Dear all,
a real audion receiver usually contains an adjustable rf feedback so
that the rx can oscillate. Therefore a pitch of 800 Hz should be
obtainable without the reception of any other transmitter close to the
wanted signal.
73 Ha-Jo, DJ1ZB
"Stefan Schäfer" <[email protected]> schrieb:
> 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&customRange=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_amTag_mit_Audion.mp3
> http://dl.dropbox.com/u/19882028/LF/Dk7FC_137kHz_30Apr_12_mit_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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