Paul,
You recently mentioned that you built a LF down-converter. So i bet you
are skilled enough to build a LF up-converter too :-) Then you don't
need a transceiver any more.
For generating the input signal to the converter, use SpecLab.
For the LO, use a NEO-7M based signal generator. It just remember that
IW4DXW did that some time ago. Find his email in the attachment. This
also anwers your EbNaut issues i think.
I just ordered another module for playing with that time pulse :-)
73, Stefan
Am 10.12.2018 20:16, schrieb N1BUG:
Hi Stefan,
Well for QSOs if your receiver/transmitter allow you can set the VFO
higher, like 136.500 and then the 843 Hz puts you higher in the band.
But anyway, in the current version JT9-5 and JT9-10 are not working
at all so we have to wait. Rik has his hands full with other
important aspects of program development.
Maybe JT9-10 will not work for me because of frequency drift in my
transceiver. :-( We will see about that when JT9-10 is ready for
testing.
I *will* soon transmit WSPR-15. As you know I recently had problems
with both PAs. One failed *while* I was transmitting WSPR-15. Both
are now repaired but I wanted to put some time on them with lower
duty cycle before trying that mode again.
After a few nights of this JT9-1 / JT9-2 beacon test (or if no
interest, maybe just one night!) I will try WSPR-15. I am very
interested to get back to that.
73,
Paul
--- Begin Message ---
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To: |
LF Group <[email protected]> |
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Subject: |
LF: Simple coherent frequency generator |
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From: |
Riccardo Zoli <[email protected]> |
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Date: |
Fri, 7 Jul 2017 09:48:43 +0200 |
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Hi Markus, Domenico, Stefan, LF
many thanks for last EbNaut decodes, dr Markus. And thanks Domenico
for your outstanding EbNaut automatic decoder!
In these days we have got good results using stand-alone NEO-M8N (or
NEO-7M as well) modules like reference frequency generator: (no more
external TCXO, OCXO, PLL,
etc....hi); obviously, the module with his patch antenna should be
installed in a good position. The output signal isn't affected by a
significant jitter (up to 1 MHz) and remains very stable in phase.
-A VERY SIMPLE COHERENT FREQUENCY GENERATOR (SCH1.JPG)-
We need only a buffer on TP5 (pin3 of the U-blox hybrid, connected
normally to the status LED) to adapt levels and impedance toward
amplifier.
SCH1.JPG is a simple solution tested by Tony IK1HGI, with GPS and
buffer installed outside the house. The square wave signal is applied
to PA using about 10 meters of RG174.
The solution with RS-232(TTL 3.3V)->WiFi converter is a practical
option (it works fine in my shack): you could use a normal COM (TTL
3.3V) to USB adapter.
Use "U-center" (by U-blox -
https://www.u-blox.com/en/product/u-center-windows) to pre-configure
the module.
After connecting it, it's necessary to set the navigation mode and
minimum elevation of sats (thanks to Domenico for the advice).
Go to...
- Menu - View
- Configuration view
- Select item "NAV5 (Navigation 5)" (left side)
- Set Dynamic Model to "Stationary" (right side)
- Set Min SV Elevation to 10 degrees
- Press Send button
- Select item "TP5 (Timepulse 5)" (left side).
- Select Frequency and Duty Cycle mode (right side)
- Set Duty cycle values (50% normally)
- Set QRG values Frequency and Frequency Locked; normal or x2 with
G0MRF PA (http://www.g0mrf.com/630m.htm) or x4 with a generic SDR
quadrature generator like
74HC74 (normally used with H-mode mixers)
- Press Send button
...obviously we need GPS module status ALWAYS in locked mode to obtain
a valid coherent signal...
- Select item "CFG (Configuration)" (left side)
- Select "Save current configuration" (right side)
- Select all Devices (in particular I2C-EEPROM) by keeping pressing Shift key
- Press Send button
Now the module is programmed.
-BPSK MODULATOR (SCH2.JPG)-
Now we need a BPSK modulator to send EbNaut messages: the simplest
method uses XOR (or XNOR) logic ports.
This is a very cheap, but fine solution to be EbNaut QRV in TX.
In particular, this modulator can be used succesfully on G0MRF class D
PA (http://www.g0mrf.com/630m.htm) and tested by Tony IK1HGI, but also
in any other amplifier.
In this last case, it needs a proper signal buffer.
All the best
73 de Riccardo IW4DXW
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