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Re: LF: Dual-speed WSPR

To: [email protected]
Subject: Re: LF: Dual-speed WSPR
From: IZ7SLZ <[email protected]>
Date: Mon, 01 Jun 2015 09:22:20 +0200
Cc: wolf_dl4yhf <[email protected]>
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Good day all,

i did a similar test on may 27  night by transmitting, in close time interval,  some WSPR-2  and WSPR-15 sequences. For Markus statistics, these are results:


Timestamp                    Call            MHz          SNR    Drift    Grid        Pwr    Reporter    RGrid        km        az
wspr-2 (5 spots)                                       
 2015-05-27 22:16      IZ7SLZ      0.475777      -16      0      JN80nu      100      IK1WVQ      JN44cb          813      299
 2015-05-27 22:16      IZ7SLZ      0.475778      -28      0      JN80nu      100      EA5DOM-1      IM98xn      1488      266
 2015-05-27 22:16      IZ7SLZ      0.475778      -27      0      JN80nu      100      DF2JP      JO31hh              1414      329
 2015-05-27 22:16      IZ7SLZ      0.475777      -25      1      JN80nu      100      PA3ABK/2      JO21it          1543      326
 2015-05-27 22:16      IZ7SLZ      0.475777      -24      0      JN80nu      100      F6GEX      IN97na              1591      302
wspr-15 (11 spots)                                       
 2015-05-27 22:00      IZ7SLZ      0.475763      -12      0      JN80nu      100      PA3ABK/15      JO21it      1543      326
 2015-05-27 22:00      IZ7SLZ      0.475821      -36      0      JN80nu      100      G3WCB      IO80di              1924      310
 2015-05-27 22:00      IZ7SLZ      0.475821      -27      0      JN80nu      100      DI2AX      JO44ad              1625      338
 2015-05-27 22:00      IZ7SLZ      0.475821      -27      0      JN80nu      100      DF2JP      JO31hh              1414      329
 2015-05-27 22:00      IZ7SLZ      0.475822      -19      0      JN80nu      100      DG3LV      JO53gv              1531      344
 2015-05-27 22:00      IZ7SLZ      0.475820      -36      0      JN80nu      100      SM2DJK      KP03au            2565      3
 2015-05-27 22:00      IZ7SLZ      0.475823      -20      0      JN80nu      100      DF8UO      JN48ex              1135      326
 2015-05-27 22:00      IZ7SLZ      0.475822      -26      0      JN80nu      100      EA5DOM-4      IM98xn         1488      266
 2015-05-27 22:00      IZ7SLZ      0.475821      -35      0      JN80nu      100      EA4NZ      IN80dm              1753      276
 2015-05-27 22:00      IZ7SLZ      0.475821      -27      0      JN80nu      100      DD7PC      JN49ax             1236      328
 2015-05-27 22:00      IZ7SLZ      0.475763      -15      0      JN80nu      100      IK1WVQ      JN44cb              813      299
wspr-2 (2 spots)                                       
 2015-05-27 21:56      IZ7SLZ      0.475778      -28      0      JN80nu      100      EA5DOM-1      IM98xn      1488      266
 2015-05-27 21:56      IZ7SLZ      0.475778      -24      0      JN80nu      100      DF2JP      JO31hh      1414      329
wspr-2 (5 spots)                                       
 2015-05-27 21:46      IZ7SLZ      0.475778      -24      0      JN80nu      100      F5WK      JN18hp      1432      312
 2015-05-27 21:46      IZ7SLZ      0.475778      -19      0      JN80nu      100      G6AVK      JO01ho      1736      319
 2015-05-27 21:46      IZ7SLZ      0.475778      -20      0      JN80nu      100      PA0A      JO33de      1595      333
 2015-05-27 21:46      IZ7SLZ      0.475777      -23      0      JN80nu      100      G8LCO      IO91vu      1799      319
 2015-05-27 21:46      IZ7SLZ      0.475778      -27      0      JN80nu      100      PI4THT      JO32kf      1485      332
wspr-15 (12 spots)                                       
 2015-05-27 21:30      IZ7SLZ      0.475821      -34      0      JN80nu      100      G3WCB      IO80di          1924      310
 2015-05-27 21:30      IZ7SLZ      0.475822      -26      0      JN80nu      100      DF2JP      JO31hh          1414      329
 2015-05-27 21:30      IZ7SLZ      0.475821      -34      0      JN80nu      100      DD7PC      JN49ax          1236      328
 2015-05-27 21:30      IZ7SLZ      0.475820      -36      0      JN80nu      100      SM2DJK      KP03au          2565      3
 2015-05-27 21:30      IZ7SLZ      0.475818      -38      0      JN80nu      100      DK7FC/P      JN49ik          1159      328
 2015-05-27 21:30      IZ7SLZ      0.475819      -37      0      JN80nu      100      2E0ILY      IO82                  1998      317
 2015-05-27 21:30      IZ7SLZ      0.475822      -18      0      JN80nu      100      DG3LV      JO53gv          1531      344
 2015-05-27 21:30      IZ7SLZ      0.475817      -25      1      JN80nu      100      G4JVF      IO93if              1949      321
 2015-05-27 21:30      IZ7SLZ      0.475821      -32      0      JN80nu      100      EA4NZ      IN80dm          1753      276
 2015-05-27 21:30      IZ7SLZ      0.475823      -27      0      JN80nu      100      DF8UO      JN48ex          1135      326
 2015-05-27 21:30      IZ7SLZ      0.475821      -34      0      JN80nu      100      DI2AX      JO44ad          1625      338
 2015-05-27 21:30      IZ7SLZ      0.475763      -16      0      JN80nu      100      PA3ABK/15      JO21it      1543      326
wspr-2 (6 spots)                                       
 2015-05-27 21:26      IZ7SLZ      0.475777      -28      0      JN80nu      100      SM2DJK      KP03au      2565      3
 2015-05-27 21:26      IZ7SLZ      0.475779      -19      0      JN80nu      100      PE1RKT      JO22fb      1575      327
 2015-05-27 21:26      IZ7SLZ      0.475777      -25      0      JN80nu      100      PA3ABK/2      JO21it      1543      326
 2015-05-27 21:26      IZ7SLZ      0.475777      -25      0      JN80nu      100      G8LCO      IO91vu      1799      319
 2015-05-27 21:26      IZ7SLZ      0.475778      -19      0      JN80nu      100      PA0RDT      JO11tm      1572      324
 2015-05-27 21:26      IZ7SLZ      0.475778      -25      0      JN80nu      100      EA5DOM-1      IM98xn      1488      266

