AM Band Antenna Array

Studying the D-Layer of the Ionosphere is difficult due to the low plasma density that tends to occur at the bottom of the Ionosphere, necessitating relatively low frequency signals in order to probe the overhead conditions. Ionosondes, the sensors typically used to probe the Ionosphere, mostly bottom out at 1MHz and, due to the need to operate across a wide bandwidth, their antennas are very insensitive at those frequencies. My goal is to build a passive collection system utilizing local MF stations (i.e. WDAO at 1.21MHz) as transmitters to collect long-term data on ionospheric conditions in the D- and bottom of the E-layer. The problem is twofold: 1) the reflection path is expected to be HIGHLY lossy so there will be a strong direct path signal and a weak reflection path signal of interest 2) the extremely low frequency of the signals necessary make miniaturizing the antenna system difficult, especially if (as expected) we will need to operate across multiple stations and frequencies over the course of the day. My current plan is to set up an array of ~5x crossed wire-wrapped ferrite loop antennas as elements in conjunction with a variable capacitor to tune. Co-sponsored by: Wright-Patt Multi-Intelligence Development Consortium (WPMDC), The DOD & DOE Communities Speaker(s): Dan Agenda: Studying the D-Layer of the Ionosphere is difficult due to the low plasma density that tends to occur at the bottom of the Ionosphere, necessitating relatively low frequency signals in order to probe the overhead conditions. Ionosondes, the sensors typically used to probe the Ionosphere, mostly bottom out at 1MHz and, due to the need to operate across a wide bandwidth, their antennas are very insensitive at those frequencies. My goal is to build a passive collection system utilizing local MF stations (i.e. WDAO at 1.21MHz) as transmitters to collect long-term data on ionospheric conditions in the D- and bottom of the E-layer. The problem is twofold: 1) the reflection path is expected to be HIGHLY lossy so there will be a strong direct path signal and a weak reflection path signal of interest 2) the extremely low frequency of the signals necessary make miniaturizing the antenna system difficult, especially if (as expected) we will need to operate across multiple stations and frequencies over the course of the day. My current plan is to set up an array of ~5x crossed wire-wrapped ferrite loop antennas as elements in conjunction with a variable capacitor to tune. Virtual: https://events.vtools.ieee.org/m/437436