Re: [IRCA] Excellent cx to the north

[Russ Edmunds <wb2bjh@xxxxxxxxx>]

--- Bob Foxworth <rfoxwor1@xxxxxxxxxxxxxxx> wrote:

> Nelson believed in path skewing. I recall that he called it a "tilt
> mode"
> and the idea was that normally the reflecting "surface" in the
> ionosphere was a virtual plane that was parallel to the earth
> surface.
> The signal path would then travel in a straight line from tx to rx.
> When the "tilt mode" occurred, the virtual surface would be tilted
> at some right angle to the path of the signal, so the signal
> reflection
> would occur at some angle relative to the physical path between
> tx and rx. These tilt modes would allow signals to "bend" around
> the auroral oval as they crossed polar regions and escape the
> absorption from the aurora.

**** I think you may be confusing two of Nelson's ideas. He did indeed
believe in skewing, but his 'tilt mode' was something different. It was
based on some tropical band experiences reported by others where under
certain conditions, it was believed that the ionosphere itself
developed tilts at or near the terminator ( this making this
potentially collateral with grayline receptions ). The concept of
ionospheric tilts had not at the time ( and perhaps hasn't yet ) been
by any means accepted in the scientificv literature as anything more
than a hypothesis. 

This was also related to another of Nelson's theories of 'chordal mode'
which relied on ionospheric tilts to cause the signal to deviate from
several bounces along the way by going up from transmitter to the
ioniosphere, encountering a tilt, then crossing several thousand miles
to encounter a similar but opposite tilt in the ionosphere whjich would
then return the signal to earth. Presumably this would reduce the
losses
of multiple hops, and also presented a potential way to avoid
absorption in the auroral zone. This theory was dependent upon a couple
of cases reported again on SW, and required ( IMHO ) entirely too many
things to align 'just so' to occur. 

There was actually some scientific corroboration for the idea of
skewing of a sigal in the polar regions, suggesting the origin was due
to a combination of the magnetic fields nearer to pole, and also
glancing off the absorption zone itself. 

Also, as I now type this in the shack, with a GC map on the wall, the
path for the receptions by myself and the late Page Taylor would have
been a shade under 350 degrees.



> 
> There is also a "chordal" mode where the tilt would occur in
> the same direction as the signal path, so the signal would hop
> at a tangent into space, and not back to earth (for the first hop)
> and when you had a reverse tilt at the other end of the chord, the
> signal became a "one hop" over several thousand miles, and
> arrived a lot stronger than it would be if it hopped normally. But
> the path track over the earth was a straight line. These are
> really uncommon.
> 
> The Xinjiang (then, it was Sinkiang) receptions on 1525 on the ECNA
> were all, to my knowledge, made in December-January around 2200z.
> The first ones I can remember were in 1965. My best one was in
> late fall 1972 at 2200z. Russ Edmunds had telephoned me to tip
> me off about it. I don't think these were greyline. As others have
> reported, this was due to a reported 2 megawatts and a big DA
> blasting RF into the european Soviet Union, and directly over to
> the US. I think the North Koreans could be considered greyline,
> as the path skims along near the sunrise terminator.
> 
> I guess I heard Xinjiang a half dozen times with some sort of
> copiable signal. I lived very close to WTHE-1520 and remember
> having to call them, after their sign-off, to kill their exciter,
> which
> was pretty loud for me, so I could hear an "out of town station".
> The WTHE operator thought I meant WKBW and of course I
> never DARED try to correct him, hi.    I did this maybe twice.
> 
> 1525 was in Russian with Chinese FS, ID was "govorit Pekin"
> by man, then woman, Internationale, strident dialogs,
> every time I heard them. Reception was with indoor loops
> and Hammarlund 129/150, whatever I had then.
> 
> As we head towards mid-winter, recall that for those of you near
> Washington State/Vancouver etc, a short path into Europe is
> possible at Vancouver SUNRISE, where it is mid-afternoon
> in Europe and the sun is already setting. I think NHP has had
> some success with this (1314) . This again is a very short
> window on the calendar.
> 
> Fascinating stuff for me.
> 
> - Bob                        1237 edt
> 
> 
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> 


Russ Edmunds
Blue Bell, PA  ( 360' ASL )
[15 mi NNW of Philadelphia]
40:08:45N; 75:16:04W, Grid FN20ID
<wb2bjh@xxxxxxxxx>
FM: Yamaha T-80 & APS9B @15'
AM: Hammarlund HQ-150 & 4' FET air core loop


		
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