Talk:PSK31

Bandwidth

The image doesn't show PSK31 bandwidth. LeighKlotz

Sound Sample

There is no sound sample. LeighKlotz

AM Modulation

PSK is not produced by modulating the RF carrier directly; that would produce AM. LeighKlotz

I believe PSK is usually FM modulated, although I think it can be AM modulated. This is true for most data radio modulation modes, even standard TV signals. Esentially, the data is modulated to an audio frequency signal, which is in turn modulated, usually with AM or FM. --ssd 15:40, 24 December 2005 (UTC)

PSK31 uses Single sideband modulation - while one could use FM or AM to send the audio generated by a PSK program, the resulting signal would NOT be a PSK31 waveform, and would NOT have the narrow bandwidth of PSK31. In effect, the computer + the SSB transmitter form a Software defined radio with the first local oscillator being the numerically-controlled oscillator in the PSK software and the first intermediate frequency being the audio signal out of the soundcard. N0YKG 19:54, 10 April 2006 (UTC)

CB

Somebody wrote: "A serious user of the Citizen's Band is an oxymoron". Well, first thanks for your comment, which really added much value to the page. I can't speak for the USA, but here in Europe we have some CBers who take their art seriously. Some who I have spoken with could probably just walk into the Advanced exam and pass it with flying colours. They just don't want to, as they prefer the friendly, inclusive atmosphere of CB to the self-righteous, cliquish, 'anal' image of ham radio that such comments project. Chris G4PDJ 08:08, 8 February 2007 (UTC)

Emission Code

Not wishing to open a can of worms, but what is the correct emission code for PSK31?. I make it 'J1B' (i.e. 'J' = SSB with suppressed - or nowadays - 'no' carrier; '1' = One channel containing digital information, and 'B' = Automatic telegraphy for machines to read). To be honest, I just write 'PSK', ' Ritty', 'CW' or 'SSB' in my log, but just wondering :-) 86.170.182.192 (talk) 01:00, 29 September 2010 (UTC)

• It would be G1B G for phase modulation. Graeme Bartlett (talk) 12:10, 29 September 2010 (UTC)
  • Hmmm...That was my first thought too, but you are not phasing the carrier, you are phasing the sideband. I'll just write 'PSK', and if the man from the RA doesn't know what that means, He's in the wrong job :-)86.170.182.192 (talk) 12:54, 30 September 2010 (UTC)
  • Second thoughts. I've read through Peter M's article three times now. There is one confusing reference in there about the phase shifts being like swapping the wires of a twin feeder over 31 times a second. That would be phase-shift keying, but Peter is then talking about somebody else's earlier idea, which gave him the 'genesis' of varicode. PSK31 is (as Peter says) just like high-speed morse. It is purely a transmitted 'sound'. You can cross-connect two computers' sound cards and send PSK31 back-and-to between them without any carrier (or for that matter even a radio) being involved. In fact, if my laptop's microphone 'overhears' my rig, it can even read the code through air!. The PSK 'idle' signal (i.e constant 10101010 reversals) is identical to a stream of high-speed morse 'dits' (albeit 'smoothed' with a longer rise and fall time); and 'no reversal' is a 'dah', but only twice as long and not three times longer like morse. To read PSK, the software looks at the demodulated audio level and compares it to how it was 32 milliseconds ago. If the voltages are the same then that is one state, and if they are different that is the other state. Really really clever, simple and elegant. Therefore I would say that the emission code is the same as for very high speed machine-readable morse, not 'on-off keyed', but sent as audio 'beeps' through the microphone. So it's 'J1B' for an SSB transmitter; 'F1B' for an FM one, etc. etc. 86.170.182.192 (talk) 18:21, 30 September 2010 (UTC)

Oh dear, I've done it now. Several people have twigged that I am G4PDJ, and my mailbox groaneth. Yes, Peter G3PLX is a very very clever man, and I even used to work him on 'Subspace' (joke). But on the basis that it takes an idiot to write an idiot's guide...here's mine.

1. It is not my place to tell anybody else what to do. Call PSK31 what YOU want to in YOUR log, and I will call it J1B in mine !!!

2. The beauty of PSK31 is that it is so easy to get on the air in a few minutes, without ever really needing to know how it actually works in detail. Only people who really should get out more (like me) need to delve deeper :-)

The real genius lies in Peter M's varicode alphabet. Varicode is like a soldier marching to the sound of a metronome. For as long as he marches 'left-right-left-right', then that's the 'idle' tone, but if he pauses on one foot and then carries on marching, he will be out-of-step with the other soldiers until he does it again and comes back into step. When he pauses on one foot, that means 'no shift this time'; and when he takes a step that's a shift. The PSK 'warble' that we all know and love - if you slow it down - is a rapid stream of smooth 'beeps' of varying lengths (the soldier's footsteps), and the 'beeps' go in and out of time against a 31 Hz clock, which is the metronome. When sending each letter, our soldier actually spends more time pausing than marching, because if he takes two steps, that ends one letter and starts the next.

People just picked up on the word 'phase' in isolation. In fact the only place where 'phase' happens is when keying the soundcard's modulator. It's important to stress that we are talking about the soundcard's audio frequency modulator here – not the other one in the radio (in fact just forget about the radio altogether for now). Instead of being keyed between zero-and-positive like morse, the soundcard is keyed by reversing polarity between positive and negative. This is why the resulting envelope looks like two interlaced sine waves crossing over each other at 'zero', instead of two sine waves in mirror-image above and below the 'zero' line as in normal AM.

This is where the confusion arises. Whatever radio you use, it only transmits whatever noise comes in through the microphone socket. The PSK 'whistle' sound is transmitted a few kilohertz away from the carrier frequency (according to where you click your mouse on the waterfall). The rig's RF carrier stays in the same phase throughout, and is irrelevant anyway as (on SSB at least) it is not even transmitted in the first place.

Looking back, perhaps it would have been better if Peter, as inventor, had stuck to his guns and made us call his new mode 'varicode' ritty (as opposed to AFSK/ASCII ritty). I know this sounds a bit like me telling God that he could maybe have called The Bible something else, but I hope you will forgive my sheer cheek just this once :-). 86.170.182.192 (talk) 23:04, 4 October 2010 (UTC) p.s. I've put a version of this on my qrz.com page. That one is public domain, so feel free to do what u want with it (G4PDJ).