From: DK7FC <73dk7fc@googlemail.com>
Message-ID: <551B07AA.5010900@gmail.com>
Date: Tue, 31 Mar 2015 22:46:34 +0200
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Subject: LF: WSPR at 4xf from a Raspberry Pi
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Hi MF,

Got no answer from PE1NNZ so i spent a bit more time and effort to 
'understand' the C-code, i.e. find the correct line where to put a '4*' 
to get what i want. I found it (it is: */double freq = 4*centerFreq + 
4*((double)(-511 + i))*symOffset/3.0;/* ).
I also compiled it successfully. Now i can externally set the same 
frequency (e.g. 475685) but the output and frequency shift is 4x higher. 
This can be passed through my /4 CD4013 stage, which is used to generate 
a perfect rectangular, opposite phase signal, after the input signal has 
been distorted a bit while passing an optocoupler (EMC stuff...).
I know several OMs are using such divide-by-4 stages, which, so far, 
didn't allow to transmit WSPR. Now, with the Raspy these days are gone, 
at least for me.
If some one is interested, i would of course share the code (you already 
see it and just need to find the line in your wspr.c file).
I'm now trying to run a bit more power as usual since the Raspi is 
directly connected to the (real) PA: 
https://dl.dropboxusercontent.com/u/19882028/MF/Raspi_to_QRO_link.jpg

73, Stefan

PS: Ooooh, of course it could be that someone did the same before me, 
maybe even better and so on...  so it is maybe not a 'first' whatever!!!!

Am 27.03.2015 14:27, schrieb DK7FC:
> [...]And i wrote an email to PE1NNZ and asked to a modification of the 
> C-program to generate a signal with 4x higher FSK shift. Then it it 
> would be possible to use that version for OMs having a divide-by-4 
> stage in their PA (to get a perfect 50% duty cycle and rectangular 
> shape (after passing optocouplers etc)).


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Hi MF, <br>
<br>
Got no answer from PE1NNZ so i spent a bit more time and effort to
'understand' the C-code, i.e. find the correct line where to put a '4*'
to get what i want. I found it (it is: <b><i>double freq =
4*centerFreq + 4*((double)(-511 + i))*symOffset/3.0;</i></b> ).<br>
I also compiled it successfully. Now i can externally set the same
frequency (e.g. 475685) but the output and frequency shift is 4x
higher. This can be passed through my /4 CD4013 stage, which is used to
generate a perfect rectangular, opposite phase signal, after the input
signal has been distorted a bit while passing an optocoupler (EMC
stuff...).<br>
I know several OMs are using such divide-by-4 stages, which, so far,
didn't allow to transmit WSPR. Now, with the Raspy these days are gone,
at least for me. <br>
If some one is interested, i would of course share the code (you
already see it and just need to find the line in your wspr.c file).<br>
I'm now trying to run a bit more power as usual since the Raspi is
directly connected to the (real) PA:
<a class="moz-txt-link-freetext" href="https://dl.dropboxusercontent.com/u/19882028/MF/Raspi_to_QRO_link.jpg">https://dl.dropboxusercontent.com/u/19882028/MF/Raspi_to_QRO_link.jpg</a><br>
<br>
73, Stefan<br>
<br>
PS: Ooooh, of course it could be that someone did the same before me,
maybe even better and so on...  so it is maybe not a 'first'
whatever!!!!<br>
<br>
Am 27.03.2015 14:27, schrieb DK7FC:
<blockquote cite="mid:55155AD6.1090102@gmail.com" type="cite">
  <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
[...]And i
wrote an email to PE1NNZ and asked to a modification of the C-program
to generate a signal with 4x higher FSK shift. Then it it would be
possible to use that version for OMs having a divide-by-4 stage in
their PA (to get a perfect 50% duty cycle and rectangular shape (after
passing optocouplers etc)). <br>
</blockquote>
<br>
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