TopBand: Fwd: echo boundary="part0_890429296_boundary"

[Robert Brown]

Jeff,

Thanks for re-posting Kevin's log.  I have looked through it and the main 
impression I come away with is that the two-mode ducting was in effect in 
the ionosphere from 1014Z when he worked VE1ZZ to about 1100Z, ending by 
the time he worked WV3B.  And by the looks of it, the greatest problems 
with the multi-pathing was for stations close to their sunrise.

Now Kevin revives the long-path idea and let me shoot that in the head, 
once and for all.  All you have to do is look at all the sunlight on that 
path with your mapping program and you will know there is just NO WAY 
that a 160 meter signal could survive.  So let's just leave that idea 
lie where it is.  It will get us nowhere.

Now I am not an "antenna person" so I will defer to the experts on that 
but I do know that beam or phased antennas have back lobes and they 
can be non-trivial in their effects.  Who hasn't worked some DX off the 
back of his/her beam?  So when you say you think it is long-path to the 
SE, not short-path to the NW, I immediately think of a back lobe.  And 
when you say the signal went UP in strength, I think it must be a BIG 
back lobe.  And when you say "sunrise", I think of high angles, making 
that back lobe a high one.  

Now with one last item, I will relax and wait for the NEC experts to 
weigh in; if you RECEIVE well on a lobe, front or back, you will TRANSMIT 
well on it too.  So I am still not surprised by Kevin's report about your 
signal; it is consistent with the back lobe idea.  But the NEC guys can 
work this over.

I really don't think much of side-scatter by the ionosphere as a possible 
explanation but Rob, K2WI, suggested some sort of ground reflection.  Now 
reflection off of ground is much more efficient so signal-wise, that may 
be a possibility.  It would then depend on the slope and orientation of 
the hillside, mountain or whatever.  I am a Westerner, through and 
through, and I really don't know what your geology is like.  The only 
thing I can say at this point is that for ground reflections to be the 
answer to your problem, it would be some sort of mountain range or 
whatever to the southwest of you.  Any reaction to that?

OK, I am poised and ready to see what other reactions that set of QSOs 
brings forth.  "Gentlemen, man your keyboards!"

73,

Bob, NM7M



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