Abstract
(Report on a completed Short-Term Scientific Mission (STSM) funded by EurAAP)
The ionosphere – under influence of the earth magnetic field – splits linearly polarized waves into two circularly polarized waves with opposite rotation sense [1]: magneto-ionic propagation. Our previous empirical NVIS research [2-4] has shown that that two orthogonal (physical) propagation channels can be created using dual circular polarization antennas, potentially doubling channel capacity. All previous measurements where performed on a 110 km long North-South path in The Netherlands (53ºN).
To prove that the concept is not limited to specific azimuth angles and distances, the following experiment was designed: Multiple (4-8) beacon transmitters are set-up at random azimuth angles and random distances between 50 and 200 km around a single receiver site, the transmitters operating at a frequency around 7 MHz. Each beacon switches between Right Hand Circular Polarization (RHCP), Left hand Circular Polarization (LHCP) and linear polarization every 12 seconds.
The signal of all beacons is recorded using a high-end digital receiver with 2 coherent antenna inputs, connected to two orthogonal dipoles. From this raw data, simultaneous reception of RHCP, LHCP and linear polarizations can be created. Isolation between the LHCP and RHCP channels will be calculated for each instant in time. The experiment is considered successful when more than 20 dB isolation is achieved. Possible improvement with adaptive elliptical polarization will be studied. Also the fading on the RHCP, LHCP and linearly polarized signals will be characterized and compared.
The vertical angle of the earth’s magnetic field – which depends on the latitude of the location – is of influence on the magneto-ionic propagation. To prove that the experiment latitude is not critical to our earlier results, the experiment is first performed in The Netherlands (53ºN), then duplicated in Spain (41ºN), with the assistance of experts of the La Salle Ramon Llull University of Barcelona. Travel and lodging costs for this cooperation are sponsored by the European Association on Antennas and Propagation (EurAAP) through their Short-Term Scientific Mission (STSM) program, which stimulates cooperation between propagation experts of different European countries.
The ionosphere – under influence of the earth magnetic field – splits linearly polarized waves into two circularly polarized waves with opposite rotation sense [1]: magneto-ionic propagation. Our previous empirical NVIS research [2-4] has shown that that two orthogonal (physical) propagation channels can be created using dual circular polarization antennas, potentially doubling channel capacity. All previous measurements where performed on a 110 km long North-South path in The Netherlands (53ºN).
To prove that the concept is not limited to specific azimuth angles and distances, the following experiment was designed: Multiple (4-8) beacon transmitters are set-up at random azimuth angles and random distances between 50 and 200 km around a single receiver site, the transmitters operating at a frequency around 7 MHz. Each beacon switches between Right Hand Circular Polarization (RHCP), Left hand Circular Polarization (LHCP) and linear polarization every 12 seconds.
The signal of all beacons is recorded using a high-end digital receiver with 2 coherent antenna inputs, connected to two orthogonal dipoles. From this raw data, simultaneous reception of RHCP, LHCP and linear polarizations can be created. Isolation between the LHCP and RHCP channels will be calculated for each instant in time. The experiment is considered successful when more than 20 dB isolation is achieved. Possible improvement with adaptive elliptical polarization will be studied. Also the fading on the RHCP, LHCP and linearly polarized signals will be characterized and compared.
The vertical angle of the earth’s magnetic field – which depends on the latitude of the location – is of influence on the magneto-ionic propagation. To prove that the experiment latitude is not critical to our earlier results, the experiment is first performed in The Netherlands (53ºN), then duplicated in Spain (41ºN), with the assistance of experts of the La Salle Ramon Llull University of Barcelona. Travel and lodging costs for this cooperation are sponsored by the European Association on Antennas and Propagation (EurAAP) through their Short-Term Scientific Mission (STSM) program, which stimulates cooperation between propagation experts of different European countries.
| Original language | English |
|---|---|
| Place of Publication | Enschede, The Netherlands |
| Publisher | University of Twente |
| Number of pages | 11 |
| Publication status | Published - 10 Mar 2016 |