Overview
The original intention of the FCC was
to allow broadcasting around the home. Their regulations
achieved this by specifying low input power and electrically
short antennas. The purpose of this was to minimize any
interference with commercial radio stations and their listeners.
What is the range?
This is probably the #1 question asked.
Range for low power transmitters can vary greatly due to
many factors:
radio signals from other stations
on the same frequency
obstructions such as buildings and trees
transmitter height
quality of the grounding
electrical interference from power lines
sensitivity of the radio receiver
Typically you can expect a range of of between 1/4 mile
to 1 mile when mounted on the ground and 1/2 to 2 miles
when elevated 20 ft. These installations assume you have
a good ground. good soil conductivity, low noise and few
obstructions in your area. Less than ideal conditions will
reduce range.
For best results, we have compiled
the following as a guide:
Tip #1
Pick the clearest/quietest frequency
in your area that you can. Competing with a commercial radio
station, even if far away and weak will severely reduce
your range.
Tip #2
If you want to transmit at night, make
sure that is free also. This may be difficult because at
night there may be a cluster of distant stations on every
frequency (even if it sounds fairly clear).
Tip #3
Mount the Procaster™ elevated about
25ft in an open area as far away from buildings, trees and
electrical overhead wires as possible. SAFETY WARNING -
Never install an antenna close by to any electrical service!
Tip #4
Make sure your ground is good. The FCC
rules allow for a total of 3 meters (118 in) for antenna,
transmission line and ground lead.
The Procaster™ has a fixed
103 in antenna length, no transmission line and a ground
lug which must be connected to a ground point for lightning
protection. That implies that the "ground lead"
from the ground lug to the ground point can be up to 15
in long to comply with the 15.219 rules.
If you run a long wire
from the ground lug to earth ground, an FCC agent might
disallow it if he thinks that this ground lead could radiate
and thus effectively extend the antenna length in violation
of the 15.219 rules. Adding a choke right at the Procaster
ground lug may be acceptable to the FCC agent as effectively
de-coupling the long ground lead and preventing it from
radiating.
Another method which has been
acceptable by some FCC agents in the past is to connect
the "ground lead" to a large metal structure,
e.g. a metal tower or metal roof.
FCC agents do have different
opinions and inspection outcomes have varied according to
past history. If you are notified that your installation
is not compliant, be courteous and polite to the agent and
seek to correct the issue promptly. FCC agents have a job
to do and their interpretations may vary. Do not contact
the FCC office and ask if your installation is OK, they
are not interested, however, they may contact you because
somebody complained. If this happens, just give them the
Procaster FCC identification VCJ-AMTX100 which is located
on the front label and assures them that your equipment
is legal. Chances are they won't waste their time and gas
coming out to visit you.
Bear in mind that the Procaster™
has lightning protection built in to prevent lightning from
entering into a residence and possibly injuring somebody.
For safety reasons, it is essential that proper grounding
is implemented and that all local electrical safety codes
are observed. Safety is priority one.
Tip #5
It is VERY important that the Procaster™ antenna is
tuned to resonance properly. Follow the tuning procedure
in the Installation & Operation section. An improperly
tuned system will have poor range. When optimally tuned,
the RF antenna voltage becomes highest, yielding best range.
Tip #6
Range is usually higher in the countryside
compared to the city due to lower electrical noise and shielding
effects. This has to be taken into account when deciding
on your expected coverage area.
Tip #7
Don't be surprised if range is more in
one direction than another: this is usually caused by obstructions/interference.
Tip #8
Range will vary due to seasonal changes
in weather and humidity. Ground conductivity affects range
greatly and can vary depending on your geographical location
and whether the ground is wet or dry.
Tip #9
Hum may be a problem in your installation.
It is usually caused by small differences in AC line voltages
within your system which are small, but when amplified,
are audibly noticeable. You can obtain ground loop isolators
(transformers), which isolate and remove hum. Some available
models:

Radio Shack #270-054
or a higher quality, better
frequency response unit from Jensen.

Jensen CI-1RR