Message-ID: <500DDCC7.9050705@iup.uni-heidelberg.de>
Date: Tue, 24 Jul 2012 01:22:47 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Chaff and LF
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Hi Laurence,

After reading your mail i took a look to VE7TIL's grabber. If there 
would really be an effect on LF propagation then maybe ther would be 
unexpected peaks on the DCF or DLF graph, but there are't.
You may ask JA7NI to generate a key down signal on LF and run the 
SpecLab plotter and search for peaks :-)
Probably the air force will not announce the next test. But maybe you 
have some good contacts, get the information and forward it to the 
group, discretely :-)

Hawaii. Are you often there? Place for a large directional LF antenna? :-)

73, Stefan/DK7FC


Am 23.07.2012 23:45, schrieb Laurence KL7UK:
>
> One of the most interesting weather reports this week was from Hawaii 
> - when a radar image showed a broad swarth of radar returns some 15 
> miles long and 1 mile wide gradually moving South with the prevailing 
> wind. I first thought it was a a weather gust front or rain squal but 
> the weather chappy says it was from the ongoing military exercises and 
> they had dropped a large amount of the chaff stuff (radar 
> sized/reflective) and it was causing the X band radar to show it in 
> detail.
>
> I was pondering - as I sat on the beach on Maui the next day whether 
> this form of chaff can actually produces anomolies below the frequency 
> engineered - as a lot of the new type of chaff has to cover a load of 
> GHz and MHz channelling - if the area is large enough, as this was, 
> and the drop density of reflective material is large enough whether it 
> would cause some effects as it appeared to be dropped from 30,000ft or 
> so...even down to LF...?
>
> Another anomoly was seen this morning when I was returning from 
> Honolulu back to Anchorage - I was approx 1200 miles South of 
> Anchorage and a Blue glow started to appear - firstly I thought it was 
> just a band of Green/Blue Auroral light we get fairly often but  as we 
> got closer it was the Notchtilucent clouds way way above us - banded, 
> stripes and globs of thin cloud being illuminated by the sun which was 
> way below our horizon and actually not even a pre glow. Now - this 
> isnt a normal radio thing either but on reading up on these clouds it 
> appears they too are radio reflective up to a point given the ions 
> that attach to the nulceous and given they appear to be sub-polar or 
> polar, and mostly a summer thing, when the temps are coldest at that 
> altitude Im wondering if some of the oddities we see on MF and HF are 
> caused by these clouds too...
>
>

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Hi Laurence, <br>
<br>
After reading your mail i took a look to VE7TIL's grabber. If there
would really be an effect on LF propagation then maybe ther would be
unexpected peaks on the DCF or DLF graph, but there are't.<br>
You may ask JA7NI to generate a key down signal on LF and run the
SpecLab plotter and search for peaks :-)<br>
Probably the air force will not announce the next test. But maybe you
have some good contacts, get the information and forward it to the
group, discretely :-)<br>
<br>
Hawaii. Are you often there? Place for a large directional LF antenna?
:-)<br>
<br>
73, Stefan/DK7FC<br>
<br>
<br>
Am 23.07.2012 23:45, schrieb Laurence KL7UK:
<blockquote cite="mid:BLU153-W7B8F81140FFCE4ED08C28CFDD0@phx.gbl"
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  <div dir="ltr">&nbsp;<br>
One of the most interesting weather reports this week was from Hawaii -
when a radar image showed a broad swarth of radar returns some 15 miles
long and 1 mile wide gradually moving South with the prevailing wind. I
first thought it was a a weather gust front or rain squal but the
weather chappy says it was from the ongoing military exercises and they
had dropped a large amount of the chaff&nbsp;stuff (radar sized/reflective)
and it was causing the X band radar to show it in detail. <br>
&nbsp;<br>
I was pondering - as I sat on the beach on Maui the next day whether
this form of chaff can actually produces anomolies below the frequency
engineered - as a lot of the new type of chaff has to cover a load of
GHz and MHz channelling - if the area is large enough, as this was, and
the drop density of reflective material is large enough whether it
would cause some effects as it appeared to be dropped from 30,000ft or
so...even down to LF...?<br>
&nbsp;<br>
Another anomoly was seen this morning when I was returning from
Honolulu back to Anchorage - I was approx 1200 miles South of Anchorage
and a Blue glow started to appear - firstly I thought it was just a
band of Green/Blue Auroral light we get fairly often but&nbsp; as we got
closer it was the Notchtilucent clouds way way above us - banded,
stripes and globs of thin cloud being illuminated by the sun which was
way below our horizon and actually not even a pre glow. Now - this isnt
a normal radio thing either but on reading up on these clouds it
appears they too are radio reflective up to a point given the ions that
attach to the nulceous and given they appear to be sub-polar or polar,
and mostly a summer thing, when the temps are coldest at that altitude
Im wondering if some of the oddities we see on MF and HF are caused by
these clouds too...<br>
&nbsp;<br>
&nbsp;<br>
  </div>
</blockquote>
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