PRO-20 Receiver 200-0101 Operation

PRO-20 Receiver
(200-0101)                 Operation                  Faxback Doc. # 39311


After batteries, crystal(s) and antenna (telescopic or flexible) have been
installed, your PRO-20 is ready to use.

Turn Power "on" by rotating VOLUME to the right.  Rotate SQUELCH to the
minimum position by rotating to the left.  Set all the Channel Lock-out
Switches "on" (in the up position, toward the LED indicators).  You should
hear a rushing sound from the speaker.  Rotate SQUELCH toward the right 
until the background noise abruptly stops.  You can't adjust SQUELCH
properly while listening to a station, so wait until signals cease.  If you
set SQUELCH correctly, the PRO-20 will appear "dead" until a signal comes
in; when a signal comes in, the Squelch circuit will "open up" and you'll
hear the signal.  When the signal ceases, the Squelch circuit will "close"
and cut out all sound until the next signal comes in.

If you want the PRO-20 to continuously scan the channels for which you have
crystals installed, you must adjust SQUELCH as previously instructed, then
set the Selector Switch to the SCAN position.  The PRO-20 will constantly
scan each channel in sequence; when a signal appears on one of the channels
the receiver will lock onto that channel and you will hear the signal.

If you do not want automatic scanning on one or more channels, switch their
Channel Lock-out Switches to the "off" position (down or away from the
LED indicator).

If you want to stay tuned to one channel only, set the Selector Switch to
the center position (stop scanning) and then press to the MANUAL position
momentarily to advance to the channel you want to listen to (as indicated
by the LED above that channel switch).  For MANUAL scanning, the receiver
can be either "squelched" (adjusted as previously indicated) or
"unsquelched" (SQUELCH control set to extreme left).  For AUTOMATIC
scanning, SQUELCH must be set to eliminate the background noise.

MAXIMUM SENSITIVITY RANGE

This Receiver will function very accurately down to 30 and up to 50 and
from 144 to 174 MHz, but with reduced sensitivity at the upper and lower
extremes.  For maximum sensitivity on the VHF-Lo band, the channel
frequencies you choose should be within 3 MHz of 40 MHz (that is, in the
spread of 37 to 43 MHz).  For the VHF-Hi band, stay within 4 MHz or 153
MHz (that is, 149 to 157 MHz).  The superior reception spread of 6 or 8
MHz (+/-3/4 MHz) can be moved up or down in either band of frequencies by
special realignment of the front end circuitry of this Receiver (which
should be attempted only by qualified Electronics Service Technicians who
have adequately calibrated, precision test equipment).

With such realignment, your Receiver can tune signals in the Ham bands and
other services.  We call your attention to the fact that this Receiver is
designed for reception of FM signals and thus can not be used for
monitoring AM signals (even though they may be within the frequency
coverage range).  These AM signals include much of the aircraft services.

TYPES OF SIGNALS YOU'LL BE ABLE TO MONITOR

Your community is alive with action - action which is constantly being
reported on the airwaves.  And your PRO-20 will automatically scan the
airwaves to bring you that action - your police force at work, a fire truck
on a mission, Ham Radio operators, highway and other emergency-type
services, some industrial services, some transportation services (taxi,
trucks, railroad), plus some Government services.  Lots of things are going
on that most of us are never aware of.  But, with the right frequency
crystals in your PRO-20 you can monitor such exciting signals.  You'll 
have to do a little investigating in your community to find out what 
services are active and on what frequencies.  You will find one of our
books to be very interesting and helpful in this area:  REALISTIC GUIDE TO
POLICE, FIRE, AND AIRCRAFT RADIO.

What to listen for and where?  That is a little difficult for a specific
answer.  Each area of the country can and will use different frequencies.
All we can do is give you some general pointers and let you take it from
there.

Find out if there is a local club which monitors these frequencies.  Often
a local electronics shop that does work on the equipment can give you the
channel frequencies used by local radio services.  A volunteer police or
fire employee can also be a good source of this information.

An interesting service is the Mobile Telephone.  FCC has assigned this
service channels in the range of 152.51 to 152.81 MHz at every 0.030 MHz
(channels are 30 kHz apart).

As a general rule on VHF, most activity will be concentrated between 153.785
and 155.98 and then again from 158.73 to 159.46 MHz.  Here you'll find
local government, police, fire and most such emergency services.  If you
are near a railroad yard or major railroad tracks, look around 160.0 to
161.9 MHz for them.

If you live near the coast or the Great Lakes, another interesting service
is Marine Radiotelephone (operates in the frequency range of 156 to 158
MHz).

Some of the more interesting frequencies are:

156.8 MHz for calling and distress safety
156.3 MHz for intership safety, plus search and rescue
157.1 MHz U.S. Coast Guard Liaison
156.425 MHz non-commercial ship-to-ship/ship-to-coast/coast-to-ship

Other frequencies may be of special interest; check with local Coast Guard
offices.

NATIONAL WEATHER SERVICE RECEPTION

Continuous weather broadcasts are transmitted 24 hours a day in many parts
of the country.  If you are using a crystal set to one of the three
channels assigned (162.55, 162.40 or 162.475 MHz), your PRO-20 will
automatically lock-in on that channel, since the broadcasts are continuous.
To prevent automatic locking, set the channel lock-out switch for that
channel to the "off" position (down).  When you want a weather report, set
the Lock-Out Button to the "on" position (up) for that channel.  Check 
with your local FCC office or the Weather Bureau to find out which of the
three frequencies (162.40, 162.55, or 162.475 MHz) is used in your area.

ACCESSORIES

Your PRO-20 can be powered from any source of 6 volts DC, negative ground,
by connecting the external power source to the PWR jack.  Using an AC
adapter will save on batteries; so, if you intend to use the PRO-20 in a
location where 120 volts is readily available, and it does not need to be
moved around, consider an adapter.  Radio Shack has two power adapters
which you might be interested in.  Catalog Number 20-189 is an adapter for
120 volts AC, specifically designed for Radio Shack's Pocket Scanners.  It
provides 6 volts DC and can be used either as a Charger or an AC Adapter.

Catalog Number 270-1561 is a power adapter for plugging into a cigarette
lighter socket in your vehicle and providing either 6 or 9 volts DC
(positive or negative - set for tip positive).  This will permit you to use
the PRO-20 in your car or truck without wearing down your batteries.  This
adapter can also be used with either CHG jack (to recharge Ni-Cads) or with
the PWR jack.

(km-05/06/1997)