity is advertised as
typically 0.6 microvolt. In fact, our lab measurements confirmed this
approximate sensitivity for 20-dB quieting. Sensitivity decreases
to about one microvolt at the ends of the alignment ranges. Although
not quite so sensitive as more elaborate and expensive scanners,
it is perfectly adequate for the local use for which such a device is
Scanning rate is 8 channels-per-second. Squelch
sensitivity is near 0.5 microvolt, adjustable to 2 microvolts by
the squelch control. Spurious signals are rejected some 50 dB, with
images down 35 dB. Modulation acceptance is designed for narrowband ±5
The internal circuitry is very straightforward, using recently
developed IC's for communications applications. A Motorola MC3357 FM
IF IC drives an LM386N audio amplifier. All RF and oscillator stages
are discrete transistors. Adjacent channel selectivity is controlled
by ceramic filters.
The circuitry is designed so that the oscillator
will not drop out until battery voltage has been depleted to about 4 1/2
volts. As with all battery operated equipment, it is a good idea to check
the scanner briefly for operation after long periods of inactivity to make
sure that the batteries are still functional. This will help protect
against possible battery leakage damage. Better yet, remove the four
AAA cells until the unit is to be used again.
We found the Thin Scan to
be attractive, reliable, and quality built. It is manufactured offshore
for Electra by a prominent electronics firm. The model two-four Thin
Scan has a suggested retail price of $149.95. Available from Electra,
300 East County Line Road, Cumberland, IN 46229.