I4JMY and N4GN wrote
> Is there anyone who has or knows some theory about ?
My humble guess (and I'd love to hear the experts' opinions) is that there
was some coupling between F2 and sporadic-E hops. Maybe even some strange
chordal hops. >>
No official propagation expert here, but way back in the 70s and 80s, when I
used my stacked VE3BMV Razor Beams (Quad-Yagi combination) I have observed
numerous anomalies that didn't jive with conventional "Reflective" Propagation
Theory. There was a number of unconventional openings, including long delayed
echoes observed. Having very potent antenna system, I was reinforced in
conclusion that we are not only reflecting or bouncing signals between the
Ionosphere and ground, but also ducting (in the layers).
My experiences were summarized in an article published in CQ Magazine and
Radiosporting. (I will have them and more on the home page real soon now.)
Just a note that I received comments, some saying no way, some saying this
is nothing new. Go figure.
I recommend reading that article, think about it, keep yours eyes and ears
open, make notes and we will keep thread about it on the home page for the
benefit of others, esp. newcomers. Let's not forget the stuff OFs lived
through.
Just a thought for a nay sayers:
Isn't it true that the lower the frequency, the more refraction - bending
possible? VHF operators know about ducting.
My first rule of antenna design is: Antenna radiation pattern has to fit the
prevailing propagation modes/angles. (We often see people chasing low angle,
because "its better for DX", when it ain't so!)
Another finding from my stacked Razor Beam era is that best vertical receive
angle is not always the same as best transmit angle, I found more times
disagreement than agreement.
One more thing for upswing in sunspots: with higher sunspots, the propagation
angles get generaly higher (atmosphere/ionosphere expands). Time for even low
wire antennas to be heard.
10m is the other extreme HF fun (challenge) to 160m band.
Thanks for contest points in 97, MX and HNY 98 to all!
Yuri Blanarovich, VE3BMV, K3BU, P40A etc.
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