These are very few data to perform a good statistic analisys for a SNR comparison.
BTW i can  observe a consistent increase of spots for WSPR-15, taking also in account that number of WSPR-2 receivers are, i guess, more than WSPR-15.

On 5/31/2015 9:10 AM, wolf_dl4yhf wrote:

Greetings all,

About the different SNR indications of WSPR-2 and -15 :
The question is how WSPR estimates the "noise" vale .. possibly using the 'lower quartile' method described by G4JNT once upon a time, i.e. sorting the FFT frequency bins from a certain frequency range (which.. ?) by amplitude and taking the <N/4-th> bin, corrected by something, as an estimate for the noise level ?
In that case, because I guess the frequency bins are only 1/8th as wide in WSPR-15 than in WSPR-2, the indicated noise level may depend a lot on the drift rate of all those 'nasty little QRM spikes' (in the spectrum), and this may be different for each and every receiver location.

Here are my decodes for DF6NM and G4JNT (maybe Markus wants to compare)..

WSPR-15:

2245 -2 -1.3 0.475824 0 DF6NM JN59 27

2315 -20 -0.6 0.475810 0 G4JNT IO90 33

2330 -8 -1.3 0.475824 0 DF6NM JN59 27

2345 -17 -0.6 0.475810 0 G4JNT IO90 33

0015 -15 -0.9 0.475810 -1 G4JNT IO90 33

0030 -2 -1.3 0.475824 0 DF6NM JN59 27

0100 -17 -0.6 0.475810 0 G4JNT IO90 33

0130 -11 -0.6 0.475810 0 G4JNT IO90 33

0130 -6 -1.3 0.475824 0 DF6NM JN59 27

0230 -5 -1.3 0.475824 0 DF6NM JN59 27

0245 -20 -0.6 0.475810 0 G4JNT IO90 33

0330 -7 -1.3 0.475824 0 DF6NM JN59 27

0345 -31 -0.9 0.475810 -1 G4JNT IO90 33


(btw interesting to see G4JNT dropping so low at 03:45, guess that one would possibly NOT have been decoded in WSPR-2)



