The data of an early report tentatively linking the radial orientation of the interplanetary magnetic field (IMF), measured by Explorer 35, with ULF activity in the Pc 3--4 range observed at Calgary in September 1969 have been supplemented by data from October and November 1969. The larger sample of hourly values confirms the results discerned before: (1) there is a contribution to Pc 3 and 4 signal amplitudes that disregards the conventional separation between the bands at T=45 s; (2) the contribution is apparent under quiet conditions when Kp?2o; (3) the contribution comes from signals whose probable amplitude is highest when the field is along the sun-earth line and lowest, essentially at instrument threshold, when the angle ϑXB between X (GSE) and B (the IMF) exceeds about 60¿; (4) the trend of high signal amplitude with low ϑXB is replaced by cos ϑXB, suggesting a propagation property of waves in the solar wind; and (5) the trend and its properties are compatible with, although not compelled by, a model of signal origin in quais-parallel bow shock structure.