parnass@RUTGERS.EDU> (01/15/90)
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BUYING A USED SCANNER
by Bob Parnass, AJ9S
Anybody with enough money can buy a brand new scanner,
but you can save lots of money if you get a good deal on
a used scanner. Hamfests are probably the best place to
find used radios, but you must be familiar with the
equipment. Hamfests are replete with older radios you
won't see in today's catalogs.
At last count, there were over 70 scanners and monitor
receivers of various brands in my collection. I purchase
most of my receivers at hamfests or horsetrade with other
radio hobbyists. This article describes a few of the FM
receivers in my collection, and is not meant to be com-
plete.
A Used Scanner May be a Broken Scanner
Getting a bargain is not without some risk. I have had
sellers look me square in the eye and tell me their radio
worked fine -- when it really didn't.
For this reason, you should have some recourse if the
radio you buy turns out to be defective.
If you can't fix the radio yourself, you can pay to have
the manufacturer or a service clinic repair it for you.
My personal experience with Uniden (the new manufacturer
of Bearcat and Regency scanners) has been disappointing.
Several people have been pleased with Electronic Repair
Center, in Franklin Park, IL, which repairs scanners for
a flat fee. Call them at (708)455-5105) to find out
their current rates.
Evolution of the Scanner
It helps to understand some scanner history before shop-
ping for a used scanner. You will likely see radios from
many vintages at a hamfest, and should to avoid buying
early units unless you are a scanner collector.
One of the earliest ancestors to the scanner was the con-
verter. Manufactured by Tompkins (Tuneaverter), Peter-
sen, Bearcat (Lil Tiger), Midland, and others, converters
were made to operate in conjunction with AM radios. Then
came wide band monitor receivers, in both tunable and
crystal control models, like the Radio Shack PRO-2B.
Truthfully, converters and tuneable FM receivers are
interesting but don't work well by today's standards.
While tuneable receivers were in vogue, solid state tech-
nologies supplanted tubes. Better performing, narrow
band crystal controlled units, like the Sonar FR-105,
followed. These units did not scan, rather channel
selection was accomplished using a simple rotary switch.
Sonar even made a 24 channel unit in which crystals were
held in a rotary "turret."
Perhaps the best known early scanners were the Regency
TMR and Bearcat units. The first Bearcat was rather
crude, providing no way to lock out channels from the
scan. The first scanners came in single band models,
followed by multiband models.
The first programmable (crystal-less) scanners were dif-
ficult to program. Users had to look up frequencies in a
code book and tediously program the information into the
scanner in binary form. Some models, like the Bearcat
BC-101, Radio Shack COMP 100, and Tennelec MCP-1, resem-
bled Altair or PDP-8 computers, with a row of 16 or so
toggle switches. Instead of toggle switches, the Regency
WHAMO-10 was programmed by breaking teeth from metal
combs. The SBE Optiscan (and its Sears clone) required
poking a series of holes in plastic cards which were then
inserted into a slot on the front panel.
More Modern Scanners
Both Bearcat and Regency, as well as Radio Shack offer
some good models. I would avoid the Bearcat 100, and
scanners made by AOR, JIL, Fox, Tennelec, and Robyn.
Scanner features often differ not only by model but by
manufacturer. For instance, most Radio Shack and Bearcat
programmables allow enable/disable of the delay function
on a per-channel basis. Older Regency units permit the
delay to be enabled/disabled only globally, that is, for
all the channels at one time.
Radio Shack scanners contain a reasonable number of
features, but the older models scan a bit slowly and have
a higher level of synthesizer noise. Most have too much
hysteresis in the operation of the squelch control, but
this can be fixed completely by replacing one resistor.
Good, detailed shop manuals are available for Radio Shack
units for $5 - $12.
In the name of cost cutting, some models have done away
with the concept of a "channel bank", i.e. the ability to
select/deselect a group of channels at a time. The bank
concept was a good one. It may be inconvenient to
operate a 30 channel scanner without banks (e.g. Regency
MX3000, HX1000) if you operate the way many scanner hob-
byists do.
A few years ago, Regency and Bearcat were purchased by
Uniden, a Japanese company.
My two favorite VHF/UHF receivers are the 300 channel
Radio Shack PRO-2004 (now replaced by the 400 channel
PRO-2005) and the ICOM R7000. The ICOM is more of a
"communications receiver" than a conventional scanner.
Other favorites include the Bearcat 300 and 760XLT,
Regency M400, and the Regency K500 (predates the M400),
all of which include a "service search" feature.
For portable use, I prefer the Uniden/Bearcat 200XLT,
although it's the Icom IC-2GAT scanning 138-174 MHz
walkie-talkie that goes wherever I do.
