Broadcast engineers are commonly asked if there is any way to improve or upgrade an FM broadcast facility. In some cases, a small or out-of-market station might want to improve its signal into a nearby, more densely populated community. Sometimes there is interest in finding a new tower site for a station. The upcoming FCC auction of vacant FM allotments has engineers wondering if they might have value beyond their opening bid price. For all of these questions a tool is needed that will conduct FM channel frequency searches. FMCONT is one such tool.
FMCONT is part of a suit of software tools offered by V-Soft Communications. FMCONT is a software module that performs channel searches through a current FCC FM broadcast records database. The search results show a useable area to which a station may upgrade, or a new station might be dropped in.
What it does
FMCONT has matured over the years into a one-stop toolbox for all things related to FM station allocations spacings. Features include instant contour-to-contour mapping of Part 215 directional rule short-spaced stations and contour-to-contour non-commercial station signals. FMCONT provides settings to look at translator stations, low-power FM (LPFM) stations and full-service FM broadcast facilities. The software automatically considers TV interference issues, when applicable, and includes intermediate frequency (IF) station separations in the tables. The user can move or model a prospective tower site simply by pointing to a spot on the map and clicking. FMCONT then automatically recalculates all of the data using the new reference location for its measurements. Alternately, a user can thumb through the entire FM band at the site under study quickly.
Performance at a glance
Intuitive, east-to-use software
Examine entire FM band at a reference location
Find open channels for upgrades and drop-ins
One-touch contour-to-contour evaluation of short-spaced and NCE allotments
Prints tables, reports and exhibits for FCC applications
Quickly model what-if station relocation scenarios
FMCONT produces print-outs showing a spacings table of the reference channel (suitable for filing with an FCC application), preclusion studies showing all or part of the FM band at the reference site with every station protection that may preclude the site's use, contour-to-contour overlap maps, spacings maps, station database record information and an informative help file.
How it works
FMCONT is a Windows-based program. After starting the program the user enters reference data for a site under study by using the menus to call up a particular station record from the FCC database, or by manually entering site information. The intuitive software offers default settings that adapt to the reference entry to define the study as a full service, translator or LPFM study. The program adapts its spacings methods to accommodate the commercial or non-commercial part of the FM band based on the reference site entry. The user may choose to include LPFM and translator records, auxiliary standby transmitter records and whether to include historical allocation markers or not. On my computer, a typical Class C reference search in Denver took four seconds to compile the entire FM band.
Once compiled, the user may interface with the software in any one of several windows that are interactive and tied together. The “home” window is a spacings table that displays the reference station and every pertinent database record. For each record the distance and bearing from the reference are provided along with the FCC required distance and a column that shows the margin between the required and actual distances. Mexican and Canadian database records appear where appropriate with separation relationship information from the appropriate treaty.
The user may open a map window that shows the FCC required distance circles from each database record with the reference site at the crosshair in the center of the map. Cities may be selected on or off while the user also selects an appropriate zoom level and selects how many stations to show. The circles on the map are green when fully spaced to the reference or red if they are short. The software can automatically flag present day Class C FMs that are candidates to become C0 stations under the new rules (coloring their circles different so they stand out). The user may actually select a short-spacing display on the map, which quickly reduces the circle radii to show the minimum distance separation requirements of 47 CFR 73.215.
If you click on a station's call sign you may click a map button that instantly plots the contour-to-contour relationship of the station whose call sign you clicked on vs. the reference station. Note that this contour-to-contour plot, and the table display, feed on a terrain database so there's no need to switch to some other program to ensure it all works in the real world. If the station uses a directional pattern a circular plot of the pattern appears. Click on the plot and an interactive antenna pattern editor opens, which allows the alteration of pattern field points simply by dragging the points on the circular plot. Contours shown in the open map window instantly move to conform to the new pattern settings.
The Find Station utility helps to locate potential sites for new stations.
The software permits all of the database records to be manually adjusted, so the user can change each station and see the results on the spacings map and tables instantly. This means users can go through a “what if” scenario quickly and see what would happen if some other station were to downgrade or go directional — or change its tower site.
From each window users may go up or down one channel (or several), easily upgrade or downgrade the reference facility or investigate the entire FM band at the reference site. There are print options that let a user print out application exhibits, study overlap maps or station database information.
There is a seek option. From any reference site, after selecting the particular class or facility desired, the user can press the seek button to have the software instantly display any and all band openings where a station could reside on the FM band at the reference coordinates.
A directional pattern can be drawn and modified to fit a desired coverage.
Another feature worth mentioning is the ability to save a useable area file that exports the map display file so it may be imported directly into a Probe 3 map (another V-soft software product). Probe 3 offers many advanced mapping features (including the importation of every tower in the FCC Antenna Structure Registration database) to help the user define a relocation search area or make some other more detailed exhibit.
Documentation, support and drawbacks
The documentation with FMCONT is complete. A nice binder of information is available with the product. All of the documentation is also included in a Windows Help file with the software. FCC and program databases are updated through the company's website as often as desired. Program bug fixes, enhancements and upgrades are always posted for download. A subscription support service is available with FMCONT that gives the user telephone and e-mail support when needed. I have found V-soft Communications to be responsive, even when the problem was operator error or oversight.
With any allocation software a lot of time must be spent to achieve any level of expertise. Such software will not eliminate the need to use broadcast consulting engineers (although it is used by many such engineering firms).
Gluck is vice president of technical research for Salem Communications, Camarillo CA.
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