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