Re: LF: RE: 137 kHz SWL report from a tube Audion

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hello Mike, LF,

Nice to hear from you here, the first time for me i think.
Many thanks for the report, also to Terry/GW0EZY. Which receiver do you 
use and which CW filter did you choose? How long are you member of the 
reflector and what have you done on 137 so far, or what do you plan?
I'm also impressed by the signal here in 200km distance. I just took a 
walk in the forest and made a recording and took some captures. From 
this location you can see the Netbook, RX and ferrite antenna 
http://dl.dropbox.com/u/19882028/LF/FerriteantennaintheforestJO41.jpg
It's very comfortable to have a complete LF receive system in a bagpack, 
leight weight and sensitive. It does not need a ground and does not need 
to be highly lifted above he ground. Trees are no problem.
DCF39 is 90 dB S/N in 1 Hz NBW, 
http://dl.dropbox.com/u/19882028/LF/DCF39aus%20dem%20Sauerland.png (when 
the antenna points to DCF)
My own signal is strongest when the loop just cancels out DCF, it is 50 
dB S/N in 1 Hz then, 
http://dl.dropbox.com/u/19882028/LF/DK7FCaus%20dem%20Sauerland.png I'm 
however not sure if the signal peak level is correct due to the keyed 
signal...
Unfortunately there were no other LF amateur signals on the band...

73, Stefan/DK7FC




Am 30.04.2012 14:17, schrieb Mike:
> Hi Stefan
> You have provided me with my first amateur signal on 136 you
> are 559 now
> 1216utc IO90MS09 South Coast England. Perfect copy with a
> 10m vertical.
> 73 de Mike G3JVL
>
> -----Original Message-----
> From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of
> Stefan Schäfer
> Sent: 30 April 2012 11:29
> To: rsgb_lf_group@blacksheep.org
> Subject: LF: 137 kHz SWL report from a tube Audion
>
>
> Hello group,
>
> Since yesterday in the afternoon, i'm running a CW beacon
> again at 137.0
> kHz. Speed is about 25 BPM i guess.
> It was intended to generate a test signal for my antenna
> tests here in
> the holiday camp in JO41.
> After seeing two interesting spots in the DX cluster (
> http://www.dxsummit.fi/CustomFilter.aspx?customCount=50&cust
> omRange=137
> ) i decided to run it some days longer, knowing that many LF
> listeners
> can cross the way (=spectrum) and note that there is
> something going on
> in the LF amateur band.
>
> This time i got a mail from Horst/DL2SAV near Stuttgart
> (JN48 i think).
> He gave me a very interesting report. He is using no amateur
> radio to
> receive LF but an old tube radio from the 60's
> (Schaub-Lorenz) and a
> homemade tube Audion. He tells that DCF39 seems to work as
> the BFO, so
> he can hear me in normal AM mode, like a NDB. Today he sent
> me 3
> recordings which sound very fascinating for me. If you want
> to listen,
> here the link:
> http://dl.dropbox.com/u/19882028/LF/DK7FC_137kHz_30Apr12_amT
> ag_mit_Audion.mp3
> http://dl.dropbox.com/u/19882028/LF/Dk7FC_137kHz_30Apr_12_mi
> t_Radio_Schaub_Lorenz.mp3
> http://dl.dropbox.com/u/19882028/LF/DK7FC_137kHz_30_Apr_112_
> mit_Audiion.mp3
>
> What i don't understand: If DCF39 is the BFO and i am
> transmitting at
> 137.0, then the CW sidetone should be 1830 Hz (LSB,
> 138.83-137.0)? But
> the tone from the Audion sounds rather like 800 Hz for me.
> Maybe someone
> has an explanation.
>
> BTW the beacon is stilll on the air...
>
> 73, Stefan/DK7FC
>
>
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