245 lines
10 KiB
Plaintext
245 lines
10 KiB
Plaintext
ScanIntr.txt
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The following is a guide to the hobby of monitoring the
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Public Service bands, and some general tips for beginners to
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the hobby.
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This guide is broken down into 3 parts:
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(1) EQUIPMENT
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(2) SCANNING TIPS
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(3) SECTION 605, ECPA OF 1986, RESPONSIBILTY
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EQUIPMENT
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SCANNER TYPES: tunable, crystal, programable
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Tunable: Many types of tunable recievers are available to the
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scanner user. most of these have poor image rejection and
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were low-end units or mutiband type radios. These were
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subject to intermod and are only good for a few very strong
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signals and local coverage. Poor choice.
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Crystal: Crystal-controlled scanners have been around since
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the 60's. These radios very from 1 channel to as many as 16
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and are very good performers. They allow a set, 1 frequency-
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1 channel capability, and have good image rejection and
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filtering. These radios allow the first time user to sample
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frequencies at relativly low cost per channel, about 5
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dollars per crystal.
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Crystal controlled recievers are also good for professional
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users as the cost is low and most Public Service users only
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need to monitor a few set interim channels.
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Programable: These are by far the best for the serious
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scanner hobbiest. Programable recievers have good S/N
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figures, good image rejection, and for the most part very
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little intermodulation. They also allow greater flexability
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by allowing the user to change channels without spending
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money for crystals. Most all of the programable radios have
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LED or LCD readouts that give frequency, channel number, and
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other user information. All have memory backup to retain the
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contents of what has been programed. Programable recievers
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are by far the best cost per dollar units.
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These radios use to cost 300 to 700 dollars a few years ago
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but with computer technology, low IC cost , they now can be
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had for a little over 100.00. The main compromise in price
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these days for a programable scanner, is channels, frequency
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coverage, and special features.
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A minimum setup would be 20 channels, and the 118-136 Mhz
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aircraft band. 150.00 for this setup.
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* Scanner Tips *
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Now that the radio is sitting there, how do you know what
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frequencies to enter ? Most manuals that come with scanners
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have a spectrum breakdown to help new users find a ballpark
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area of interest.
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Frequency Spectrum Breakdown 30Mhz to 512Mhz
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30 to 50 low-band VHF
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military,police,fire,business, new cordless phones 46-49mhz
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mostly older systems in rural areas,mobile phone(not used in
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larger areas.paging systems used extensivly.Subject to long
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range skip conditions and solar activity.
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50 to 54 Mhz Amateur 6 meter band
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54 to 72 MHz TV Ch. 2-6
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72 to 88 Mhz low power industrial
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88 to 108 Mhz FM Broadcast Band
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108 to 136 MHz (AM) Aircraft band,Tower frequencies start at 118.000
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136 to 144 Mhz land mobile Military, Fed Govt.
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144 to 148 Mhz Amatuer 2 meter band
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148 to 150.6 Mhz Military, Fed Govt.
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150.6 to 152 Mhz Business
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152 to 153 Mhz RCC mobile phones and taxi cabs
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153 to 154 Mhz Public Transportation
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154 to 155 Mhz fire depts.
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155 to 156 Mhz State police
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156 to 157 Mhz Marine Band,ship to coast,ship to ship, Coast Guard,
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Bridges, toll Booths, Locks, inter-coastal waterways.
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157 to 158 Mhz Marine operations, Coast Guard. 156.800, Distress,Calling
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158 to 160 Mhz State Police
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160 to 162 Mhz Marine phone, various users
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162 to 174 Mhz Fed Govt. including all agencies
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174 to 220 Mhz TV Ch.7-14
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220 to 225 Mhz Amatuer radio
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225 to 400 Mhz UHF Aircraft (Military), Satellites, Experimental Work
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400 to 406 Mhz Wx Satelittes
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406 to 420 Mhz Fed Govt land mobile 430 to 440Mhz Fixed, Amateurs
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440 to 450 Mhz Amatuer 70cm Band
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450 to 453 Mhz Business, Power co.'s
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453 to 454 Mhz Local Police Depts.
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454 to 455 Mhz RCC Mobile Phone
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455 to 456 Mhz TV News Teams,Rebroadcasts
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456 to 458 Mhz Public Transport,Business,etc.
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458 to 460 Mhz Local Police Depts.
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460 to 460.5 Mhz Local Police Depts.
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460.5 to 461 Mhz Local Fire Depts.
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462 to 463 Mhz Business,GMR Service,REACT Teams
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463 to 464 Mhz Fire Dept. (Med Ch's)
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464 to 470 Mhz Public Safety,Industrial,Land Transportation
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470 to 512 Mhz Broadcasting,Shared With Local Public Safety
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and other users.
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As you can see there is a lot of ground to cover or
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monitor.
