Topband: 160 Meter Propagation

[Larry Molitor]

Bob,

Thanks for clearing up the low latitude ducting question. You're right, I 
let the low latitude aspect get completely past me when I asked the 
question. You're explanation clears up a lot of the  east/west path 
uncertainties I've had.

However, you (and maybe W4ZV) are going to have to work a lot harder to get 
me to believe the difference between JA and EU from this QTH can be 
completely explained by auroral effects.

I am assuming the "auroral zone" can be defined by the satellite images 
depicting auroral activity and intensity. Perhaps that assumption is 
incorrect. If it is correct, then it's hard for me to accept that the 
minimal or close miss passage of signals through the zone from central and 
southern EU would account for the 30+ dB of difference in path loss I see 
compared to the JA path.

I'll buy the concept for Scandinavia, that's a given. When I hear those 
guys on, the signals always have an aurora signature and I never hear them 
at the same time as the other EU stations. Eastern EU and middle east have 
never been heard by me at this QTH. Those are truly polar paths and, baring 
divine intervention, I will never hear them with the RX conditions I have 
here.

If I can hear DL, I can hear EA, I, G, etc. The GCB from me to EA is 
47°/8970 km., clearly south of what I consider the auroral zone on a quiet 
night, and little different than the path to JA. If a few degrees make that 
much difference, why don't I see it between DL (34°) and EA(47°)?

On a slightly different note, I listened for 9V1PC for 90 minutes prior to 
my sunrise this morning. There was no detectable signal during that time 
with the RX antenna swept from 250° through 315°. GCB from me to 9V is 
310°. KC7V, 40+ miles north of me, did copy him at 449, but Mike's noise 
floor is many dB lower than mine. JA's were loud and easily worked (310°) 
up until 60 minutes before my sunrise when they disappeared. Did they all 
go to bed or did prop go sour?

73,

Larry - W7IUV




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