OT: WSPR SNR to CW real world conversion
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OT: WSPR SNR to CW real world conversion
 
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I have used WSPR through the past years and have always been amazed at how far one can go on so little power. I have always wondered how does it’s Signal to Noise Ratio figures I’m getting from the reporting stations mean in relation to being heard using CW. In other words, how close to a SNR of 0 do I have to be to say that if I were on CW they would hear me and not need a computer? I take it that anything on the + side of zero would make it, but when watching the waterfall and listening to my receive audio (KX3) I can hear stations that I am reporting a SNR of –10 for example. I’m running 500mw into a 40m EFHW inverted sloper and have received a few SNR 0 and +1. I have attempted to look up this information but got bogged down in the math and formulas, most of which I don’t understand.
So would a reported SNR of –10 represent a reasonable number at which the reporting station would hear me if I simply switched from WSPR to CW, all other things remain the same, or is 0 the break point? tnx de George WD0AKZ --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: OT: WSPR SNR to CW real world conversion
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I don't recall where this table of Relative Sensitivity of Communication
Modes came from but for what's it worth:: Mode Signal to Noise Ratio Threshold WSPR -27 dB JT65 -24 dB FT8 -20 dB Olivia -17 dB PSK31 -7 dB CW -1 dB RTTY +5 dB SSB +10 dB *Allan Zadiraka* *AB8OU* 4110 State Rd Akron, OH 44319 Work: 234-738-4578 Cell: 330.760.4569 Home: 330.644.1839 On Fri, Jul 20, 2018 at 1:03 PM George Pasek <[hidden email]> wrote: > I have used WSPR through the past years and have always been amazed at how > far one can go on so little power. I have always wondered how does it’s > Signal to Noise Ratio figures I’m getting from the reporting stations mean > in relation to being heard using CW. In other words, how close to a SNR of > 0 do I have to be to say that if I were on CW they would hear me and not > need a computer? I take it that anything on the + side of zero would make > it, but when watching the waterfall and listening to my receive audio (KX3) > I can hear stations that I am reporting a SNR of –10 for example. I’m > running 500mw into a 40m EFHW inverted sloper and have received a few SNR 0 > and +1. I have attempted to look up this information but got bogged down > in the math and formulas, most of which I don’t understand. > > So would a reported SNR of –10 represent a reasonable number at which the > reporting station would hear me if I simply switched from WSPR to CW, all > other things remain the same, or is 0 the break point? > > tnx > de George > WD0AKZ > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: OT: WSPR SNR to CW real world conversion
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On 7/20/2018 10:49 AM, Allan Zadiraka wrote:
> I don't recall where this table of Relative Sensitivity of Communication > Modes came from but for what's it worth:: I would estimate that FT8 is 6-10 dB better than CW with very good CW operators on both ends. Last I heard from K1JT, JT65 is a few dB better than FT8, and JT9 a few dB better than JT65. I can quote from this experience on 160M with JT65 and FT8. I'm near San Francisco. For most of the winter of 2016-17, in pursuit of the last three states I needed for QRP 160 WAS, I let JT65 run all night and kept a record of all the stations I decoded. I logged stations from all continents, including a dozen EU stations, and several times a week, VK6IR (about 8,000 miles). I also logged stations from every state except VT (one I needed) and most VE provinces. This past winter, there was virtually no JT65 activity, replaced by FT8. I heard a lot east coast stations working EU, but I didn't log a single EU station. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: OT: WSPR SNR to CW real world conversion
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In reply to this post by Allan Zadiraka
What is the referenced bandwidth for the noise? 3 KHz? And what if I
narrow the filter bandwith to just the occupied bandwidth of each signal? With fldigi when I have filter narrowed the measured snr goes to 30 dB. So the snr algorithm is very sensitive to filter width. Have not looked in the code to try to figure out if the snr measurements are comparing the signal to adjacent empty FFT buckets. 73, tom w7sua On 7/20/2018 10:49 AM, Allan Zadiraka wrote: > I don't recall where this table of Relative Sensitivity of Communication > Modes came from but for what's it worth:: > > Mode > > Signal to Noise Ratio Threshold > > WSPR > > -27 dB > > JT65 > > -24 dB > > FT8 > > -20 dB > > Olivia > > -17 dB > > PSK31 > > -7 dB > > CW > > -1 dB > > RTTY > > +5 dB > > SSB > > +10 dB > > > > *Allan Zadiraka* > *AB8OU* > 4110 State Rd Akron, OH 44319 Work: 234-738-4578 Cell: > 330.760.4569 Home: 330.644.1839 > > > > > On Fri, Jul 20, 2018 at 1:03 PM George Pasek <[hidden email]> wrote: > >> I have used WSPR through the past years and have always been amazed at how >> far one can go on so little power. I have always wondered how does it’s >> Signal to Noise Ratio figures I’m getting from the reporting stations mean >> in relation to being heard using CW. In other words, how close to a SNR of >> 0 do I have to be to say that if I were on CW they would hear me and not >> need a computer? I take it that anything on the + side of zero would make >> it, but when watching the waterfall and listening to my receive audio (KX3) >> I can hear stations that I am reporting a SNR of –10 for example. I’m >> running 500mw into a 40m EFHW inverted sloper and have received a few SNR 0 >> and +1. I have attempted to look up this information but got bogged down >> in the math and formulas, most of which I don’t understand. >> >> So would a reported SNR of –10 represent a reasonable number at which the >> reporting station would hear me if I simply switched from WSPR to CW, all >> other things remain the same, or is 0 the break point? >> >> tnx >> de George >> WD0AKZ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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