Message-ID: <506EE6BA.90007@iup.uni-heidelberg.de>
Date: Fri, 05 Oct 2012 15:55:06 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: T/A and recent LF/MF changes at DK7FC and a more available
 MF Grabber
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Hello Jay, LF,

A late thank you for the report and capture.

Short report what is new and happend here:
We had a loss of our web- and mail-server here for more than 1 day, so i 
don't know if my previous answer to your email is lost or came through...

I also lost the contact to my old notebook which i exclusively use to 
generate tones for steering the PA. It is mounted in a fixed and closed 
position, so i can't see the screen, only by using a teamviever remote 
software access. But now i'm back and will put some more kWh of RF 
energy into the iono :-)

Ah BTW, i did some changes on my LF receive antenna. Beeing impressed by 
the excellent performance of the Twente WEB SDR and my need to have 
another fixed antenna installation for 472 kHz i decided to try a new 
active E field antenna circuit. The design is now a step closer to the 
PA0RDT design (now using a wideband input, a source follower in the 
first stage, i.e. no voltage gain).
But the main and very significant improvement was achieved by trying 
another location. This is only 2m higher from the top of the building, 
i.e. now in *37m AGL*. It is fixed on a pole of a WX station. I never 
expected such a difference. The complete building seems to be covered by 
a *QRM-cloud* which greatly decreases with the distance, even in that 
little height difference.

Now i can see the 630m band much more clear and several QRM lines 
disappeared. The same applies to LF! Also the LF/MF background noise is 
now not any more affected by the nearby resonant transmit antenna (not 
at all!). This is only due to the location (i made a test with the new 
antenna circuit on the old location). So now it is moch more easy to 
become QRV on MF, which was the goal.

Still not sure but maybe my LF reception is much better now. I will rise 
the antenna height by another 1...2m. Then i will give LF CW a new 
chance :-) However there is still a local drifting noise source which 
rises my LF noise floor...

Yesterday i worked DD7PC on 472.5 kHz who was a real 599 here, stronger 
than all NDBs.

I discovered the *world of receiving* instead of transmitting ;-) Due to 
the RX improvements i will receive in *OP32* and *WSPR* in the coming 
days, *transmissions apprechiated*!
My MF RX shall be running permanently, allowing to run a more permanent 
available MF grabber to coordinate activity and check the band as seen 
here. http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_MF_Grabber.html

I have to do some more tests and mods to the equipment but am optimistic 
to have a good progress.

73, Stefan/DK7FC






Am 03.10.2012 13:32, schrieb jrusgrove@comcast.net:
> Stefan & T/A enthusiasts
>
> Your signal popped out of the noise for just one sequence ... probably 
> a combination of 'constructive' propagation and a small improvement in 
> DST ... which I believe was ~ -25 to -30 nT at the time. Never say 
> never ...
>
> Jay W1VD  WD2XNS  WE2XGR/2 

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Hello Jay, LF,<br>
<br>
A late thank you for the report and capture.<br>
<br>
Short report what is new and happend here:<br>
We had a loss of our web- and mail-server here for more than 1 day, so
i don't know if my previous answer to your email is lost or came
through...<br>
<br>
I also lost the contact to my old notebook which i exclusively use to
generate tones for steering the PA. It is mounted in a fixed and closed
position, so i can't see the screen, only by using a teamviever remote
software access. But now i'm back and will put some more kWh of RF
energy into the iono :-)<br>
<br>
Ah BTW, i did some changes on my LF receive antenna. Beeing impressed
by the excellent performance of the Twente WEB SDR and my need to have
another fixed antenna installation for 472 kHz i decided to try a new
active E field antenna circuit. The design is now a step closer to the
PA0RDT design (now using a wideband input, a source follower in the
first stage, i.e. no voltage gain). <br>
But the main and very significant improvement was achieved by trying
another location. This is only 2m higher from the top of the building,
i.e. now in <b>37m AGL</b>. It is fixed on a pole of a WX station. I
never expected such a difference. The complete building seems to be
covered by a <b>QRM-cloud</b> which greatly decreases with the
distance, even in that little height difference.<br>
<br>
Now i can see the 630m band much more clear and several QRM lines
disappeared. The same applies to LF! Also the LF/MF background noise is
now not any more affected by the nearby resonant transmit antenna (not
at all!). This is only due to the location (i made a test with the new
antenna circuit on the old location). So now it is moch more easy to
become QRV on MF, which was the goal.<br>
<br>
Still not sure but maybe my LF reception is much better now. I will
rise the antenna height by another 1...2m. Then i will give LF CW a new
chance :-) However there is still a local drifting noise source which
rises my LF noise floor...<br>
<br>
Yesterday i worked DD7PC on 472.5 kHz who was a real 599 here, stronger
than all NDBs.<br>
<br>
I discovered the <b>world of receiving</b> instead of transmitting ;-)
Due to the RX improvements i will receive in <b>OP32</b> and <b>WSPR</b>
in the coming days, <b>transmissions apprechiated</b>!<br>
My MF RX shall be running permanently, allowing to run a more permanent
available MF grabber to coordinate activity and check the band as seen
here.
<a class="moz-txt-link-freetext" href="http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_MF_Grabber.html">http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_MF_Grabber.html</a> <br>
<br>
I have to do some more tests and mods to the equipment but am
optimistic to have a good progress.<br>
<br>
73, Stefan/DK7FC<br>
<br>
<br>
<br>
<br>
<br>
<br>
Am 03.10.2012 13:32, schrieb <a class="moz-txt-link-abbreviated" href="mailto:jrusgrove@comcast.net:">jrusgrove@comcast.net:</a>
<blockquote cite="mid:000801cda15a$d09f1eb0$6401a8c0@JAYDELL"
 type="cite">Stefan &amp; T/A enthusiasts
  <br>
  <br>
Your signal popped out of the noise for just one sequence ... probably
a combination of 'constructive' propagation and a small improvement in
DST ... which I believe was ~ -25 to -30 nT at the time. Never say
never ...
  <br>
  <br>
Jay W1VD&nbsp; WD2XNS&nbsp; WE2XGR/2 </blockquote>
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