Abstract: A communications device may include an RF device, and an antenna coupled to the RF device. The RF device may have a conductive ground plane, a conductive support rod carried by the conductive ground plane and extending outwardly therefrom, and a conductive body coupled to and surrounding the conductive support rod. The conductive body may have a helical slot to define a helical slot radiating antenna.

Abstract: A communications device may include an RF device, and an antenna coupled to the RF device. The antenna may have a conductive ground plane, a conductive support rod carried by the conductive ground plane and extending outwardly therefrom, and a conductive body coupled to and surrounding the conductive support rod. The conductive body has vertically spaced rhombus shaped slots therein to define a radiating antenna.

Abstract: A communications device includes an RF device, and an antenna coupled to the RF device. The antenna includes a conductive ground plane, an elongate support extending from the conductive ground plane, a helically wound conductive strip carried by a proximal end of the elongate support, and spaced apart conductive elements carried by a distal end of the elongate support to define an RF lens for the helically wound conductive strip.

Abstract: A communications device may include an RF device, and an antenna. The antenna may include a conductive ground plane, an elongate support extending from the conductive ground plane, and a helically wound conductive strip carried by the elongate support. The communications device may have a coaxial cable coupling the RF device and the antenna. The coaxial cable may include an inner conductor and an outer conductor surrounding the inner conductor. The outer conductor may be coupled to the conductive ground plane and the inner conductor may extend through the conductive ground plane and be coupled to a proximal end of the helically wound conductive strip.

Abstract: An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may include a ferromagnetic core and an H-field signal winding coupled to the ferromagnetic core. The eLORAN receiver may have an antenna tuning device including a tuning winding surrounding the ferromagnetic core, and a tuning circuit coupled to the tuning winding.

Abstract: An RF PNT system may include LORAN stations. Each LORAN station may include a LORAN antenna, and a LORAN transmitter coupled to the LORAN antenna and configured to transmit a series of LORAN PNT RF pulses having a time spacing between adjacent LORAN PNT RF pulses. One or more of the LORAN stations may include a message embedding generator coupled to the LORAN transmitter and configured to generate message RF bursts based upon an input message, and with each message RF burst being in the time spacing between respective adjacent LORAN PNT RF pulses.

Abstract: A communications device may include an RF device, and an antenna. The antenna may include a conductive ground plane, an elongate support extending from the conductive ground plane, and a helically wound conductive strip carried by the elongate support. The communications device may have a coaxial cable coupling the RF device and the antenna. The coaxial cable may include an inner conductor and an outer conductor surrounding the inner conductor. The outer conductor may be coupled to the conductive ground plane and the inner conductor may extend through the conductive ground plane and be coupled to a proximal end of the helically wound conductive strip.

Abstract: An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly from the ferromagnetic medial portion, a respective electrically conductive winding surrounding each of the ferromagnetic arms, and an electrically conductive patch element adjacent the ferromagnetic core.

Abstract: An antenna device may include a ground plane, a first planar antenna element spaced above the ground plane and having an opening, and a second planar antenna element spaced above the first planar antenna element on a side of the first planar antenna element opposite the ground plane. The second planar antenna element may have a size smaller than the first planar antenna element. The antenna device may include a coaxial feed with an outer conductor, and an inner conductor surrounded by the outer conductor and extending outwardly from an end of the outer conductor. The outer conductor may be coupled to the ground plane and the first planar antenna element. The inner conductor may extend through the opening in the first planar antenna element and may be coupled to the second planar antenna element.

Abstract: A communications device may include an RF device having an operating frequency range, and an antenna coupled to the RF device and being electrically small with respect to the operating frequency range of the RF device. The communications device may include an active capacitor coupled between the RF device and the antenna. The active capacitor may include a settable operating curve with a decreasing capacitance versus increasing frequency over a portion of the operating frequency range of the RF device. The communications device may further include a control circuit coupled to the active capacitor to set the settable operating curve.

