Building a digital field strength meter for your PSK31 station NF6P – Dave Kalahar [email protected].
39
PERFECT PSK31 SIGNALS, AUTOMATICALLY. Building a digital field strength meter for your PSK31 station NF6P – Dave Kalahar [email protected]
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Transcript of Building a digital field strength meter for your PSK31 station NF6P – Dave Kalahar [email protected].
PERFECT PSK31 SIGNALS
AUTOMATICALLY
Building a digital field strength meter for your PSK31 station
NF6P ndash Dave Kalahardavenf6pcom
Author and Designer
George Rothbart KF6VSGOriginally Presented at the Pacificon 2003 Conference
Original PowerPoint at httpwwwssiservercominfopskmeter
OR wwwnf6pcom I promise to post by the end of the weekend
What we will cover this hourhellip 1048708 PSK31 signalling (how it works) 1048708 A PSK31 station and its components 1048708 Tuning up in PSK31 1048708 Over modulation the audio level problem 1048708 Building an RF monitor to solve the problem 1048708 Circuit diagram and hardware details 1048708 Firmware and Software routines 1048708 Performance 1048708 Where we go from here
Digital Modes (character- based data)
1048708CW 1048708RTTY 1048708Packet 1048708APRS 1048708SSTV 1048708PSK-31 (and now PSK-63 too)
Phase shift keyingmdashthe basicsZero bits are signaled by 180-degree phase reversals
To avoid harmonics the amplitude passes throughzero at the instant of the reversal of phase There is noneed to change the amplitude when we donrsquot changephase Thus we might see a signal amplitude like this
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
Author and Designer
George Rothbart KF6VSGOriginally Presented at the Pacificon 2003 Conference
Original PowerPoint at httpwwwssiservercominfopskmeter
OR wwwnf6pcom I promise to post by the end of the weekend
What we will cover this hourhellip 1048708 PSK31 signalling (how it works) 1048708 A PSK31 station and its components 1048708 Tuning up in PSK31 1048708 Over modulation the audio level problem 1048708 Building an RF monitor to solve the problem 1048708 Circuit diagram and hardware details 1048708 Firmware and Software routines 1048708 Performance 1048708 Where we go from here
Digital Modes (character- based data)
1048708CW 1048708RTTY 1048708Packet 1048708APRS 1048708SSTV 1048708PSK-31 (and now PSK-63 too)
Phase shift keyingmdashthe basicsZero bits are signaled by 180-degree phase reversals
To avoid harmonics the amplitude passes throughzero at the instant of the reversal of phase There is noneed to change the amplitude when we donrsquot changephase Thus we might see a signal amplitude like this
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
What we will cover this hourhellip 1048708 PSK31 signalling (how it works) 1048708 A PSK31 station and its components 1048708 Tuning up in PSK31 1048708 Over modulation the audio level problem 1048708 Building an RF monitor to solve the problem 1048708 Circuit diagram and hardware details 1048708 Firmware and Software routines 1048708 Performance 1048708 Where we go from here
Digital Modes (character- based data)
1048708CW 1048708RTTY 1048708Packet 1048708APRS 1048708SSTV 1048708PSK-31 (and now PSK-63 too)
Phase shift keyingmdashthe basicsZero bits are signaled by 180-degree phase reversals
To avoid harmonics the amplitude passes throughzero at the instant of the reversal of phase There is noneed to change the amplitude when we donrsquot changephase Thus we might see a signal amplitude like this
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
Digital Modes (character- based data)
1048708CW 1048708RTTY 1048708Packet 1048708APRS 1048708SSTV 1048708PSK-31 (and now PSK-63 too)
Phase shift keyingmdashthe basicsZero bits are signaled by 180-degree phase reversals
To avoid harmonics the amplitude passes throughzero at the instant of the reversal of phase There is noneed to change the amplitude when we donrsquot changephase Thus we might see a signal amplitude like this
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
Phase shift keyingmdashthe basicsZero bits are signaled by 180-degree phase reversals
To avoid harmonics the amplitude passes throughzero at the instant of the reversal of phase There is noneed to change the amplitude when we donrsquot changephase Thus we might see a signal amplitude like this
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
PSK31 signaling
These phase changes occur every 32 milliseconds (3125 Hz) Why this rate Because 1048708 It can be easily derived from the 8KHz signal generated by your sound card (8000 Hz divided by 256 = 3125 Hz) and 1048708 30 or so bits per second translates to about 50 wpm the fastest you can type A zero (space) is defined as a 180 degree phase reversal from the prior sample A one (mark) is defined as no phase change from the prior sample
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
PSK31 signaling
Notice that when we shift the signal one bit width (32msec) and compare the phase shift of 180 degrees is clear This also gives us a clue for how PSK-31 is detected and converted back to the digital world
Letrsquos look at PSK31 in the real world on an oscilloscope
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
The PSK-31 Station
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
bull A Bag of Parts that you can solder to a printed circuit board
bull Software ndash (Firmware) preinstalled
bull Software PC ndash Free and Easy to Use
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
YOU CAN BUILD THIS
Electronic Kitrsquos are Fun to Build We propose a club ldquobuild meetingrdquo Solder Stations Basic Tools Hands On
Help and Testing all in one 2 Hour night Walk away with a working usable shack
accessory Cost for Basic Kit is about $40
- Perfect PSK31 Signals Automatically
- Author and Designer
- Slide 3
- Slide 4
- Slide 5
- PSK31 signaling
- PSK31 signaling (2)
- Slide 8
- The PSK-31 Station
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
- Slide 21
- Slide 22
- Slide 23
- Slide 24
- Slide 25
- Slide 26
- Slide 27
- Slide 28
- Slide 29
- Slide 30
- Slide 31
- Slide 32
- Slide 33
- Slide 34
- Slide 35
- Slide 36
- Slide 37
- Slide 38
- YOU CAN BUILD THIS
-