DF6NM in WSPR-2:
2328 -11 -1.5 0.475791 0 DF6NM JN59 27
2346 -11 -1.7 0.475791 0 DF6NM JN59 27
0028 -7 -1.7 0.475791 0 DF6NM JN59 27
0046 0 -1.5 0.475791 0 DF6NM JN59 27

0128 1 -1.5 0.475791 0 DF6NM JN59 27

0228 -3 -1.5 0.475791 0 DF6NM JN59 27
0246 -2 -1.7 0.475791 0 DF6NM JN59 27


0328 -5 -1.4 0.475791 0 DF6NM JN59 27

0346 -12 -1.5 0.475792 0 DF6NM JN59 27


From the last transmission (03:30 to 03:45 in WSPR-15): -7 dB
Average between the adjacent WSPR-2 transmissions: -8.5 dB

(-> very similar results as from SM2DJK and DG3LV....  -15 shows 1.5 dB "better")


73,
  Wolf DL4YHF
   (receiver several hundred meters away from houses, but mains-fed -> QRM)







Am 31.05.2015 02:07, schrieb Markus Vester:
Yeah maybe. But at the moment I'd rather keep things as simple as possible, and I anyway wouldn't expect a sharp optimum regarding speed.
 
The idea is to compare the SNR of the slow sequence with the average of the two surrounding fast sequences, received by the same monitor. If the dB results were the same, we could probably exploit the full 9 dB advantage due to the lower threshold (-38 vs -29 dB), otherwise we'd have to subtract the dB difference.
 
Results from first round:
 
 2015-05-30 23:46   DF6NM   0.475791   -11   0   JN59nj   0.5   DL4YHF   JO42fd   359   330 
 2015-05-30 23:30   DF6NM   0.475824   -8   0   JN59nj   0.5   DL4YHF   JO42fd   359   330  
 2015-05-30 23:28   DF6NM   0.475791   -11   0   JN59nj   0.5   DL4YHF   JO42fd   359   330
=> WSPR-15 SNR happened to be 3 dB better!
 
 2015-05-30 23:46   DF6NM   0.475790   -15   0   JN59nj   0.5   SM2DJK   KP03au   1694   15
 2015-05-30 23:30   DF6NM   0.475823   -13   0   JN59nj   0.5   SM2DJK   KP03au   1694   15 
 2015-05-30 23:28   DF6NM   0.475790   -14   0   JN59nj   0.5   SM2DJK   KP03au   1694   15
=> WSPR-15 shows 1.5 dB better.
 
 2015-05-30 23:46   DF6NM   0.475792   +1   0   JN59nj   0.5   DG3LV   JO53gv   502   356 
 2015-05-30 23:30   DF6NM   0.475824   -2   0   JN59nj   0.5   DG3LV   JO53gv   502   356 
 2015-05-30 23:28   DF6NM   0.475792   -8   0   JN59nj   0.5   DG3LV   JO53gv   502   356
=> WSPR-15 shows 1.5 dB better.
 
This is an unexpected result, implying that the advantage of WSPR-15 would be more than 9 dB, instead of less. But on the other hand the dB values may not be telling the whole story, because the threshold for a fading signal might still be higher than -38 dB.
 
All the best,
Markus (DF6NM)

From: DK7FC
Sent: Sunday, May 31, 2015 1:33 AM
Subject: Re: LF: Dual-speed WSPR

Markus,

What about the old slow-WSPR by DF6NM? It could be useful to try WSPR-4 for experiments. There is not just 2 and 15. And WSPR-120 on VLF... No problem!

73, Stefan

Am 31.05.2015 01:28, schrieb Markus Vester:
To allow SNR comparisons at different speeds, I will transmit a mixed-mode beacon tonight. It will consist of two WSPR-2 sequences, before and after a WSPR-15 sequence on each odd half hour:
 
hh:28 - hh:30: WSPR-2 475.790 kHz
hh:30 - hh:45: WSPR-15 475.823 kHz
hh:46 - hh:48: WSPR-2 475.790 kHz
 
Transmitter power is currently 25 watts into an antenna with 2% efficiency. Am listening to both modes at all other times.
 
All the best,
Markus (DF6NM)


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