Magnetospheric line radiation (MLR) events are relatively narrowband VLF si
gnals (similar to 30 Hz) that sometimes drift in frequency and that have be
en observed in both ground-based and satellite data sets. We present the re
sult of a survey undertaken on the basis of measurements made of MLR events
observed at Halley station, Antarctica (75 degrees 35'S, 26 degrees 33'W,
L approximate to 4.3) during June, July, September, and December 1995, spec
ifically to examine whether there is a link between MLR and power line harm
onic radiation (PLHR). We find that (1) the diurnal variation of MLR occurr
ence at Halley does not resemble the expected load pattern in the industria
lized conjugate hemisphere; (2) MLR does not show the pronounced east-west
asymmetry in the distribution of arrival directions which would be the case
if it was linked ro North American electrical load; (3) MLR does not show
an immediate association with geomagnetic activity, as would be expected fr
om increases in PLHR levels produced by geomagnetically-induced currents sa
turating transformers; and (4) there is no evidence of a Sunday, weekend, o
r other 7-day cycle in the occurrence of MLR. Taken together these results
strongly suggest that MLR is a natural VLF emission and is not primarily ca
used by PLHR. In addition, Halley data have been examined to determine whet
her the intensity of all types of VLF emissions are influenced by PLHR. We
find that (1) there is no significant difference between weekdays and weeke
nds over the frequency range 0.5-9.3 kHz and (2) there is no consistent cha
nge in wave intensity that is observed around any of the major North Americ
an holiday periods. It is concluded that PLHR is not a significant influenc
e on geospace as viewed from Halley.