Coverage Analysis with Open Source Tools

Part 7 - IEEE Broadcast Technology: Winter 2016-2017

Generating Antenna Relative Field Plots and Tables from TVStudy

URLs referred to in the article:

November 2015 CDBS Extracts
Links for Fall 2016 COverage Analysis with Open Source Tools aritlce

Creating Field Strength Maps with QGIS

My Winter 2016-2017 IEEE Broadcast Technology Society magazine article describes how QGIS can be used to display the output from the FCC's TVStudy program as cells with different colors for different levels of predicted field strength. For information on how to install and run QGIS, see the links I posted for Part 6 of Coverage Analysis with Open Source Tools - Mapping data with QGIS. See the link above. In order to plot a map showing coverage with interference, it is necessary to combine the TVStudy D_CelData.csv and U_CelData.csv files. My "coverage_to_csv" Python program does this and also changes the west longitude from a postive to a negative number to avoid having the data pop up half-way around the world. The program, sample data, and QGIS style files are available for download below. 

Generating Antenna Relative Field Plots and Tables from TVStudy

I'm continuing work on my "tvstudy_IX_analysis" Python program. In my Winter 2016-2017 BTS magazine article I described its current status. This Python program, when run in the root directory of the TVStudy interference check output results for the study of interest, will use data from the tvstudy.txt file to identify stations receiving interference over the de-minis level and calculate the required reduction in ERP to remove interference, starting with the cells closest to the threshold (least power reduction required) and continuing until the interference population drops below the de-minis level. This process is repeated for all victim stations receiving interference above the de-minimus level. The antenna azimuth where the reduction is required is round to the nearest degree, the ERP reduction required to meet all interference cases on that bearing is then calculated, converted to relative field, and plotted as the required antenna pattern. To create a more useful antenna pattern, the reduction is also calculated at five and ten degree intervals and plotted. A csv antenna pattern file suitable for import into TVStudy is created for the required patterns.

Future work involves changing the de-minimis interference threshold from 0.5% to 2.0% when the victim station is identified as an LPTV or translator station. The function used to determine the ERP reduction required accepts different threshold values, so adding this shouldn't be too difficult. Different thresholds may also be required for different stations during the repack after the incentive auction.

While not mentioned in the article, the module must be installed to allow the program to calculate the bearing from the antenna to the cell receiving interference. I eventually I plan to replace this with a function that duplicates the bearing formula used in TVStudy. Any help here would be appreciated! The module is available at:

The files referenced in the article are available from my website in the directories listed:

Questions, additions or comments?

Contact Doug Lung at

Last modified 23 December, 2016