Hi Alan,

That is an interesting comment. In my years DXing on 1.8 MHz I
notice something similar. Quite consistently when Kp is very low for
several days, propagation becomes poor (with the possible exception
of the polar path around solar minimum). Signals tend to be much
better when Kp is 3 or 4. Often there is a strong upsurge in signal
strength when Kp begins to rise following several days of being very
low. This can easily be 20 to 30 dB, perhaps even more. Timing of
the upswing is interesting, however. Sometimes it occurs when Kp
starts upward, sometimes hours before. It seems quite consistent,
however, that a sustained period of very low Kp is not good. With
far less experience to go on, I believe I have noted this phenomenon
at 475 and 137 kHz as well.

73,
Paul N1BUG


On 11/3/18 5:48 PM, Alan Melia wrote:
> Hi Roelof, I am not actively following day-by-day reports these days, but I 
> do remember a condition in one of the last Solar minimum where after a long 
> geomagnetically quiet period signals seemed to be depressed. I postulated 
> that maybe the ionisation of the E-region was not only dependent on cosmic 
> rays but maybe had a charge input from the Solar wind. After a 30 day period 
> with Kp continualy below 3 we had a Kp=4 coronal hole flow event and 
> propagation immediately improved again. I wondered, but could not find any 
> supporting evidence, whether the ionosphere could ''weaken'' and leak 
> signals into space leading to weaker reception.
> 
> Just a wild idea but maybe worth checking against dates and geomagnetic 
> activity.
> 
> Alan
> G3NYK
> 
> ----- Original Message ----- 
> From: "Roelof Bakker" <[email protected]>
> To: <[email protected]>
> Sent: Saturday, November 03, 2018 4:16 PM
> Subject: Re: LF: WSPR 475 kHz
> 
> 
> Mike,
> 
> Don´t underestimate the power of propagation.
> 
> NDB´s from Canada and also MW broadcast stations have been much stronger 
> than I have seen for
> years. Also the number of decodes of Canadian DGPS stations has been 
> dramatically improved.
> 
> The signal of VO1NA on 137.777 kHz produces audio copy here.
> 
> 73,
> Roelof Bakker, pa0rdt