b'ASEG newsCommitteesProgress in 2023TechnicalOver the past year, 50% of workload has been dedicated to making instrumentational improvements to the MAPRad device. The antenna design has been modified, with the number of coil turns around the magnetic core being kept the same, while changing the core length has been experimented with to determine how large an effect this has on the radars overall performance. This was briefly tested during a field test in the You Yangs, Victoria, but needs to be looked at further.While the magnetic antenna itself has undergone minimal modifications, the electronics that the antenna feed into have undergone significant changes. The receiver antenna amplifier has been the focus of the project work, updating a previous amplifier schematic to use a four-stage amplification process before being fed through to the receiver for capture. The design consists of two channels, to provide differential signal amplification, with each channel containing four stages of approximately 15.8 dB of gain for a total of 63.2 dB gain across the entire amplifier board in each channel. Much consideration has been given to oscillations within the board and noise pickup from external sources, as such shielding and appropriate circuit design has been added to the circuit board to isolate and protect each channel Figure 3. Neural network predictive dome potential. from rogue signals. The PCB has gone through two major design changes thus far, as a result of initial lab testing before area can be expanded to a regional scalethe current design. The software Altium rapidly, and at a low computational cost.RF22E01 RMIT University, PhD Studentis being used for designing the amplifier The model can be used as a quantitativeMatthew Auld (Supervisor Dr Gail Iles) (Figure 1a) and the actual PCB has basis for potential field confidence asIn-situ physical property measurementsalready been printed (Figure 1b).an element of a mineralisation potentialwith a novel multispectral, multistatic model, for example, by compositingground penetrating radar. The manufactured amplifier has been additional data about structural featurestested in a lab setting to verify operation and mineral occurrences. across the designed range of frequencies, Summary up to 30 MHz. Gain and phase linearity of This project was finalised as a mastersthe amplifier have been measured and thesis and submitted at the end 2023.Matthew is investigating the requiredhas shown that the amplifier operates The research has also been presented atmethodology to extract meaningfulwell within the lab and operating AEGC 23 with the support of the ASEGphysical properties from Ground andconditions. Real world testing is planned research grant, and as a poster at the AIGLunar Penetrating Radar surveys.for the next few months to determine OREAS Victorian Minerals Roundup. ItsThe project utilises ultra-sensitiveif the new amplifier is performing as been a great project to see me throughmagnetic radar (MAPRad) sensorsexpected when used in tandem with my post-graduate study, and Im gratefuland transmitters developed at RMITthe other components of the system in to the ASEG for funding the project withUniversity, small enough to be installedthefield.a research grant, my project supervisoron autonomous rover platforms. With Mark McLean, North Stawell Minerals andthe use of multispectral, multi-staticTrainingBill Reid for approving and supportingdata, the project aims to deliver software the fieldwork and modelling, and Markfor survey geometrical design and theIn September 2022, Matthew attended Grujic from Datarock for mentoring theextraction of accurate layer radar waveThe Camp for Applied Geophysics machine learning component. velocity, attenuation and thickness.Excellence (CAGE) which provided insight FEBRUARY 2024PREVIEW 13'