ICOM
R-7000: At about $1000, this is the Cadillac of VHF/UHF
receivers. 99 channel, multi mode coverage from 25-2000
MHz with a small gap at 1000-1025 MHz. Memory can be
expanded to 198 channels by adding simple switch to pin
19 of memory IC8. Tuning knob lets you tune through
parts of the spectrum much easier than using the SEARCH
mode on conventional scanners. Selectable USB/LSB allows
reception of new amplitude compandored sideband (ACSB)
stations. S-meter doubles as discriminator meter to aid
tuning. Useful search and store feature, reminiscent of
the the Bearcat 250, searches between 2 limits and
automatically stores new frequencies into channels 80-99.
Audio and control interface for tape recorder. Searches
and scans slowly but can be sped up to about 12 cps by
adding a resistor. Too big for permanent mobile use, but
too nice to leave alone in the car. If you don't want to
spend $1000, get a Radio Shack PRO-2004 instead for about
$400.
UNIDEN/Bearcat
800XLT: 40 channels in two banks. Covers 806-912 MHz,
as well as of vhf, uhf, and aircraft bands. Receives 10
meter fm and all of 6 meters, as well as federal portions
of vhf and uhf bands. Fewer birdies on vhf-lo band than
other scanners. Scans and searches very fast. Clean,
robust audio output. Extremely sensitive, but very prone
to overload by strong signals when connected to outdoor
antenna. Too much play (hysteresis) in squelch adjust-
ment - can be improved by changing one resistor. Posi-
tive terminal in memory backup battery holder installed
backwards in early units, allowing memory loss when
scanner unplugged from AC outlet. Tunes in increments of
12.5 KHz on 800 MHz band, whereas cellular telephones are
on 30 KHz channels.
BC350: 50 channels in 5 banks. Includes aircraft. Used
to be Bearcat's top of the line, overpriced scanner but
never very popular, now discontinued. Dual use keyboard
and display allowed 8 text characters to be associated
with each channel, a feature clumsily implemented, and
awkward to use. Units plagued with various hardware
problems including bad memory ICs and short life power
transformers. Firmware bugs without cures. The BC300 is
a much better scanner than the BC350, and at a lower
price.
BC300: 50 channel top of the line scanner. Service
Search feature contains 11 ROM banks of preprogrammed
channels. Switching power supply failure noted in early
units due to insufficient capacitance - component value
was changed in newer units. Schematics show at least 100
components changed between earliest and later units.
Preset squelch pot, mounted internally on circuit board,
misadjusted in new units - adjustment usually required
after burn-in period. Good sensitivity. Built in clock.
I leave it on 24 hours a day. This is a favorite.
BC20/20: 40 channels. Reasonable number of features.
Service Search for Marine and Aircraft. LED readout.
Good scanner, but tinny audio.
BC250: 50 channel discontinued model. Rich in features,
but lacks aircraft band and 144-146 MHz. Search and
Store feature extremely useful for finding federal fre-
quencies. Clock. High frequency of repair. Power
transistors not heat sinked adequately, causing heat dam-
age to surrounding components and circuit board. Failure
of Q204 on the feature board known to cause odd display
readings. Digital circuitry very sensitive to glitches
caused by static and AC line spikes. Avoid 1978 or ear-
lier vintage units. All BC250s use custom ICs (e.g.,
IC6, a divider chip, mfd. by Exar), which are now discon-
tinued, so factory service is no longer available from
Uniden.
BC260: Super heavy duty metal cabinetry and lit con-
trols, aimed at mobile use for firemen, police, etc. Few
frills, only 16 channels, no aircraft, but generous cov-
erage of federal bands omitted in the older Bearcat
scanners. Good sensitivity. Lots of audio. Good inter-
nal construction. Backlit keyboard allows operation in
the dark, but the keyboards on some units require high
pressure to operate. Brightness control for display and
keyboard, but multiplexor circuitry for vacuum fluores-
cent display produces audible whine which may be annoying
in a quiet room. Backlighting may fail in some units due
to poor contact on connector used to fasten light panel
to front circuit board. Method of connecting an external
speaker is awkward.
BC100: First programmable portable. Be prepared for at
least one repair in the first year. Early units, with
threaded antenna connector, have high frequency of
repair, particularly LCD readout, keyboard, and battery
holder. No battery backup. Poor case design in early
units caused battery to disconnect from radio, resetting
microprocessor and clearing memories. No priority chan-
nel or aircraft band. Some people swear by the BC100,
others swear at them.
BC100XLT: Excellent 100 channel portable with 10 prior-
ity channels. Unique feature tells whether a given fre-
quency has already been memorized. Generous coverage of
conventional bands, including commercial aircraft, but no
800 MHz. Decent leather-like case. Slide-on 550 mAH
NiCd battery pack.
