Sunday 18 October 2020

'Metallic Bursts' at 24MHz.

The long-running debate about what 'metallic bursts' heard during summer on 50MHz could be took an interesting change of direction this morning.

The 24MHz band was right at the very edge of opening, where only one signal, OZ3BAM, was being heard at a fairly consistent level with my 3-ele beam pointed at 090 degrees. 

Other signals weakly coming in and out of reception seemed, for the most part, to be backscatter signals from EI and G stations, where they were sometimes decoded, but often not.

This is a brief recording of two FT8 cycles, where the first is a fairly steady level (the background hum is due to a lower-than-ideal input into HRD's recorder), and the second clearly has the bursts:


So the propagation appears to have been weak Es, with the structure lying to the east of me.  The propagation also seems to have been almost purely one-way, as I made many CQ calls, with no replies, and also that there were only a couple of reports via PSKreporter - although that doesn't always pick everything up, and can sometimes be delayed by several minutes in what it reports.

A large number of 'metallic bursts' were heard during a few minutes of listening.  This is not the case on other days, so the explanation that some angrily insist lies simply in meteor reflections, cannot reasonably be correct.  If it were, we would hear these 'pings' every day.

My idea has always been that these bursts are the result of transient propagation permitted by localised, rapidly-changing reflective structures in Es or Es-like patches.  I think this morning's experience only adds some credibility to that idea.

 




No comments: