Re: LF: Anti Social ssb

[Andy Talbot <andy.g4jnt@googlemail.com>]

For the narrow range of frequencies needed for WSPR, a 90 degree phase shift network at audio need consist of no more than a pair of CR's; although a pair of op-amp allpass networks does a better job.

 

Direct conversion from baseband to 137 or 500kHz by phase shifting teh audio, then followed by a Soft-rock style QSD in reverse.  http://www.g4jnt.com/LFUpconv.pdf

It would be simpler still if Joe could be persuaded to provide I/Q outputs from the soundcard.

 

May be slightly more complicated than a mixer from RF, but does mean you don't need to tie up the SSB rig transmitting all that HF output, only to lose it all again in an attenuator (assuming no low level output, of course)

Andy

2010/1/3 M0FMT <m0fmt@yahoo.co.uk>

OK Rik

 

May be your way is simpler. I was thinking along the lines of an existing SSB rig in most but not all shacks existing free software - 3 x 2n2222 devices a mixer chip an xtal and may be a fet pa like what G3XBM has proposed.

 

Phase shifting a carrier which in the software is done at audio in old Joe whats his names software can be done at RF cariier frequency granted .... but is it over all simpler than a transverter method described above?

 

Having built your 500kc/s transverter all other free to down load diggi modes are then possible (Goord 'elp us) even dare I say CW ........ oh thats not PC on this reflector forgot.....  slapped wrists.

 

73 HNY petefmt

From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>

Subject: Re: LF: Anti Social ssb

To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Sunday, 3 January, 2010, 17:16

Pete,

There is no need for linear amplification with WSPR, so things can be kept simple.
Another way to get a 500kHz WSPR signal is to generate WSPR with the tones 14.6Hz separated at 5MHz and then divide by 10.
As Andy states the WSPR protocol is public (and pretty straightforward), so writing the appropriate software shouldn'd be to hard.

73, Rik  ON7YD - OR7T

Quoting M0FMT <m0fmt@yahoo.co.uk>:

> Probably simpler to to make up a transverter - mixer with a xtal  controlled oscillator and a few stages of linear amplification  driving the mixer with an SSB rig. The whole thing about WSPR is the  Low power aspect so no QRO linears required if you play the game.  Then use the readily available Software that can be down loaded for  free.... no brain surgery required.
>
> 73 es GL petefmt
>
> --- On Sun, 3/1/10, Andy Talbot <andy.g4jnt@googlemail.com> wrote:
>
> From: Andy Talbot <andy.g4jnt@googlemail.com>
> Subject: Re: LF: Anti Social ssb
> To: rsgb_lf_group@blacksheep.org
> Date: Sunday, 3 January, 2010, 15:59
>
> There is a way...
>
> If you can arrange an oscillator so that it can be pulled onto the
> four WSPR tone frequencies (separated by 1.46Hz ) by two logic lines.
> This could be as simple as two resistors, one twice the value of the
> other, giving a 2-bit D/A converter, controlling a varicap on the
> oscillator.
>
> Then a PIC keyer can generate the logic level drive.
> See    www.g4jnt.com/WSPRBCNS.ZIP   for details of generating teh WSPR
> message and the PIC code
>
> The design in there uses a GPS receiver to get accurate timing, but
> with some trivial PIC code changes it could be made to work in a
> standalone manually trigerred mode.
>
> Perhaps there's a demand here...
>
> WSPR encoding on the fly is easy enough in a PC
> http://www.g4jnt.com/wspr_coding_process.pdf
> A prog could be written to output the two-bit data via a USB/Serial
> port and PIC based dongle...
>
> Andy
> www.g4jnt.com
>
>
>
> Andy
> www.g4jnt.com
>
> This email has been scanned for damaging side-effects by the health
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> health, but may contribute to dissolving the nether and polar regions
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>
>
> 2010/1/3 Graham  <g8fzk@g8fzk.fsnet.co.uk<http://uk.mc281.mail.yahoo.com/mc/compose?to=g8fzk@g8fzk.fsnet.co.uk>>:
>> Roger
>>
>> '''  More people should use WSPR - '''
>>
>> That's not as  easy as  it  sounds , wspr  needs  a  liner audio to  rf
>> carrier frequency  conversion,  ...fine  if you have a  conventional
>> transverter , mf exciter or ham set that works down to  500/137 ...No good
>> if you  have dividing logic in the amplifier  drive train , vfo  controlled
>> or PIC based without the  'ability'  to  run a wspr  generating  code set ..
>> Its a  good  point worth making though ...
>>
>> G..
>> From: Roger Lapthorn
>> Sent: Saturday, January 02, 2010 10:20 PM
>> To:  rsgb_lf_group@blacksheep.org<http://uk.mc281.mail.yahoo.com/mc/compose?to=rsgb_lf_group@blacksheep.org>
>> Subject: Re: LF: Anti Social ssb
>> Mal,
>>
>> Some suggestions:
>>
>> More people should use WSPR - lots of stations (more than 100 at a time
>> based on 10MHz usage) are able to operate together within just a 200Hz slice
>> of the band allowing very useful data on propagation and station
>> performance/changes to be determined.  This would leave plenty of room
>> elsewhere in the band for CW and other narrowband conversational modes.
>> Occasional testing with SSB, for those allowed to use it (not UK), is of
>> interest to me as a listener, but I agree that it's not a good idea to use
>> this mode when the band is open for really long-distance DX if interference
>> to weak signals is likely.
>> You should try a New Year resolution: "I will be more tolerant and moan
>> less".
>>
>> 73s and a happy New Year to all on this reflector
>>
>> Roger G3XBM
>>
>>
>>
>>
>> 2010/1/2 mal hamilton  <g3kevmal@talktalk.net<http://uk.mc281.mail.yahoo.com/mc/compose?to=g3kevmal@talktalk.net>>
>>>
>>> I am afraid we have a SSB beacon on 508 kcs spreading over 3 kcs wide and
>>> S9 plus with me. Beacon SM6BHZ is causing QRM to those of us trying to
>>> listen and work the East Coast USA stations. I cannot understand why a
>>> station is licensed to work SSB in such a narrow band allocation.
>>> The 500 kcs band is a Shambles swamped by beacons.
>>> Does anyone else have an opinion?
>>> G3KEV
>>>
>>
>>
>> --
>> -------------------------------------------------------------
>> http://g3xbm-qrp.blogspot.com/
>> http://www.g3xbm.co.uk<http://www.g3xbm.co.uk/>
>> G3XBM    GQRP 1678      ISWL G11088
>>
>>
>>
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