Hi Colin,
That’s a really nice set of radio data. During that time there is only a low level of activity from minor showers, and the ever-present sporadics, so we can assume the plots give a good approximation of Quadrantid rates.
The NEMETODE peak of 04:45 UT was derived from combining several years’ data and the individual years will have profiles that are affected by sub-peaks, brief drops in meteor flux, etc. The peaks suggested by the IMO and the BAA Handbook Meteor Diary were based on slightly later solar longitudes. The maxima derived from visual, video, radio and professional radar systems can differ in time because they can be detecting meteors from different sized meteoroid bodies and particle-sorting takes place in the stream, etc.
In some cases a bright meteor seen visually won’t have been detected on radio, and a very good radio trace wasn’t picked up by video cameras. I guess these are examples of optimal / non-optimal radio detection alignments.
We had awful conditions for visual and video work this week, so I’ll ask our radio observers to have a look at your extensive coverage.
I’m surprised we aren’t a nation of radio astronomers.
Alex.