Gpredict is a real time satellite tracking and orbit prediction program. Besides the general orbital data for satellites, gpredict can also calculate the footprint, visibility, doppler shift, signal loss, and signal delay for each satellite relative to one or more ground stations. The calculated data can be viewed in tables, on maps, or on polar graphs.
linSmith is a Smith charting program. Users can enter either discrete components or transmission lines, see the results on screen, and/or generate Postscript output. Component values can be changed numerically or using scrollbars. Problems can be solved on-screen, and high-quality Postscript can be output for publication.