Total posts : 45366
[quote=radio8z]I also notice that the TIS stations in this area use center loaded designs.[/quote]This is a little odd, because the FCC limits the field strength of TIS stations, among other things (see paste below). So it wouldn’t seem really necessary to squeeze the last bit of efficiency out of the antenna system.
From Part 90.242:
(4) For a station employing a conventional radiating antenna(s) (ex.
vertical monopole, directional array) the following restrictions apply:
(i) The antenna height above ground level shall not exceed 15.0 meters (49.2 feet).
(ii) Only vertical polarization of antennas shall be permitted.
(iii) Transmitter RF output power shall not exceed 10 watts to enable the user to comply with the specified field strength limit.
(iv) The field strength of the emission on the operating frequency shall not exceed 2 mV/m when measured with a standard field strength meter at a distance of 1.50 km (0.93 miles) from the transmitting antenna system.