Hi Roelof,

Thanks, most interesting!

73, Stefan

Am 03.10.2013 20:00, schrieb Roelof Bakker:

Hello Stefan,

I study propagation of Canadian NDB's in the range 200 - 520 kHz by means of a PERSEUS spectrum recoding from 200 - 600 kHz. This recording runs every night.

The Kyoto Dst has been well above zero for the last couple of weeks and peaked at 41 on 03:00 UTC on October 2.

It than made a steep dive and bottomed up at just below -40 at 11:00 UTC.

It was found that propagation from Canada ceased completely over the 200 - 500 kHz frequency range, starting at 03:00 UTC on October 2. This is way before the Dst passed the critical level of -20 which has been found before.

I gather that the speed of the change is related to the sudden drop out.

It was if someone had pulled a switch!

73,
Roelof, pa0rdt