💾 Archived View for gemini.spam.works › mirrors › textfiles › hamradio › scanintr.txt captured on 2023-01-29 at 08:10:10.
⬅️ Previous capture (2020-10-31)
-=-=-=-=-=-=-
Introduction to Scanning
by Bob Parnass, AJ9S
[NOTE: This article may not be reproduced in whole or in
part in bulletin boards, networks, or publications which
charge for service without permission of the author. Free
distribution is encouraged.]
This introduction is intended for people new to the scan-
ning hobby. It tells where you can buy your first scanner,
what features it should have, how to get frequency informa-
tion, and mentions a few scanner clubs worth joining.
Why Scanning?
Every day and night, scanner hobbyists are entertained by
what they overhear on their radios. Police cars, fire
engines, ambulances, armored cars, trains, taxis, air-
planes, and buses are all equipped with radios and you can
listen to them. You can monitor the local sheriff and fire
departments to hear about events "as they happen," before
the news reporters hear about them. Hostage dramas, bank
robberies, car crashes, chemical spills, tornado sightings
are all fair game. In a single afternoon, you can hear a
high speed police chase, Drug Enforcement agents on a sting
operation, and undercover FBI agents as they stakeout a
suspect.
How about listening to a presidential candidate discuss
strategy with his advisor from a 415 MHz radiophone in Air
Force 1, or a team of G-men protect him while transmitting
in the 167 MHz range?
Listen to your neighbors deal drugs over their cordless
telephone, or as their conversations are picked up and
transmitted over the airwaves by their sensitive baby moni-
tor intercom. Yes, it's legal to listen, and it's all
there in the 46 and 49 MHz ranges.
Stay ahead of road conditions by listening to highway road
crews, snow plows, and traffic helicopter pilots.
Take your scanner to sporting events and listen to race car
drivers, football coaches, etc., in the 151, 154, and 468
MHz ranges.
Listen to airline pilots as they talk with air traffic con-
trollers and their companies between 108 and 137 Mhz.
Monitor the everyday hustle and bustle of businesses, from
cable TV repair crews tracking down pirate descrambler
boxes, to security guards at your nuclear power plant or
mall security guards chasing a shoplifter.
You can even listen to the order taker's wireless micro-
phone at the local McDonald's restaurant on 154.6 and 35.02
MHz!
Is Scanning Legal?
In the United States, scanning from your home or at work is
perfectly legal in most situations. The Electronic Commun-
ications Privacy Act of 1986 made it illegal to listen to
mobile phones, and a few other types of communication, but
many scanners cover these frequencies, and it's clear that
Americans still listen to whatever they want in the privacy
of their own homes despite the ECPA.
Speaking of privacy, federal law also requires you to keep
what you hear to yourself and not use the information you
hear on your scanner for personal gain.
Be aware that California, Florida, Indiana, Kentucky,
Michigan, Minnesota, Nebraska, New Jersey, New York, North
Dakota, Oklahoma, South Dakota, Tennessee, and Vermont have
laws pertaining to scanning while in your car. Indiana
restricts some portable scanners. You can find out about
these restrictions in a 39 page paperback, ANARC Guide to
U. S. Monitoring Laws, compiled by Frank Terranella, avail-
able for $7.50 from ANARC Publications, P.O. Box 462,
Northfield, MN 55057.
What Scanner Should I Buy?
Radio Shack, Uniden (Bearcat and Regency brands), and Cobra
offer a wide choice of scanners. Personally, I don't
recommend AOR brand scanners.
Scanners are available in two varieties: crystal controlled
and programmable. The crystal controlled models are
cheaper, but require the user purchase and install a $5
crystal for each frequency of interest. Programmable (syn-
thesized) units don't require crystals and usually have a
keypad that permits you to store frequencies into channels.
Programmables are now so cheap it doesn't make sense to buy
a crystal unit as your main scanner unless you get it for
under $45 or so.
You can get a battery operated hand held scanner, a bigger
"base" scanner which is powered from an AC outlet, or a
mobile scanner which connects to your auto's electrical
system.
Make sure your first scanner:
1. has a "search" feature, which allows it to search all
the frequencies between two frequency limits of your
choosing. The lowest cost programmables can't search.
2. covers the 800 MHz band unless you live in a very
rural area where this band is not used. Usage of the
800 MHz band is growing by leaps and bounds.
If you're not sure whether you'll like scanning, don't want
to spend much money, a 16 channel radio will do. In gen-
eral, the more channels and banks, the better.
Deluxe scanners can be controlled by a personal computer,
although this feature isn't important to most scanner own-
ers.
Currently, the more popular scanners include the
Uniden/Bearcat 760XLT (a/k/a 950XLT) and Radio Shack PRO-
2004 and PRO-2005 base/mobiles, and the Uniden/Bearcat
200XLT (a/k/a 205XLT) and Radio Shack PRO-34 portables.
All scanners come with a built in antenna, permitting
reception up to about 20 miles or so. Outdoor antennas can
extend reliable reception to 100 miles or more.
Where Can I Buy A Scanner?
Almost every community has at least one Radio Shack store,
and you can find scanners there. Discount chain stores
like Service Merchandise sell scanners, but carry just a
few models. Department stores, like Sears and Montgomery
Wards, sometimes offer scanners, although at high prices.
The best deals on new scanners are from reputable mail
order firms like Grove Enterprises (Brasstown, NC), Scanner
World (Albany, NY), or National Tower Company (Shawnee Mis-
sion, KS). Many ham radio dealers, like Amateur Electron-
ics Supply (Milwaukee, WI), also sell scanners. See the
shortwave "welcome" article for the addresses of other
scanner suppliers.
Used scanners may be found at hamfests, flea markets, or
listed in the classified advertisement section of your
newspaper.
Where Can I Obtain Frequency Information?
To avoid chaos, the FCC licenses two-way radio users and
assigns them specific frequencies. Groups of frequencies
are allocated to specific types of users, so you won't usu-
ally find fire departments using the same frequencies as
taxi drivers, for example.
Scanner enthusiasts can obtain frequency information from
several sources, including books, government microfiche
records, or other listeners.
Books: The most convenient source of fire, police, and
local government frequencies is the Police Call Radio
Guide, published each year in 9 regional volumes by Hollins
Radio Data, and sold at Radio Shack and larger book stores
for about $7.
I also recommend Richard Prelinger's 1985 book, Monitor
America, published by SMB Publishing, and available from
Grove Enterprises for about $15. Although somewhat out of
date, this single edition contains 582 pages of police,
fire, local government, news media, sports, national park,
and commercial broadcast frequencies for all 50 states. It
contains detailed communications system profiles and pre-
cinct maps for major metropolitan areas. Police and fire
radio codes and unit identifiers unique to local agencies
are listed for several cities. This differs from Police
Call, which gives a more sterile, but uniform treatment of
licensees, listing even the smallest of towns.
Uniden has published several regional directories using the
"Betty Bearcat" name, although there are much better direc-
tories available from Scanner Master (Newton Highlands, MA)
for some regions.
The most readily available source of sensitive US govern-
ment frequencies is still Tom Kneitel's 168 page Top Secret
Registry of US Government Radio Frequencies. Published by
CRB Research, the 6th edition is available from Grove
Enterpises for about $19. Kneitel's book contains fre-
quency listings for NASA, military, FBI, Secret Service,
DEA, IRS, Border Patrol, arsenals, ammunition plants, mis-
sile sites, and others in the 25 to 470 MHz range.
Magazines: Although national in circulation, local fre-
quency information is sometimes available in Grove's Moni-
toring Times and Kneitel's sensationalistic Popular Commun-
ications. The best frequency lists are often found in club
publications, discussed later.
Government Records: Every year, the US Government sells FCC
license information, in the form of microfiche, floppy
disk, and magnetic tape, to the public through the US
Department of Commerce National Technical Information Ser-
vice (NTIS). The high cost of buying government records
limits their appeal to hardcore enthusiasts. You can write
for a catalog of FCC Master Frequency Database items to the
NTIS, 5285 Port Royal Road, Springfield, VA 22161.
Do Your Own Frequency Detective Work
When you try listening to a frequency for the first time,
you'll want to know who you're hearing.