BC101: First Bearcat synthesized unit. 16 channels, no
priority. Frequency programmed in binary by setting tog-
gle switches on front panel after looking up code in code
book. No frequency readout. Uses custom IC for CPU, now
discontinued, so factory authorized service is no longer
available. I have four of these units. Three work.
Bearcat_12: One of the last decent crystal controlled
scanners. 10 channels. Variable scan speed up to 20
ch/sec. Single delay on/off switch. Front mount speaker
sounds good. Manual contains schematic. Selectivity is
poorer than programmable models, like the 300, allowing
adjacent channel interference. No aircraft band cover-
age. Crystal positions must be arranged by band.
Regency
TMR_series: First generation crystal scanners. Come in
all varieties of band coverage. Models with both UHF and
VHF bands must use separate antennas for each band
(disadvantage in mobile installations, but can be over-
come by connecting two front ends via a capacitor). Easy
to crystal: Radio Shack crystals work well. TMRs usu-
ally $2 and up ad hamfests, often in poor condition.
Don't pay more than $50, even if mint. Front ends must
be tuned for selected portions within the bands for best
sensitivity. Wide IF selectivity troublesome in
urban/suburban areas. Primitive digital scanning circui-
try may become confused at times, but power off/on
restores sanity. Not all that bad a deal if cheap.
Replaced by Regency ACT units.
WHAMO-10: Regency's first synthesized scanner. Discon-
tinued long ago. Appearance more like a crystal scanner,
with a single LED per channel. User has to break off
teeth on a metal 'comb' for each channel according to a
code book. External frequency control unit DFS-5K
optional. UHF VCO reference oscillator drifts on some
units. Soldered sheet metal shields around some circui-
try make access to some components difficult for servic-
ing. Comb sockets prone to bad connections after
moderate use.
K500: Nice wood-like cabinet. Discontinued 40 channel
model with every feature Regency could dream of in one
scanner, except aircraft band. Idle tone bypass feature
for mobile phone stations works about 50% of the time.
Weather alert feature. Service Search in several banks.
Search and Store facility not implemented as well as
BC250, but better than none. Built in clock when radio
off or in manual mode. Can be programmed out of band.
Reasonable performance, but sensitivity could be better.
Spring contacts on membrane keyboard may need soldering
after prolonged use.
K100: Bare bones version of the K500. 10 channels, no
priority feature. Same wood-like cabinet and reasonable
performance as K500. Spring contacts on membrane key-
board may need soldering after prolonged use.
M400: 30 channel replacement for K500, but now discon-
tinued. Service Search, but no aircraft. Easily pro-
grammable out of band. Built in clock when radio off or
in manual mode. Backlit keyboard good for night viewing
and mobile use but generates RFI into nearby SW
receivers. A favorite.
MX3000: Discontinued 30 channel replacement for M400,
but basic features only. Nice lit keyboard, but may
cause RFI into nearby SW receivers. Easily programmable
out of band, but no aircraft. All 30 channels are in a
single bank, and lack of direct channel access make this
model more difficult to operate. Good first scanner.
M100: Discontinued 10 channel unit. Same as MX3000
except different color and fewer channels. Nicely lit
keyboard, but may cause RFI into nearby SW receivers.
HX1000: Good, fairly rugged, 30 channel handheld syn-
thesized unit. Generous out of band coverage but no AM
aircraft coverage. Built by Azden. Very sensitive on
UHF, but annoying audio hiss leaks through speaker when
squelched. Belt clip chintzy, but can be directly
replaced with better clip from Kenwood TR2600A. Like the
MX3000, all 30 channels are in a single bank, and lack of
direct channel access make this model more difficult to
operate. Low discount price makes this best choice for
programmable portable.
HX650/H604: 6 channel crystal portable. Likely made by
Sanyo. Same as Fannon and Bearcat Thin Scan units,
(except that Bearcat has 10.8 MHz IF frequency, and is
harder to get crystals for), but scans faster. Small
size and common crystals (available at Radio Shack), make
this 1st choice for bare bones portable scanner.
Radio Shack1
PRO2004: Top of the line, wide band scanner for 1987.
After a diode is cut, enjoy continuous coverage from
25-520 and 760-1300 MHz, AM, NBFM, and WBFM. Has 300
channels in 10 banks of 30, backed up by conventional 9
volt alkaline battery. Any channel can be designated the
priority channel. Scans and searches fast. Lots of well
designed features, like 10 pairs of search limits,
Lockout Review, default search increment and emission
mode. Sound Squelch allows skipping dead carriers during
search or scan. Metal cabinet, good internal construc-
tion and shielding, but no mobile mounting bracket or DC
power cord. Soft touch membrane keyboard. Good sensi-
tivity and selectivity. Very good radio.
