| 摘要 |
A dual function antenna system and method. A system is provided for using a single antenna for both the reception of low frequency navigational signals, such as LORAN-C, and high frequency communications signals in the VHF region. The antenna is at a remote location from a low frequency receiver and a high frequency transceiver. Both the low frequency and the high frequency signals are coupled to the receiver and transceiver, respectively, over the same transmission line at one end thereof. A preamplifier is provided at the location of the antenna to increase the strength of the low frequency signal applied to the transmission line. A high pass filter is provided to couple the antenna and the transmission line and prevent feedback from the output of the preamplifier from reaching its input. The other end of the transmission line is coupled to the high frequency transceiver by a high pass filter, and to the low frequency receiver by a low pass filter. The preamplifier is supplied with DC power over the transmission line, and includes a current regulator so that the preamplifier may be used with a wide range of supply voltages.
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