Hi Pete / group
I must have been scribing at the same time
as you J
I haven’t abandoned computers
completely for WSPR particularly when TX/RX is required. Where it becomes silly
is with a QRP TX when the computer uses far more power than the TX. My 500kHz
WSPR, PIC, TX and PA uses 76mA from a solar panel and that’s it.
73.
-----Original
Message-----
From: [email protected]
[mailto:[email protected]] On
Behalf Of M0FMT
Sent: 07 April 2010 23:00
To: [email protected]
Subject: Re: LF: WSPR without an
SSB TRX ? FRM Joe Taylor NPwinner
What I am saying is that simplicity in that it's all
done in the PC with software already written (no need to reinvent the wheel)
no need to program PICs etc. Unless of coarse you want it PCless then
there is point to it. The WSPR software exists the Virtual Audio
Cable (VAC) exists and a SDR TX software exists. Just down load and run. For
the end user, a no -brainer! The only hardware is the Multiplex chip
Quadrature detector 90degree phase shift Local oscillator to give a sideband
signal on the desired frequency to be amplified to final O/P. i.e.
Softrock TX RX. cheap kit!
That's what I am trying to suggest.
I note that G3ZJO has made a simple phase shift modulator driven with a PIC
for WSPR using a 74HC86 chip.see http://g3zjo-radio.blog.co.uk/2009/10/26/wspr-organ-computerless-wspr-tx-7249318/ That
may also be a good SSB rig less method for 500kc/s but not tried it
because the above method I have suggested does not rely on a PIC
programmer which I don't have and I have already built Softrock TXRX and
the rest is soldering iron less PC software exercise.
Joe Taylor said in his reply to me that what you
have suggested is being done.
If you write up a surefire design I for one would
like to build it .
In the mean time the only surefire method I have
made that does not require an SSB rig is the one I described above. i.e make
an SDR TXRX and use plug and play software. And its cheap as chips to put
together.
I grant you it is not PCless but it is SSB rigless,
one out of two...........
BTW I agree with your comment ..Why reject a PC
out of hand.
From: Andy Talbot <[email protected]>
Subject: Re: LF: WSPR without an SSB TRX ? FRM Joe Taylor NPwinner
To: [email protected]
Date: Wednesday, 7 April, 2010, 21:53
Not quite sure what you're trying to suggest...
There is no 'magic' to a phase continuous
oscillator. Any single oscillator whose frequency is controlled
by adjusting the frequency determining element will inherently have to
be phase continuous. Simple examples are a varicap tuned LC or crystal
source, or a DDS where changing the increment to the NCO is the tuning
element.
In the former you may have a problem getting
sufficiently close enough to a 1.46Hz shift (actually the value is 12000/8192
= 1.46484375Hz). But for a DDS no problem, even with many stages
of frequency multiplication. I have only ever used the DDS
implementation, but there are many people out there who have built highly
sucessful low power WSPR beacons - many based around varicap controlled
crystal oscillators controlled from a microcontroller.
As mentioned before, JT4 is much the same as
WSPR, and I've tested many successful beacon sources for that, - in fact
the 10GHz beacon GB3SCX transmits JT4G using a DDS in a PLL, and controlled
to set one of four frequencies from another PIC generating the JT4G
symbols. http://www.scrbg.org/JT4_GB3SCX.pdf
The only really critical thing about the mode is
gettign the symbol timing right. Be just a fraction of a
percent out and after the 110 second transmission period, if you have drifted
by more than about 20% of the 680ms long symbol period, decoding will
suffer. Actual start time of the transmission can vary by a
few seconds either way, but symbol timing MUST be better than
0.1%. No big deal for a crystal oscillator, but the PIC code must
gets its counters and division ratios right! (Certain cheap sound
cards cannot manage it though)
But, while on the same subject. Why reject a
PC out of hand. They are now so ubiquitous, that old laptops
appear at rallies/boot sales/junk fairs and cost next to nothing.
Almost anything running Win 98 or later will do for WSPR and WSJT - although
you may have to use an external USB headphone dongle if the internal soundcard
is too ancient. (a couple of quid from Ebay)
At the recent Bournemouth Sale, I saw Toshiba
laptops (135MHz clock running Win 98) identical to the one I use
currently 24/7 for the 5MHz beacon monitoring project, being sold by a
trader for a mere £15 each. You could probably find a
suitable one on a rubbish tip even, fully working. I also picked
up a very nice Toshiba lightweight notebook (700 MHz clock) Win XP for
£40 a couple of years ago, and have to stop buying old laptops as they're
just too plentiful now.
On 7 April 2010 20:55, M0FMT <[email protected]>
wrote:
Please see below reply from Joe Taylor on this
very subject September last year, This is the guy who actually wrote this
application (you might say from the Horse Mouth) and he said :-
Hi Peter,
> Does your Software have a data output that gives a hi lo i.e 0,1 on
the serial port other than the PTT Hi Lo?
No.
> If the software doesn't have this facility why not?
Because there is no standard, nor even anything remotely approaching one,
that would permit hard-keying an oscillator to produce continuous-phase
4-FSK with offset 1.465 Hz between tones.
The WSPR program, as distributed, is essentially a sound card mode.
With that said, it should be noted that a number of people have built
special-purpose WSPR transmitters that implement the necessary 4-tone FSK
capability in hardware. Their keying is typically controlled from
a microprocessor, with the encoded message (sequence of tones) stored
in ROM.
-- 73, Joe, K1JT
From: Rik Strobbe <[email protected]>
Subject: RE: LF: WSPR without an SSB TRX ?
To: "[email protected]"
<[email protected]>
Date: Wednesday, 7 April, 2010, 14:23
hello Chris, Jim, group,
an alternative to a transverted would be a divider, let's say from 5MHz (from
a HF tranceiver) to 500kHz.
That would limit the hardware to some resistors an a single CMOS or TTL IC.
I have written a small apllication that generates the appropriate WSPR
audio signal based on the input frequency, output frequency and divider
ratio.
It worked fine for some local tests, but due to lack of I did no real
"DX tests" so.
But if anyone wants to try this route I will be happy to send the software.
73, Rik ON7YD - OR7T
________________________________________
Van: [email protected] [[email protected]] namens
James Moritz [[email protected]]
Verzonden: woensdag 7 april 2010 15:09
Aan: [email protected]
Onderwerp: Re: LF: WSPR without an SSB TRX ?
Dear Chris, Andy, LF Group,
What Andy suggests is fine for generating a WSPR signal, but receiving WSPR
via the PIC might be a bit more difficult...
But also at http://www.g4jnt.com/LFUpconv.pdf is Andy's simple phasing
up-converter, which could be used to convert a PC audio output to 500kHz
and
be used in place of the VCO in your TX.
Trawling through the Forum topics on the WSPRnet.org website (you might
have
to sign up to see all the material) will reveal many designs for homebrew
HF
WSPR beacons that could mostly be adapted to 500k.
Cheers, Jim Moritz
73 de M0BMU
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