Although FCC rules require radio users to identify their
operations with their assigned call letters, most ignore
the regulation. This often makes it difficult to know who
is transmitting.
There is a challenge in deriving new spectrum usage infor-
mation on your own. Sometimes it requires several days of
listening, taping, and compiling fragments of information.
Other times, the frequency information is there for the
taking - without hassle.
You can approach from two directions:
1. Listen first: Monitor a frequency or frequencies, and
try to determine who's transmitting and what purpose
the channel serves. Once you identify the user, log
the information.
2. Compile first: Take advantage of opportunities, such
as examining the frequency label on a guard's radio,
or reading the FCC license hanging on the "radio
room" wall, to compile frequency lists, then monitor
the listed frequencies to confirm that they are
really in use. Readers are urged to abide by the
rules of good taste and local laws in the quest for
frequency information. Don't trespass, wait for an
invitation.
Most listeners use a combination of both approaches.
You can examine the FCC license on premise. I have found
the actual FCC radio license, complete with frequency
assignments, hanging on the walls of places like the mall
security office or company guard shack. You can examine
the labels on radio equipment. Frequency information is
engraved on labels on the back of many walkie-talkies, or
inside the battery compartment, like in the Motorola HT220
model. Most pagers have labels on the bottom or inside.
Like passwords taped onto terminals, it's not uncommon to
find Dymo tape labels embossed with frequencies or call
letters glued to the front of base stations.
You can make your own opportunities for eyeing the equip-
ment or take advantage of "open house" events. If informa-
tion is displayed publicly, then a reasonable person could
assume it's not government secret. Hobbyists are urged to
exercise a modicum of restraint and good judgement, how-
ever.
How Can I Use Equipment
to Uncover New Frequencies?
If you don't know the exact frequency, but have a general
idea of the range (e.g. 150 - 152 MHz), use your scanner's
"search" mode. Most programmable scanners afford the abil-
ity to search between two frequency limits set by the user.
Three models, the ICOM R7000, Bearcat 250, and Regency
K500, have the ability to automatically store active fre-
quencies found during an unattended search operation.
To find the frequency of a hotel communications system, one
fellow installed his Bearcat 250 in his car and parked in
the hotel lot, leaving the scanner in the "search and
store" mode. He left the antenna disconnected so the
scanner would only respond to a transmitter in the immedi-
ate vicinity.
Aside from a scanner and antenna, the most useful piece of
equipment for sleuthing is a voice actuated (VOX) cassette
tape recorder. You don't need a high fidelity model or
anything fancy, a Radio Shack CTR-75 or CTR-82 will do.
It's best to use a shielded cable to feed the scanner audio
into the recorder rather than relying on the recorder's
internal microphone.
VOX recorders allow one to compress a whole day's worth of
monitoring onto a single tape. I often leave a recorder
"armed" and connected to a scanner at home while I am at
the office or doing something else. When call letters are
mumbled, I can play and replay the tape until I hear and
understand them.
Test equipment can aid in the quest for new frequency
information. I've used a spectrum analyzer connected to an
outside antenna, and a frequency counter for close-in work.
Are There Any Scanner Clubs?
One of the best parts of the hobby is sharing it with other
radio buffs. Trading information with other hobbyists
about frequencies, communication systems, and receiving
equipment is more valuable than any pile of magazines.
The world's largest scanner club is the Radio Communica-
tions Monitoring Association (RCMA). Founded in 1975, the
RCMA is the "first national and international organization
of monitor radio listeners." There are several regional
chapters which hold regular meetings. Club dues are $18.50
per year, which includes a monthly newsletter of about 95
pages. Although the focus is on VHF and UHF ranges, there
is coverage of HF utility stations below 30 MHz.
Inquiries about RCMA membership should be sent to RCMA Gen-
eral Manager, P.O. Box 542, Silverado, CA 92676, USA.
A smaller club is the All Ohio Scanner Club. Its bimonthly
publication, The American Scannergram, is about 60 pages
long. Although concentrating on Ohio, there is frequency
information from other states, and plenty of good product
reviews and scanning tips.
Annual dues are $15 and more information is available from
All Ohio Scanner Club, 50 Villa Road, Springfield, OH
45503.