[Moon-net] [Magic Band EME] scattering of eme signals by MS ?
Lance Collister
w7gj at accessoutwest.com
Wed Nov 21 09:05:56 CST 2007
Dennis, you have me thinking more about this....maybe it was basically a
"multipath" type of interference. That is, the meteors alone certainly
cannot provide the propagation halfway around the world, but perhaps
they could provide reflections/scatterring of incoming signals that are
in the vicinity of the receiver. If these signals are doppler shifted I
would think they could seriously disrupt JT65 decodes. I would have
thought that the direct EME signals would be weak enough to receive on
their own, but as long as the meteors are passing near the main lobe of
the antenna, they may provide enough reflected signal to the receiver to
register as interference. Given the increased meteor scatter on 6m as
compared to the higher EME frequencies, perhaps it is not surprising
that it has not previously been reported as a problem outside of 6m
EME.... ???? 73, Lance
K7bv at aol.com wrote:
> Ian,
>
> I had the same experience while trying an EME contact with an EA. The
> meteor scatter sounding pings were very disruptive during the
> attempt. My occurrence was during summer Es season so I wrote it off
> to an Es path that was one hop short of complete between us - the
> position of the moon had the two of us pointed nearly down the correct
> bearing for a direct path.
>
> 73,
> Dennis K7BV
>
> M0bcg at aol.com wrote:
> > hi all ;
> >
> > i was monitoring lance and mick w1jj over the weekend and have been
> > seeing for what i can best describe as meteor scatter pings on
> the EME
> > signals .
> >
> > initially id been having a few problems when running ZAP and not
> being
> > able to decode lance or mick when they were very strong signals,
> but
> > soon found that because of the strength of signals that ZAP was
> treating
> > them as "birdies" , as soon as i stopped using ZAP then i was
> getting
> > decodes without problem .
> >
> > on saturday i heard mick w1jj calling CQ and alongside his
> spectran
> > traces i saw the same effect that i see from european stations
> when they
> > are running eme and i get pings from them , i didnt take a lot
> of notice
> > of this until tonight though because it happened again when he was
> > calling UN8GC and i had quite a few pronounced audible and
> trace marked
> > pings which showed short bursts on spectran with a little shift
> in freq
> > to the eme signal .
> >
> > the same things happened whilst i was listening to lance on
> sunday ,
> > quite loud pings at intervals on his transmit periods .
> >
> > now i know i am unlikely to see meteor scatter signals from
> lance over
> > that distance and also the path between here and mick is 5235km
> which
> > will discount that too .
> >
> > has anyone else been seeing meteor scatter pings from 6m eme
> signals
> > coming into the atmosphere at all ? , as opposed to pings from
> "local"
> > stations within 2000km or so that will occur anyway .
> >
> > i know its the leonids meteor shower right now , although the
> peak is
> > forecast not to be good, all the same though it is the peak of the
> > shower almost .
> >
> > i only see the pings on the strong EME signals of say -23db or
> better
> > and where i am seeing very big traces on spectran .
> >
> > mostly over the weekend lance and mick have both been sub -19db
> and as
> > low as -16db here .
> >
> > i am unsure if this is actually MS pings occuring or another
> form of
> > scattering of signals produced in conjunction with the meteors but
> > would be interested to know .
> >
> > all of this occured whilst my array was elevated up around
> 35degs and
> > looking south or south west .
> >
> > 73 ian G5WQ io91do
> >
> >
> >
> ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Magic mailing list
> > Magic at 6meme.com
> > http://6meme.com/mailman/listinfo/magic_6meme.com
> Hi Ian,
>
> Here is another possibility to think about... There are a TON of
> satellites
> spinning around up there, and as their solar panels line up
> properly, you can get
> VERY strong reflections from them. I wonder if maybe that could
> account for some
> of the signals you saw - even perhaps in combination with random
> meteors.
>
> I know I have purposely bounced 6m signals off satellites before,
> and the
> geosynchronous satellites are high enough to cover quite a broad
> area. The lower
> ones, such as the ISS only cover about 3000 miles as they quickly
> go by. But it
> was the ISS that provided my only link into the TEP zone on 6m
> during the last
> cycle...Boy it was really amazing to hear all the QRM on
> 50.110!!! Well, for
> about 5 seconds, anyway, and then the satellite link was gone ;)
>
> Anyway, you raise some very interesting observations, and my point
> is this: They
> call it "The Magic Band" but there basically is just a TON of ways
> that signals
> can be propagated and as we continually add more and more junk up
> into space, 6m
> is undoubtedly going to become more and more "magic" ;-)
>
> GL and VY 73, Lance
>
> GL and VY 73, Lance
>
> --
> Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A,
> ZF2OC/ZF8)
> P.O. Box 73
> Frenchtown, MT 59834 USA
> QTH: DN27UB
> TEL: (406) 626-5728 URL: http://www.bigskyspaces.com/w7gj
> 2m DXCC #11, 6m DXCC #815
>
>
> _______________________________________________
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> Magic at 6meme.com
> http://6meme.com/mailman/listinfo/magic_6meme.com
>
>
>
>
>
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--
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8)
P.O. Box 73
Frenchtown, MT 59834 USA
QTH: DN27UB
TEL: (406) 626-5728
URL: http://www.bigskyspaces.com/w7gj
2m DXCC #11/6m DXCC #815
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