[UK-CONTEST] 40m to USA long after sunrise

[Clive Whelan]

This is getting a bit OT- contest but hopefully you might be interested.


Further to the below, I continued to listen to N8AA as he worked a 
string of JA and UA0 stations most of whom were audible here. As the 
clock ticked around to 11:15z his signal had audibly dropped, and by 
11:30z he was down to 339. I expected this to continue, and indeed it 
did reaching 229 between 11:35 and 11:40z. What I did not expect however 
was that the signal would then climb significantly before local noon, 
and by 11:50 he was back up to 559. This fall and rise was quite steady 
and consistent, and whilst this could have been due a random variation 
in propagation it didn't sound like that to this- not 
inexperienced-observer.

During this period he was called and worked UA1, UA3, UA9, and OH but an 
OZ who was obviously hearing him quite well did not get a reply. Clearly 
in this situation the more Northerly latitudes were significantly 
favoured, which tends to confirm a skew path in the polar region.

However a dip in signal about 20 minutes before local noon didn't seem 
to make any sense to me. When I looked at the W8-JA path on a globe I 
see that it runs well to the Pacific side of the North pole. What the 
significance of this is I'm not sure, but I was then given to consider 
that the polar region might be in virtually continuous sunshine at this 
time of year, and perhaps the "early" peak in absorption might indicate 
an effective refraction point somewhere on a line of longitude about 5 
degrees East of this QTH ( 20 minutes is roughly equivalent to 5 degrees 
of longitude I think?). More questions than answers, but I hope I'm not 
alone in being fascinated by such phenomena.

Sadly by 11:55 the run of JA/UA0 seemed to dry up, or perhaps N8AA had 
to QRT for work, but I didn't hear him again.

73

Clive
GW3NJW

Clive Whelan wrote:
> Not at all unusual, in fact quite common at this time of year, 
> especially in sunspot minima with low flux and consequently low 
> absorption. There is little doubt that the F layer will support 7Mhz 
> refraction at virtually any flux level, and the limiting factor is 
> absorption at lower levels, as well as geomagnetic disturbance, also low 
> in sunspot minima.
>
> As I write- 11z in brilliant autumn sunshine- I am hearing N8AA in Ohio 
> at 569. Sure he is running 1Kw and a 2el, but he is working JA and UA0 
> (both of which are audible here) so he's not beaming this way. It's 
> clear that the path is not "normal" as one can hear polar flutter which 
> would not be normal on a W8. Whether this is a significant enhancement 
> is not clear however.
>
> It is clear that absorption is exceptionally low as I feel like I have 
> to crank the audio gain right up, so quiet is the rx. As it happens the 
> QRN level is also exceptionally low. It won't be long before the West 
> coast is audible on the long path in mid to late afternoon, and so NA 
> will be workable though most of 24 hours.
>
> I'm just using a Butternut here.
>
> 73
>
>
>
> Clive
> GW3NJW
>
>
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