© Chezradio 2012
ChezRadio
Airwave Freedom
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 104 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.
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 User Manual. 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.
Range Optimization
Short range license-free radio broadcasting solutions