Is PSK31 still being used?

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Randy S.

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Apr 30, 2018, 1:46:40 AM4/30/18
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Hello,

I have been on a bit of a break from operating (since 2014) and I just recently set up a receiver. While poking around, I am not hearing PSK signals at all. What gives?

Thanks.

Patricia Wilson

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Apr 30, 2018, 2:59:23 AM4/30/18
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FT8 is the mode of choice for fast turnaround qsos. Check out the WSJT home page at 
But people who still want to converse are still using the psk modes. It is just that if all you are doing is chasing awards FT8 is it.

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Patricia Wilson
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RON DURAND

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Apr 30, 2018, 8:33:00 AM4/30/18
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I really preferred PSK31. It is unfortunate that it has been replaced in popularity by FT8, etc. I enjoyed being able to chat a bit. 

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Rick Donaldson - N0NJY

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Jul 15, 2018, 12:10:51 PM7/15/18
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I am still on psk31, usually on 20m.  I rarely do any other modes these days, and I'm running linux.  Have NOT figured out how to use FT8 anyway.  Seems a little weird to me. 

jimfraziernm

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Jul 15, 2018, 1:55:18 PM7/15/18
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If you want to learn FT8 I can send you a series of emails that helped 2 other hams get on the air with FT8.

I actually made a BPSK31 QSO last evening with VA3CTX on 20 meters. With the lack of sunspots resulting in poorer propagation conditions PSK31 QSOs have been a bit of a rarity, at least where I am located in New Mexico.

That is why FT8 has become a very popular mode. It is a weak signal digital HF communications mode that allows perfect message reception at a signal-to-noise ratio (SNR) down to -24dB (as measured over a 2500 Hz noise bandwidth). Whereas, my experience has been that PSK31 requires a SNR = -2 dB (again, as measured over a 2500 Hz noise bandwidth) to copy a perfect message. In short, FT8 has a perfect message reception threshold of -24dB and PSK31 has a perfect message reception threshold of -2dB.

What all this means is FT8 can achieve perfect message reception with a SNR 22 dB less than PSK31 [ -2 - (-24dB) ]. That means the FT8 SNR can be 158.5 times smaller than the PSK31 SNR and still get the same job done.

As a practical example, if you were able to work a FT8 QSO that resulted in a received SNR = -24 dB using a transmit power of 5 watts, it would require a PSK31  transmit power (5x 158.5) = 792.5 watts to attain the same performance.

73
KC5RUO





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Keith Freeouf

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Jul 15, 2018, 9:46:54 PM7/15/18
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Jim
I would be very grateful if you would be so kind as to forward me the email FT8 tutorials you referred to.
Thanks and 73
de Keith Freeouf, K9WAG


----- Original Message -----
From: jimfraziernm <jimfra...@comcast.net>
To: bps...@googlegroups.com
Sent: Sun, 15 Jul 2018 12:55:13 -0500 (CDT)
Subject: Re: [bpsk31] Re: Is PSK31 still being used?

If you want to learn FT8 I can send you a series of emails that helped 2 other hams get on the air with FT8.
I actually made a BPSK31 QSO last evening with VA3CTX on 20 meters. With the lack of sunspots resulting in poorer propagation conditions PSK31 QSOs have been a bit of a rarity, at least where I am located in New Mexico.
That is why FT8 has become a very popular mode. It is a weak signal digital HF communications mode that allows perfect message reception at a signal-to-noise ratio (SNR) down to -24dB (as measured over a 2500 Hz noise bandwidth). Whereas, my experience has been that PSK31 requires a SNR = -2 dB (again, as measured over a 2500 Hz noise bandwidth) to copy a perfect message. In short, FT8 has a perfect message reception threshold of -24dB and PSK31 has a perfect message reception threshold of -2dB.
What all this means is FT8 can achieve perfect message reception with a SNR 22 dB less than PSK31 [ -2 - (-24dB) ]. That means the FT8 SNR can be 158.5 times smaller than the PSK31 SNR and still get the same job done.
As a practical example, if you were able to work a FT8 QSO that resulted in a received SNR = -24 dB using a transmit power of 5 watts, it would require a PSK31  transmit power (5x 158.5) = 792.5 watts to attain the same performance.
73KC5RUO




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-------- Original message --------From: Rick Donaldson - N0NJY <rick....@gmail.com> Date: 7/15/18 10:10 (GMT-07:00) To: "bpsk31.com Discussion list" <bps...@googlegroups.com> Subject: [bpsk31] Re: Is PSK31 still being used?
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Amos

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Jul 15, 2018, 9:55:24 PM7/15/18
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Jim, I would appreciate any guidance, as I once used PSK31 quite a bit !  Thank you.  

Amos/KJ4PXJ

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jimfraziernm

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Jul 15, 2018, 10:15:15 PM7/15/18
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Sure, I'll get it out to you in a bit.

jimfraziernm

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Jul 15, 2018, 10:16:17 PM7/15/18
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Sure, I'll get it out to you in a bit.

73
KC5RUO



Jim Frazier

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Jul 16, 2018, 3:38:53 PM7/16/18
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FOR THE INTERESTED READER, ON THE SUBJECT OF PERFORMANCE DIFFERENCES OF FT8 vs BPSK31 IN WEAK SIGNAL CONDITIONS


Today I ran a laboratory test to determine the real BPSK31 perfect received message  threshold using my Rigol DSA815 spectrum analyzer. What I discovered was, that while the SNR message threshold difference between FT8 and BPSK31 is large, it is not as large as quoted below in yesterday's email.  The perfect message Signal to Noise Ratio threshold difference is a factor of 25 and not 158.5 as declared yesterday.  


Hence using yesterday's example, if you were able to work a FT8 QSO that resulted in a received SNR = -24 dB using a transmit power of 5 watts, it would require a PSK31  transmit power (5 watts  x 25) = 125 watts to attain the same performance. 


The perfect message reception SNR threshold for BPSK31 (measured over a receiver noise bandwidth of 2500 Hz) = -10 dB, not the -2 dB quoted yesterday.


The perfect message reception SNR threshold for FT8 is still -24 dB (measured over a receiver noise bandwidth of 2500 Hz).  Early literature, see ARRL QST magazine November 2017, Work the World with WSJT-X, Part 2: Codes, Modes, and Cooperative Software Development, Table 1, shows a S/N threshold of -20 dB. But, I think Franke and Taylor improved the processing algorithm such that one can receive a perfect message at -24 dB. Anyway, I had a FT8 QSO into Indonesia and that operator reported my SNR = -24 dB.  


So where does the factor of 25 come from?


FT8 SNR message threshold = -24 dB

BPSK31 SNR message threshold = -10 dB


SNR difference = -10dB - (-24 dB) = 14 dB


Convert the logarithmic value to a gain factor:  Gain factor = 10^(14/10) = 10^(1.4) = 25


FT8 uses a very sophisticated forward-error-correction coding scheme so this is sometimes referred to as the coding gain of one digital HF modulation scheme over the other.


FT8 has a coding gain of 14 dB over BPSK31. BPSK31 does not use any forward-error-correction.


73, and good DXing


KC5RUO

bort...@hotmail.com

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Oct 26, 2018, 11:22:38 AM10/26/18
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Hal Muir

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Oct 27, 2020, 5:09:39 PM10/27/20
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Mostly in the evening after 7pm mountain time will I send a burst of CQ'S for anybody that is interested.  I do bounce between 20 & 40 meters.
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