💾 Archived View for gemini.spam.works › mirrors › textfiles › hamradio › usedsc.ham captured on 2020-10-31 at 18:22:07.
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By popular demand, here is an article which appeared in 8/88
Monitoring Times. Since it is now a few years old, I haven't
updated it with info on the latest model scanners.
PS - MT used the title, "Confessions of a Scanner Collector."
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Bob Parnass, AJ9S - AT&T Bell Laboratories - att!ihlpy!parnass - (708)979-5414
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Guide to 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. Ham-
fests are repleat 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 complete.
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 per-
sonal experience with Uniden (the new manufacturer of Bear-
cat 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 shopping
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), Petersen,
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 techno-
logies 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, pro-
viding 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 diffi-
cult 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, resembled Altair or
PDP-8 computers, with a row of 16 or so toggle switches.
Instead of toggle switches, the Regency WHAMO-10 was pro-
grammed by breaking teeth from metal combs. The SBE Optis-
can (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 hys-
teresis 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 hobbyists 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 spec-
trum much easier than using the SEARCH mode on conventional
scanners. Selectable USB/LSB allows reception of new ampli-
tude 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 over-
load by strong signals when connected to outdoor antenna.
Too much play (hysteresis) in squelch adjustment - can be
improved by changing one resistor. Positive 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. Ser-
vice 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 frequencies.
Clock. High frequency of repair. Power transistors not
heat sinked adequately, causing heat damage 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 earlier vintage units. All
BC250s use custom ICs (e.g., IC6, a divider chip, mfd. by
Exar), which are now discontinued, so factory service is no
longer available from Uniden.
BC260: Super heavy duty metal cabinetry and lit controls,
aimed at mobile use for firemen, police, etc. Few frills,
only 16 channels, no aircraft, but generous coverage of
federal bands omitted in the older Bearcat scanners. Good
sensitivity. Lots of audio. Good internal construction.
Backlit keyboard allows operation in the dark, but the key-
boards on some units require high pressure to operate.
Brightness control for display and keyboard, but multiplexor
circuitry for vacuum fluorescent 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. 9 volt regu-
lator transistor Q28 (TIP29) may fail, causing blank display
while leaving audio intact. Method of connecting an exter-
nal 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 bat-
tery to disconnect from radio, resetting microprocessor and
clearing memories. No priority channel or aircraft band.
Some people swear by the BC100, others swear at them.
BC100XLT: Excellent 100 channel portable with 10 priority
channels. Unique feature tells whether a given frequency
has already been memorized. Generous coverage of conven-
tional 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 toggle
switches on front panel after looking up code in code book.
No frequency readout. Uses custom IC for CPU, now discon-
tinued, so factory authorized service is no longer avail-
able. 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 coverage.
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 overcome by connecting
two front ends via a capacitor). Easy to crystal: Radio
Shack crystals work well. TMRs usually $2 and up ad ham-
fests, often in poor condition. Don't pay more than $50,
even if mint. Front ends must be tuned for selected por-
tions within the bands for best sensitivity. Wide IF selec-
tivity troublesome in urban/suburban areas. Primitive digi-
tal scanning circuitry 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. Discontinued
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 circuitry make access to some com-
ponents difficult for servicing. 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 sen-
sitivity could be better. Spring contacts on membrane key-
board 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 keyboard
may need soldering after prolonged use.
- 2 -
M400: 30 channel replacement for K500, but now discontinued.
Service Search, but no aircraft. Easily programmable 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 synthesized
unit. Generous out of band coverage but no AM aircraft cov-
erage. 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 bat-
tery. 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 construction and shielding, but no
mobile mounting bracket or DC power cord. Soft touch mem-
brane keyboard. Good sensitivity 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 cover-
age. 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" channels.
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 aircraft.
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 provi-
sions 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 con-
trol 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 portable.
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 controlled 3
band unit. Also available under Plectron name but in dif-
ferent 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 incandescent 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!ihlpy!parnass (708)979-5414