PRO2005: Radio Shack's top of the line scanner for 1989
and today's scanner of choice. Essentially a size
reduced PRO-2004 with surface mount components and 400
channels. Some people think the small knobs, smaller
display, and plastic cabinet are a setback from the 2004.
The smaller size, real rubber keyboard, and vertical
front panel make it easer to use mobile, although there
is no mobile mounting bracket available and the keyboard
is not backlit. More sensitive than the PRO-2004 but 800
MHz signals leak through into the commercial aero band.
PRO34: Portable scanner with 200 channels and 800 MHz
coverage. Ten "monitor" channels. Operates from AA
cells. Slow scanning, low audio output, and chintzy
plastic case detract from an otherwise good performance.
No decent leather case available from Radio Shack. If
you need a portable with 800 MHz, get a Bearcat 200XLT.
If you can't get a 200XLT, get a PRO-34.
PRO2021: Base/mobile scanner. 200 channels in 10 banks,
LCD display and raised rubber keys. Lots of memory but
scans too slowly and lacks 800 MHz. Ten "monitor" chan-
nels. Radio Shack seemed to have an overstock of 2021s
as they were on sale for such a long time. Close out
price dipped to about $200, which made it a nice scanner
for beginners.
PRO2001: Early, discontinued single bank 16 channel pro-
grammable. Reasonable coverage of the 3 traditional
bands, minus aircraft band. LED digital display as well
as an LED per channel. Mechanical lockout switch for
each channel. Delay is either on or off for all channels
at a time. High synthesizer noise level. Troublesome
plated through holes on digital board in some units
renders radio virtually unfixable. Could never get mine
to work more than a few days in a row; always another bad
connection. Some owners have no trouble.
PRO52: Discontinued 8 channel VHF-Lo/Hi base unit. No
UHF band or provision for mobile operation. Good little
scanner despite limited frequency coverage and Spartan
lack of frills. Front mounted, vertical speaker always a
win.
PRO2003: Radio Shack's 1986 top of line. 50 channels +
10 FM commercial broadcast band channels. Includes air-
craft. Good frequency coverage and functionality, but at
a high price. Poor human engineering: difficult to read
keyboard makes the PRO2003 hard to operate unless in a
well lit room. Keyboard label coloring improved on newer
units. Rather slow scan rate and high price. Although
there are provisions for 12VDC operation, the cabinet
shape and lack of mounting bracket makes mobile operation
impractical. Scan rate only 8 channels/sec vs. 15/sec in
Regency and Bearcat. Causes RFI: Plastic case permits
scanner to radiate signals into nearby receivers.
PRO30: 16 channel programmable portable with aircraft
band. Good frequency coverage. Extra controls on top
allow control of SCAN, MANUAL, and PRIORITY functions
while worn on belt. Good belt clip. Low audio output.
Plastic case prone to break at BNC antenna connector
under severe use, vs. metal frame in Regency HX1000.
High price, no discounts or sales yet. I had 6 or 7
PRO30s, having to return them several times during the 1
year warranty, although other owners have had little or
no trouble. Troubles included oscillation in IF stage,
no UHF band reception, case broken around base of antenna
connector, etc.
PRO24: Only 4 channels in this crystal controlled port-
able. Covers the three basic bands, but no aircraft.
Easy to obtain batteries and crystals. Characteristic
Radio Shack squelch problem, fixable by changing one
resistor. All-plastic case larger than Bearcat Thin Scan
and clones.
Craig2
4530: Discontinued Japanese 10 channel crystal con-
trolled 3 band unit. Also available under Plectron name
but in different cabinet. No aircraft band. Deluxe
features like priority, trimmer capacitors for netting
each channel, front panel speaker, and rugged metal
cabinet make this unit a winner. Channel lockout slide
switches have finite life. Replacing burned out incan-
descent channel lamps not fun. Grab a 4530 if you find
one in good condition.
Tennelec
Manufactured the first synthesized scanners. Company
went out of business several years ago. Schematics and
parts difficult to obtain. Radios reputed to be poor
performers. Got my MS-2 and MCP-1 basket cases for free
and sometimes regret taking them. Not worth fixing
unless you have access to DTL/RTL chips and circuit
diagrams.
__________
1. Radio Shack scanners are manufactured by General
Research Electronics of Tokyo (GRE).
2. Craig is a division of Pioneer.
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Bob Parnass, AJ9S - AT&T Bell Laboratories - att!ihuxz!parnass (708)979-5414