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ScanIntr.txt
The following is a guide to the hobby of monitoring the
Public Service bands, and some general tips for beginners to
the hobby.
This guide is broken down into 3 parts:
(1) EQUIPMENT
(2) SCANNING TIPS
(3) SECTION 605, ECPA OF 1986, RESPONSIBILTY
EQUIPMENT
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SCANNER TYPES: tunable, crystal, programable
Tunable: Many types of tunable recievers are available to the
scanner user. most of these have poor image rejection and
were low-end units or mutiband type radios. These were
subject to intermod and are only good for a few very strong
signals and local coverage. Poor choice.
Crystal: Crystal-controlled scanners have been around since
the 60's. These radios very from 1 channel to as many as 16
and are very good performers. They allow a set, 1 frequency-
1 channel capability, and have good image rejection and
filtering. These radios allow the first time user to sample
frequencies at relativly low cost per channel, about 5
dollars per crystal.
Crystal controlled recievers are also good for professional
users as the cost is low and most Public Service users only
need to monitor a few set interim channels.
Programable: These are by far the best for the serious
scanner hobbiest. Programable recievers have good S/N
figures, good image rejection, and for the most part very
little intermodulation. They also allow greater flexability
by allowing the user to change channels without spending
money for crystals. Most all of the programable radios have
LED or LCD readouts that give frequency, channel number, and
other user information. All have memory backup to retain the
contents of what has been programed. Programable recievers
are by far the best cost per dollar units.
These radios use to cost 300 to 700 dollars a few years ago
but with computer technology, low IC cost , they now can be
had for a little over 100.00. The main compromise in price
these days for a programable scanner, is channels, frequency
coverage, and special features.
A minimum setup would be 20 channels, and the 118-136 Mhz
aircraft band. 150.00 for this setup.
* Scanner Tips *
Now that the radio is sitting there, how do you know what
frequencies to enter ? Most manuals that come with scanners
have a spectrum breakdown to help new users find a ballpark
area of interest.
Frequency Spectrum Breakdown 30Mhz to 512Mhz
30 to 50 low-band VHF
military,police,fire,business, new cordless phones 46-49mhz
mostly older systems in rural areas,mobile phone(not used in
larger areas.paging systems used extensivly.Subject to long
range skip conditions and solar activity.
50 to 54 Mhz Amateur 6 meter band
54 to 72 MHz TV Ch. 2-6
72 to 88 Mhz low power industrial
88 to 108 Mhz FM Broadcast Band
108 to 136 MHz (AM) Aircraft band,Tower frequencies start at 118.000
136 to 144 Mhz land mobile Military, Fed Govt.
144 to 148 Mhz Amatuer 2 meter band
148 to 150.6 Mhz Military, Fed Govt.
150.6 to 152 Mhz Business
152 to 153 Mhz RCC mobile phones and taxi cabs
153 to 154 Mhz Public Transportation
154 to 155 Mhz fire depts.
155 to 156 Mhz State police
156 to 157 Mhz Marine Band,ship to coast,ship to ship, Coast Guard,
Bridges, toll Booths, Locks, inter-coastal waterways.
157 to 158 Mhz Marine operations, Coast Guard. 156.800, Distress,Calling
158 to 160 Mhz State Police
160 to 162 Mhz Marine phone, various users
162 to 174 Mhz Fed Govt. including all agencies
174 to 220 Mhz TV Ch.7-14
220 to 225 Mhz Amatuer radio
225 to 400 Mhz UHF Aircraft (Military), Satellites, Experimental Work
400 to 406 Mhz Wx Satelittes
406 to 420 Mhz Fed Govt land mobile 430 to 440Mhz Fixed, Amateurs
440 to 450 Mhz Amatuer 70cm Band
450 to 453 Mhz Business, Power co.'s
453 to 454 Mhz Local Police Depts.
454 to 455 Mhz RCC Mobile Phone
455 to 456 Mhz TV News Teams,Rebroadcasts
456 to 458 Mhz Public Transport,Business,etc.
458 to 460 Mhz Local Police Depts.
460 to 460.5 Mhz Local Police Depts.
460.5 to 461 Mhz Local Fire Depts.
462 to 463 Mhz Business,GMR Service,REACT Teams
463 to 464 Mhz Fire Dept. (Med Ch's)
464 to 470 Mhz Public Safety,Industrial,Land Transportation
470 to 512 Mhz Broadcasting,Shared With Local Public Safety
and other users.
As you can see there is a lot of ground to cover or
monitor.
Antennas: Most of the antennas that come with these radios are
sufficient for local area coverage up to 75 mile radius from the listening
post. If you can put up and external antenna, your range can be up to 200
miles or more depending on the antenna type.
External antennas:
Omni: omnidirectional, 360 degree radius
signal pickup.
Yagi: directional, high gain
beam: high gain, highly directional
discone: high gain, wide bandwith, omnidirectional
Your choice of external antennas depends on what services you are
looking to hear most. Beam antennas are good for long range, single
frequency coverage.
Omni's pull in many signals, where discone and yagi's tend to have
higher gain and wider bandwiths. A good compromise to all these antennas is
the Discone, with wide coverage and good signal puling power.
Once you have your radio and antenna set up, keep in mind these tips:
keep your squelch control at a low theshhold level, you will hear more.
Weak stations can sometimes be improved by re-orienting your antenna. Use
NOAA Wx. stations for your area, when aligning your antenna or testing.
These stations are continuous broadcast and can gauge reciever/antenna
performance.
Strong carriers can either be real signals or harmonics caused by
other equipment, computers, printers, clocks, TV's, etc. Reorienting the
scanner antenna sometimes will keep these signal from locking up the
scanner. If the area you are in is really bad, you can buy filters that
lock out these adjacent signals. Some phantom signals are caused by the
radio itself. These are called "intermod" and "birdies", Intermod is caused
by two internally generated signals causing a third order harmonic that
locks up the scanner.
"Birdies" are caused by clock and timing signals in microprocessor
controlled radio's, most of these occurr at only a few frequencies over the
entire range of the radio and can not be locked out. Most makers of
scanners have installed filters to keep this from happening.
SEARCH SCANNING:
Searching for new frequencies with a programable scanner is
accomplished by entering "upper and lower" frequency limits. A word of
note, only enter a 1 megahertz search area. The reason for this is, the
smaller the search area the more likelyhood of finding new frequencies .I.E
155-156 mhz.
Another tip is to put the delay function on during search mode. This
allows you to note the frequency and also allows for a reply. When
monitoring a transmission, take notes as to ID codes and or FCC call
letters. Most public service users are required to ID their station at
least once every 5 minutes.
OTHER TIPS:
Inclement weather, storms, major events etc. have a tendency to
increase radio traffic. During storms, monitor local road crews, rescue
services, and other public service bands. The local officials generally are
the people " out in the thick of it", and you can gleen much info on area
road conditions or detours etc. from this monitoring.
MOBILE INSTALLATIONS:
Check first your local laws covering radios capable of monitoring
police frequencies in a vehicle, before installing a scanner in your car.
The city of Philadephia at one time had a law making it illegal and a 1st
offense punishable by a 500.00 dollar fine and confiscation of the
equipment.
Most radios today have a 12 volt DC negative ground option or jack for
modile use. Once a suitable location and power requirements are met, all
that is left is mounting the unit and running the antenna. These
instructions are generally included in the owners manual.