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Antennas: Most of the antennas that come with these radios are
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sufficient for local area coverage up to 75 mile radius from the listening
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post. If you can put up and external antenna, your range can be up to 200
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miles or more depending on the antenna type.
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External antennas:
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Omni: omnidirectional, 360 degree radius
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signal pickup.
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Yagi: directional, high gain
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beam: high gain, highly directional
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discone: high gain, wide bandwith, omnidirectional
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Your choice of external antennas depends on what services you are
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looking to hear most. Beam antennas are good for long range, single
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frequency coverage.
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Omni's pull in many signals, where discone and yagi's tend to have
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higher gain and wider bandwiths. A good compromise to all these antennas is
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the Discone, with wide coverage and good signal puling power.
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Once you have your radio and antenna set up, keep in mind these tips:
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keep your squelch control at a low theshhold level, you will hear more.
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Weak stations can sometimes be improved by re-orienting your antenna. Use
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NOAA Wx. stations for your area, when aligning your antenna or testing.
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These stations are continuous broadcast and can gauge reciever/antenna
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performance.
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Strong carriers can either be real signals or harmonics caused by
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other equipment, computers, printers, clocks, TV's, etc. Reorienting the
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scanner antenna sometimes will keep these signal from locking up the
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scanner. If the area you are in is really bad, you can buy filters that
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lock out these adjacent signals. Some phantom signals are caused by the
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radio itself. These are called "intermod" and "birdies", Intermod is caused
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by two internally generated signals causing a third order harmonic that
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locks up the scanner.
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"Birdies" are caused by clock and timing signals in microprocessor
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controlled radio's, most of these occurr at only a few frequencies over the
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entire range of the radio and can not be locked out. Most makers of
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scanners have installed filters to keep this from happening.
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SEARCH SCANNING:
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Searching for new frequencies with a programable scanner is
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accomplished by entering "upper and lower" frequency limits. A word of
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note, only enter a 1 megahertz search area. The reason for this is, the
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smaller the search area the more likelyhood of finding new frequencies .I.E
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155-156 mhz.
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Another tip is to put the delay function on during search mode. This
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allows you to note the frequency and also allows for a reply. When
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monitoring a transmission, take notes as to ID codes and or FCC call
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letters. Most public service users are required to ID their station at
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least once every 5 minutes.
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OTHER TIPS:
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Inclement weather, storms, major events etc. have a tendency to
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increase radio traffic. During storms, monitor local road crews, rescue
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services, and other public service bands. The local officials generally are
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the people " out in the thick of it", and you can gleen much info on area
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road conditions or detours etc. from this monitoring.
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MOBILE INSTALLATIONS:
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Check first your local laws covering radios capable of monitoring
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police frequencies in a vehicle, before installing a scanner in your car.
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The city of Philadephia at one time had a law making it illegal and a 1st
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offense punishable by a 500.00 dollar fine and confiscation of the
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equipment.
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Most radios today have a 12 volt DC negative ground option or jack for
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modile use. Once a suitable location and power requirements are met, all
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that is left is mounting the unit and running the antenna. These
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instructions are generally included in the owners manual.
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**** SECTION 605, ECPA, AND RESPONSIBILITY ****
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As a hobbiest, it is important to observe a few rules pertaining to
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the scanner hobby. First use of information overheard via a scanner for
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personal gain, criminal purposes, or interference with public safety, is
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not only illegal but strongly enforced. Chasing ambulances, fire trucks
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etc. will cause you to quickly loose your licence and may get you arrested.
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Other responsibilty falls into one important category: Restraint. If you
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happen to stumble across a set of frequencies used by local or federal law
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enforcement officials, keep in mind that disclosure of any information you
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may hear could interfere with a drug stake-out, hostage situation, or other
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life threatening senario.
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There are situations where news media people, in their zeal to cover a
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story have caused the deaths of hostages after showing up on a scene after
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overhearing the operation on their scanners. Police, Fire and Goverment
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officials have jobs to do, and don't need interference from the public.
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Keep what you hear to yourself.
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The Electronic Communications Privacy Act of 1986
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This bill which is a bill designed by the cellular lobby (and others)
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to restrict what you can and cannot listen to. In it's present form it
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makes it illegal to "willfully" monitor any two-way communication primarily
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seen as closed to the public.
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This includes mobile phone, STL links, SCA services, and certain other
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services, this law is seen by the FCC and the Justice Dept. as being
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unenforcable, but as with any bad law it will no doubt have to be tested in
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court before it is reformed or rewritten.
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Footnote: Scanning can be and enjoyable hobby and give the listener a
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better insight into where his/her tax dollars are being spent. Public
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servants are there for helping the people and enforcing the laws. The
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United States is one of the few countrys in the world where monitoring is
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allowed, It is a privilage that few other countries show their citizens. Be
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responsible and enjoy!
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