Development of VHF LC-Passive Filters for Multiband Transient Radio Telescope

Abstract

Filter is one of key module in a radio telescope system. This article present the development of VHF LC-passive filters meant to support a multiband antenna in a transient radio telescope system by reducing the bandwidth of each operating frequencies. The filters were developed by employing low-cost inductor and capacitor with low self-resonant frequency (SRF) and hence the characteristic are highly affected by the parasitic inductance of the capacitors and parasitic capacitance of the inductors. Therefore, general equation to develop an LC filters was no longer applicable in developing these filters. Nevertheless, three filters were successfully developed, operated at 38 MHz, 74 MHz and 152 MHz with relatively good quality factors up to of about 13. AcknowledgmentThe authors would like to thank Universiti Kebangsaan Malaysia for sponsoring this work.

Characterization of the South Atlantic Anomaly

“…There are some characteristics that should be addressed regarding this work (Anwar et al, 2017). The abnormally large amplitude of the horizontal geomagnetic field component measured at the magnetic Equator is caused by the intense current flowing in the equatorial ionosphere (Hamid et al, 2013).…”

“…But there still exists a region where the Earth's magnetic field is the weakest: this region is known as the South Atlantic Anomaly (SAA). The region arises due to the offset of the Earth's dipole of about 436 km from the Earth's center towards the direction of southeast Asia (Asikainen and Mursula, 2008).…”