VLF: Broadband goniometer receiver
Broadband goniometer receiver

A VLF goniometer (direction-finding) receiver, essentially similar to that described by Bullough and Sagredo (1973) but see also Smith et al. (1979), is operated on a synoptic basis. The two broadband signals from the north-south and east-west channels of the preamplifier/aerial loops are recorded on the two channels of digital audio tape (DAT), with a bandwidth up to 22 kHz and dynamic range of about 90 dB. Recordings are normally made for 1 minute every 15 minutes (05-06, 20-21, 35-36, and 50-51 minutes past the hour). At times of unusual activity or for special campaigns, alternative schedules of 1 minute recording every five minutes, or of continuous recording, can be run. A time code (IRIG-B) is also recorded on the tape. Control of the tape recorders is through the AVDAS (Advanced VLF Data Acquisition System) (Smith et al. 1994). The data tapes are analysed using the interactive spectral display provided by the AVDAS. The arrival azimuth can be determined from the relative amplitude and phase of the north-south and east-west spectra.

Examples of data   VLF Summary Plots   Data access

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