Quadripole Antenna System

Dual (orthogonal) Short Dipoles and preamplifier assembly:

The Quadripole antenna system consists of a pair of  .01 to 30 MHz receive-only active antennas mounted at right angles to each other. It is fed power by way of a single CAT5 cable which also returns RF from each antenna/preamp differentially to v2 ShackBoard  which provides single ended outputs to a receiver.

When combined with a dual ADC  vector LF-HF SDR,  either analog or DSP techniques may be used to synthesize wave polarization and to provide antenna beam forming. Because most if not all ionospheric propagation involves RHCP and OHCP propagation, O and X waves, these two may be separated, measured and managed separately.  In this manner., constructive and destructive wave interference in the polarization domain may be used to advantage for study and for improved communications over the entire LF-HF range

Existing dual-ADC SDRs such as those provided by Anan, Flex, Red Pitaya, TRXduo and others combined with appropriate supporting DSP software can  receive, manipulate and be used with this system. A 'strawman' description of a complimentary, 2 channel vector SDR receiving system supporting  this dual channel application along with the potential for very high channel matching calibration is available.

The  dipoles are mounted on a PVC housing which contains very high impedance preamplifiers connected to each of the four monopoles and produces opposing pairs of outputs which are followed by a high dynamic range broadband differential amplifier having fixed gain.  Each differential output drives one pair of the CAT5 cable where it is conveyed to the receiver location, received in hardware and possibly combined to synthesize polarization or provide beam forming, noise rejection and whatever else may be useful.  This synthesis and combination may also be done more flexibly and precisely using a dual-channel vector SDR and digital signal processing.

Closer view of the Quadripole v2 preamplifier

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