OET Updates TVStudy Software
Last Friday the FCC Office of Engineering and Technology released an update to the “TVStudy” software that it is considering for use in the incentive auction repacking to do the OET-69 coverage and interference analysis required by Congress's Spectrum Act.
The propagation model used for the analysis hasn't changed—it’s the same code (with the same bugs) as used for the DTV transition. What has changed is how the TVStudy program handles the “cells” when counting coverage and interference. David Fort from Daystar discovered a problem when he tried to study station WYDN's coverage. A single station coverage of WYDN using the Global Grid type caused the TVStudy program to crash both in Windows and Linux.
The new release includes a pre-compiled 64-bit Linux version of TVStudy. The Linux TVStudy readme file instructions assume a clean installation of Ubuntu 12.04.2.
I found the compiled TVStudy ran fine using the Manjaro, which is based on Arch Linux, using the MariaDB SQL server and client libraries version 5.5.30-2 instead of MySQL.
If you followed the instructions in my April RF Technology column all you will need to do to use the latest software is to copy the files from the TVStudy software (Linux) compressed file into your existing installation. Use the provided tvstudy and tvstudy.jar files.
If you want to compile the new version, the FCC Readme has information on how to install on Ubuntu. If you’re using Arch or another distribution you may have to change the paths in the Makefile or use my modified Makefile. I found the new tvstudy.h file worked without modification.
As noted, the itsitm.f FORTRAN code used to calculate Longley-Rice coverage has not changed. The TVStudy program offers more options for determining the parameters used for the study. There will be small differences if the old OET-69 parameters are used, but they shouldn't be significant. However, if the parameters are changed, the impact is significant and not always to the benefit of broadcasters.
As an example, using the original “Effective height” method, rather than the new “True geometry” option as the Depression angle method helps reduce the errors introduced by using the default FCC elevation patterns, especially for mountain-top sites.
Look for more tips on using TVStudy in my next RF Technology column.
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Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.