Keep in mind that most TIS stations are designed for short distance operation. Most TIS stations have a very minimal ground system that is mostly for static/lightning dissipation rather than for counterpoise purposes. I have inspected well over 100 TIS installations up close and only a couple had efficient ground systems. Most of the pole mount antennas have only a simple ground rod at the base of the pole. I have also inspected five TIS stations using the big Valcom antennas. Only one of them had an actual counterpoise. The two at D/FW Airport each had only a single chemically enhanced ground rod. Interestingly, the TIS stations with the best signals seem to be the roof mounted ones that either use an actual ground plane laid out on the roof, or the metal roof support beams, or an actual metal roof as the counterpoise. The presence of a counterpoise combined with the height of the roof mount units seems to give them superior coverage.
Patrick Griffith, Westminster CO Broadcast Technician NRC Broadcasting - Denver http://community.webtv.net/N0NNK/ http://community.webtv.net/AM-DXer/ _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