Abstract: An antenna device may include a ground plane, a first planar antenna element spaced above the ground plane and having an opening, and a second planar antenna element spaced above the first planar antenna element on a side of the first planar antenna element opposite the ground plane. The second planar antenna element may have a size smaller than the first planar antenna element. The antenna device may include a coaxial feed with an outer conductor, and an inner conductor surrounded by the outer conductor and extending outwardly from an end of the outer conductor. The outer conductor may be coupled to the ground plane and the first planar antenna element. The inner conductor may extend through the opening in the first planar antenna element and may be coupled to the second planar antenna element.

Abstract: A signal-of-interest is received by using a first and second planar electrically conductive disc to define an antenna. The antenna produces RF signal outputs at three output ports Ex, Ey and Ez, each having a different associated gain pattern and polarization response. At least one null is automatically asserted in a pattern defined by the antenna in a specified direction by selectively weighting a gain and a phase of the RF signals respectively produced from the three output ports and then combining the RF signals to produce a first receiver signal output.

Abstract: A LORAN device may include a LORAN antenna, a LORAN receiver, an RF signal path extending between the LORAN antenna and the LORAN receiver and being subject to ambient RF interference, and an ambient RF interference canceller coupled in the RF signal path. The ambient RF interference canceller may include an ambient RF interference sensor configured to generate an estimated ambient RF interference signal based on the sensed ambient RF interference, and cancellation circuitry configured to cooperate with the ambient RF interference sensor to generate an ambient RF interference cancellation signal based upon the sensed ambient RF interference signal, and add the ambient RF interference cancellation signal to the RF signal path.

Abstract: A LORAN device may include a housing, and an electrically short LORAN antenna carried by the housing. The LORAN device may have a LORAN receiver carried by the housing and coupled to the electrically short LORAN antenna, and an RF crystal resonator coupled to the electrically short LORAN antenna so that the electrically short LORAN antenna is forced to a resonant condition for a LORAN receive signal.

Abstract: An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may include a ferromagnetic core and an H-field signal winding coupled to the ferromagnetic core. The eLORAN receiver may have an antenna tuning device including a tuning winding surrounding the ferromagnetic core, and a tuning circuit coupled to the tuning winding.

Abstract: An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly from the ferromagnetic medial portion, a respective electrically conductive winding surrounding each of the ferromagnetic arms, and an electrically conductive patch element adjacent the ferromagnetic core.

Abstract: A LORAN device may include a LORAN antenna, a LORAN receiver, an RF signal path extending between the LORAN antenna and the LORAN receiver and being subject to ambient RF interference, and an ambient RF interference canceller coupled in the RF signal path. The ambient RF interference canceller may include an ambient RF interference sensor configured to generate an estimated ambient RF interference signal based on the sensed ambient RF interference, and cancellation circuitry configured to cooperate with the ambient RF interference sensor to generate an ambient RF interference cancellation signal based upon the sensed ambient RF interference signal, and add the ambient RF interference cancellation signal to the RF signal path.

Abstract: An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly, and a respective electrically conductive layer surrounding each of the ferromagnetic arms and having a slot.

Abstract: An RF PNT system may include LORAN stations. Each LORAN station may include a LORAN antenna, and a LORAN transmitter coupled to the LORAN antenna and configured to transmit a series of LORAN PNT RF pulses having a time spacing between adjacent LORAN PNT RF pulses. One or more of the LORAN stations may include a message embedding generator coupled to the LORAN transmitter and configured to generate message RF bursts based upon an input message, and with each message RF burst being in the time spacing between respective adjacent LORAN PNT RF pulses.

Abstract: A LORAN device may include a housing, and an electrically short LORAN antenna carried by the housing. The LORAN device may have a LORAN receiver carried by the housing and coupled to the electrically short LORAN antenna, and an RF crystal resonator coupled to the electrically short LORAN antenna so that the electrically short LORAN antenna is forced to a resonant condition for a LORAN receive signal.