Hi all
I am forwarding an interesting email from Murray ZL1BPU/ZL1EE he posted on
[email protected]
73 de la5vna
-----Original Message-----
From: Murray Greenman [mailto:[email protected]]
Sent: 15. januar 2012 23:38
To: Steinar Aanesland
Subject: Re: [Knightsqrss] QRP2000 / DG8SAQ Si570 USB synthesizer runs WSPR!
Steinar,
Yes, please do post it on the LF Group. I read the LF Group, but can't
currently post to it.
If anyone wants details of the simple modification to the DG8SAQ synthesizer
to add the LF range, send them my way. It takes just one chip (74HC4060),
and results in two ranges, 110kHz to 4MHz and 3.4MHz to 260MHz. The DG8SAQ
software is equipped to handle the divider and give direct reading and also
the correct frequency shifts.
I was operating this setup using WSPR on 600m the other night, and was
received in VK.
73,
Murray ZL1BPU
----- Original Message -----
From: "Steinar Aanesland" <[email protected]
To: "'Murray Greenman'" <[email protected]
Sent: Monday, January 16, 2012 10:04 AM
Subject: RE: [Knightsqrss] QRP2000 / DG8SAQ Si570 USB synthesizer runs WSPR!
Hi Murray,
This was very interesting. Is it OK for you that I repost this on
"[email protected]" ?
73 de LA5VNA Steinar
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Murray Greenman
Sent: 15. januar 2012 12:07
To: [email protected]
Subject: [Knightsqrss] QRP2000 / DG8SAQ Si570 USB synthesizer runs WSPR!
Hi,
I recently reported success with a simple method of making the
QRP2000/DG8SAQ Si570 USB synth operate the new OPERA mode. I'm not
convinced from recent tests that OPERA is an especially effective mode, so
I decided to see if I could operate the synthesizer with a much better mode
- MEPT_JT, commonly known as WSPR. And had instant success!
I ran Joe Taylor's WSPRcode.exe program to generate the code for my
special-purpose callsign, 'ZL1EE RF72 20'. I piped the result (from DOS) to
a text file, which I edited to remove all except the output code, which is
a series of numbers 0 - 3, representing the four tones of the WSPR mode. I
made sure all the numbers were in a single text line.
I wrote and ran a little BASIC program which stripped out the spaces, and
shifted up the numbers 0 - 3 to 7 - A, which represents the centre of the
MFSK range of the DG8SAQ pattern file (it accepts 0 - 9, A - F, with 8
being the nominal frequency). The program also adds an all-important 'Q' on
the end, which forces the MEPT mode of the DG8SAQ software to pause with
the TX off when it reaches the end of the file.
I made the necessary settings in the DG8SAQ software on the 'Special/MEPT
screen. I set the Time per Symbol to 0.6809206 (1/baud rate), the Frequency
Spacing to 1.4648Hz (spacing same as baud rate), set the Off Frequency to
10.13MHz and set the timer for 10 minutes. I watched the computer clock
(SNTP corrected) and at the exact round even minute, I checked the tick box
for Auto-transmit, and it then transmitted every 10 minutes, starting
exactly on the even minute. This timing is of course important for this
mode. On the main screen I set the transmit frequency to 10.14026MHz.
Using the DG8SAQ synthesizer connected to my 100mW transmitter (a 74HC240
chip, with PTT connected to the synthesizer), I connected up an antenna,
and waited for the start. The computer running the synthesizer control was
also running WSPR and receiving from the main shack rig on 30m, and was
receiving WSPR spots normally.
The first time it transmitted, I not only got a perfect decode from my own
WSPR program, but got two spots in the on-line WSPR database, both VK4s!
Despite known stability problems with the Si570, the received signal is
excellent - no drift, and dT (time offset) steady at -0.8s.
After less than an hour operating (transmitting every 10 minutes) I now
have
6 spots in the online WSPR database, none showing any drift. All reports
are from 2000km away! The signal reports are averaging -23dB SNR, and we
know WSPR is good for -33dB or so. Not bad for 100mW from a single CMOS
chip!
This is another example of the flexibility of this ingenious little
synthesizer, and also the flexibility and forethought that Tom has put into
the design of the software, allowing me to run these interesting modes so
easily.
73,
Murray ZL1BPU/ZL1EE
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