In the early days of radio engineering, it was necessary to
calculate every value used in determining coverage and antenna design
manually. Slide rules were the norm, and many engineers carried one in
a hip holster — well, almost. My slide-rule case certainly had a
belt slot in it.
This Dataworld map shows the area where
a new FM transmitter can be located and still meet all FCC Rule
Today the computer and the calculator have replaced the slide rule.
Forty years ago many engineers rented a Burroughs or similar machine to
perform the iterations needed to design a directional AM antenna. It
was left to Andy Ring, P.E., former FCC chief engineer and legendary
consulting engineer, to develop and offer a calculating/computerized
service. He named it Dataworld, and in addition to calculating services
it offered a trustworthy database.
From the beginning
Over time, DataWorld's offerings grew from simple AM directional
antenna design calculations and a pattern book of all U.S. AM stations,
to complete services in all branches of radio, TV and most RF work. I
have found the DataWorld station database to generally be more accurate
than the FCC's database.
DataWorld's CD database of all US stations includes pertinent
station details. The data also extends into cell and wireless, and all
microwave. The scope is worldwide, and topographic data is available on
RadioSoft's ComStudy 2.2 is a complete engineering package for
performing AM, FM and TV propagation studies. Also included are
groundwave, skywave 50%, skywave 10%, Region 2 skywave 50% and Region 2
skywave 10% contours. It will also perform ground conductivity
The FM program is full featured for all types of FM studies
including low power. Propagation models such as Longley-Rice,
Bullington, Okumura and Epstein-Peterson are available. Contour
capabilities include F (50,50), F (50,10) and Point-to-Point (PTP)
service and interfering contours.
The program can also download the latest FCC license data and then
assist the user in searching for possible new frequencies or locations
by use of the frequency finder and allocation program. It will then
rank these possibilities for the best possible chances of being
Lots of data
REALcoverage from CMBE offers several services. The type of station
and the necessary technical parameters, such as location, height above
ground, power, gain, losses and antenna patterns, are input into the
system; all the stations of the network appear instantaneously on the
map and are integrated in databases for further studies.
The system integrates several propagation models including FCC 98,
Longley-Rice, Fresnel, Deygout 94, Okumura-Hata, ITU-R.P.370,
ITU-R.P.525/526 and NBS 101, as well as several customized propagation
models. The calculation incorporates free space propagation,
diffraction, refraction and reflection. Physical interactions, like
earth curvature, climate attenuation and ground occupancy linear
attenuation are also considered.
Coverage is calculated for each point of the terrain and displayed
on two-dimensional or three-dimensional maps. Composite and best server
coverage, overlap and hand-over between stations, and other detailed
studies are all available with automatic frequency assignment and
optimum spectrum occupancy, re-using frequencies when possible to
Computer modeling, like this from
RadioSoft, can make planning a site change much easier.
For microwave link projects, terrain profiles can be instantaneously
extracted between two stations and complete path budget calculations
generated for analog or digital stations.
This service uses internal databases that allow instant managing of
as many sites as necessary. It can also integrate as standard the
possibility to connect to external sources through an existing local or
distant network (import and re-using of existing databases and share of
technical information on a large scale).
Comprehensive link path analysis is standard within REALcoverage,
showing a full and detailed cross section of the terrain and path
V-Soft Communications offers allocation and coverage mapping for the
AM standard band. Its maps will plot AM coverage signal contours and
contour overlap based on the FCC AM rules. The maps apply the M3 or R2
ground conductivity curves, depending on which is needed. Using the
same software developed for its long list of broadcast technical
consultants and engineering clients, V-Soft Communications can provide
custom mapping and engineering studies for just about every engineering
V-Soft maps can incorporate Longley-Rice, TIREM,
Okamura/Hata/Davidson, Cost-231/Hata, PTP and the more common FCC
standard contour method. The atlas-quality maps use advanced polygon
shaping. V-Soft can produce representations of coverage from street
level to statewide coverage. Multiple stations can be plotted on the
same maps to show group coverage. Demographic information is included
with each coverage map, and zip codes, FCC-registered towers and
individual U.S. Census year 2000 centroids can be plotted on maps.
Other mapping options for the V-Soft client include incoming or
outgoing interference studies. The studies automatically identify the
stations to which interference is caused as well as those stations that
cause interference to the client's reference station facilities. Types
of interference map studies include FM, TV and DTV. NCE to channel-six
TV interference maps and analysis are also performed.
V-Soft Communications also gives you the option to make your own
maps on your own computer because all of the software it uses to
prepare its maps and studies is available for purchase.
A newer entry into the field of engineering software is
rfEngineers.com. Its product, RfDetective-FM, helps FMs change class or
power or locate frequencies for new FM stations. It also displays
antenna height, location and channel of existing broadcasting stations.
Four editions of rfDetective-FM are available. The Pro and Standard
editions can create and modify jobs. The Pro edition can also create
its own database directly from raw FCC data that can be downloaded from
the FCC website. The Light edition can read and modify jobs created
with the Pro or Standard editions, but cannot create a new job. A
Reader edition is also available.