Quadrantid radio detection

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Colin Briden

Hi Alex

I monitored the Quadrantids on 200103-5 by forward scatter using the BRAMS beacon. From here it has a bearing of 137 deg. and range 600km.

The attached chart for Jan 03 shows a gentle rise after 2200 as the radiant climbed in the NE sky. The chart for the following 24h period of Jan 04 shows an odd drop in numbers between 0045 – 0145 followed by a steep rise from 0200 when the azimuth of the radiant was at around 47 deg – meaning that a high proportion of ionised trails lay normal to the line between transmitter and receiver, the ideal situation. Numbers held to a steady maximum centred on around 0400 before declining after 0515 to a low at about 0800 – when the azimuths of the radiant and BRAMS temporarily coincided, leading to a reduction in detected events. Then numbers slowly increased again to a second but slightly lower peak at around 1320. There was an abrupt drop at 1330 and by 2030 the radiant was on the northern horizon at an altitude of about 12 deg. Meteor numbers were then very low… they were probably mostly sporadics. The following morning to 1200 showed only comparatively low levels of activity in a normal diurnal curve.

At the time predicted for the visual maximum by the Nemetode analysis (0445) levels are certainly high. On the other hand the IMO predicted a short-lived maximum on Jan 04 at 0820 and the BAA on Jan 04 at 0900. Perhaps the rise and fall of a radio maximum at around 0830 was detected here – but the peak was lost to the ‘hollowing-out’ of the curve caused by the null detection point falling at the same time. This would be a long maximum, abruptly ended.

In all this I haven’t taken account of the changing altitude of the radiant as the maths is a bit complicated. I will have to think about that one!