I have mentioned your method of using the 74HC84 chip with two xtals in an earlier Mail. I think I understand that way of generating the WSPR signal but the "magic" is in the PIC program. Have you ever considered offering programed PIC because I would like to try your method. I am guessing the PIC just carries your call, loc and power and is not alterable with out reprogramming the chip?
Have you written your rig up anywhere? I saw the 6m experiment article but as far as I could see it was a means of eliminating the PC and soundcard the output being a 1500c/s tone 4 FSK phase shited.
Anyway a very interesting practical solution.
73 es GL petefmt
--- On Wed, 7/4/10, g3zjo <[email protected]> wrote:
From: g3zjo <[email protected]>
Subject: RE: LF: WSPR without an SSB TRX ? FRM Joe Taylor NPwinner
To: [email protected]
Date: Wednesday, 7 April, 2010, 23:33
Just a bit more for you to mull over.
I don’t think anyone has mentioned the MP3 approach where a 2min WSPR data stream is recorded at audio and used to modulate the TX with suitable start stop timing.
Then there is my audio WSPR system which I call the XORgan, this generates WSPR at audio at a very stable base frequency derived from the difference between 2 identical xtals, one pulled 1,500Hz the other modulated, using an XOR chip.
Then there is Gene Marcus follow on of that idea with the tones generated directly by an audio oscillator, its frequency being varied by WSPR code.
Both of these methods need the WSPR to be coded in a PIC.
As I understand your application, with VCO facility there is no need for the audio mixing you mention, just use the PIC to modulate the VCO.
My WSPR on 503.810kHz uses this method, no GPS clocking just some accurate timing in the programming which has been running now for 2 years, recently I have had to attack the capacitance values due to Xtal ageing, it had gone outside the range of the trimmer. The timing thus needed correction within 24 hours, today, now I have done the mod, I did a reset after 4 days whether it needed it or not.
73
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Chris Osborn
Sent: 07 April 2010 22:41
To: [email protected]
Subject: Re: LF: WSPR without an SSB TRX ? FRM Joe Taylor NPwinner
Many thanks for all the contributions and suggestions.
I have been reading them and trying to understand but I am no 'boffin'.
Basically I have a 'decent' PC and appear to be receiving WSPR ok.
My rig is home built with a DC receiver and a simple CW type TX with VCO facility.
I am not at home with PIC's or programming and was hoping someone would come
up with an analogue solution.
I know I need to do more 'reading up' but was trying the lazy-man's approach.
My initial thoughts were that the PC is giving out a 1500 Hz tone + / - 5 Hz.
This is used to generate USB signals from an SSB TX (?)
I was hoping to mix these tones with a stable frequency of 1400 Hz (say) ending up
with 100 Hz + / - 5 Hz - thence to an F-V converter - gain / level adjusted and thence
to the TX VCO input.
Ready and
awaiting the brickbats.
73 Chris G3XIZ
I think we have been here before but this is my contribution:-
Do the whole thing with software WSPR - VAC - SDR software - Hardware Tayloe detector in reverse using a Multiplex chip.
This may not be the simplest technique taking the Applications involved i.e. writing the software. but it already exists so it is just a matter of integrating them to make a system. The Tayloe detector exists as a kit by Softrock. You do need however to amplify linearly from the detector output up to final o/p power level.
I use the reverse for WSPR RX on MF and LF. And have played with the TX side on 30m at about 1Watt O/P.
I can demonstrate this method if you are interested Chris, assuming watching paint drying (srri I mean WSPR) is the new attraction...hee.
From: M0FMT <[email protected]>
Subject: RE: LF: WSPR without an SSB TRX ? FRM Joe Taylor NPwinner
To: [email protected]
Date: Wednesday, 7 April, 2010, 20:55
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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