RBN Analytics

Skimmer frequency accuracy

To be a good RBN citizen a skimmer should have a frequency accuracy of 2ppm or better.

To use the data below to improve the accuracy of your skimmer, multiply the current value of FreqCalibration in your skimmer software’s settings file with the suggested adjustment factor listed below.

The location of the settings files are:
CW Skimmer Server: %appdata%\Afreet\Products\SkimSrv\SkimSrv.ini
CW Skimmer: %appdata%\Afreet\Products\CwSkimmer\CwSkimmer.ini

The data listed below is based on yesterday’s RBN data, 00:00 to 23:59 UTC. This means that when making adjustments, changes in calibration will typically not have full impact on the listed data until the second day after the change.

The deviation estimates are based on spots on all active bands (40m and higher) from the respective skimmer. If different hardware is used for different bands, the deviation number may thus not represent the actual deviation for a particular band.

A link to the software used to produce the tables can be found at the bottom of this page. It runs as a cron job in an Ubuntu container on my Synology server and uploads to this WordPress website shortly after midnight UTC daily.

The deviation estimation is done in two steps. The first step uses a small number of highly accurate skimmers (called “anchors” in the code, typically GPSDO-controlled skimmers) as reference. The whole estimation process is then repeated one more time but using both the anchors as well as all skimmers determined to be the “good” as reference. The “good” skimmers are those with less than 0.15ppm average deviation from the anchors, producing more than 100 qualifying spots (the qualification criterion of spots are outlined below.)

Repeating the analysis with this this extended set of skimmers as frequency references drastically increases the geographical coverage of the analysis thereby increasing the number of qualifying spots which means a much more reliable deviation estimates for all skimmers. The skimmers used as reference skimmers in the second stage (i.e. both anchors and “good”) are marked with an asterisk in the table below.

When looking at the numbers, keep in mind that the deviations estimated by the algorithm are 100 to 1000 times smaller than the 100Hz resolution of RBN frequency data. The input data is thus extremely “noisy” which inevitably leads to statistical variations. This is also the reason for not including spots under a certain frequency. Doing so would skew the statistics and cause underestimation of the frequency error.

Due to propagation characteristics, operator behavior (e.g. small QSY), and just statistical variations due to the 100Hz rounding, some skimmers selected as reference skimmers in the first stage may have more than 0.2ppm deviation in the second stage. This is not an error.

If you do not see your skimmer in the list below in spite of it successfully feeding spots to RBN the most likely reason is that it is off in frequency. The analytics discards all spots from skimmers having more than 0.5kHz frequency error.

974158 RBN spots between 2023-12-10 00:00 and 23:59 UTC.
283567 spots (29.1%) were from reference skimmers (*).
Average spot flow was 677 per minute from 199 active CW skimmers.

396526 spots from 198 skimmers qualified for analysis by meeting
the following criteria:
 * Mode of spot is CW.
 * Also spotted by a reference skimmer within 1000 spots.
 * Also spotted by a reference skimmer within 10s. 
 * SNR is 3dB or higher. 
 * Frequency is 7000kHz or higher. 
 * Frequency deviation from reference skimmer is 0.5kHz or less.
 * At least 5 spots from same skimmer in data set.

  Skimmer    [ppm]  Spots    Adjustment 
  -------------------------------------
  2E0EBM      +0.2     60   1.000000238
  3B8CW*      +0.1   1691   1.000000143
  3D2AG       -0.3    844   0.999999750
  5W1SA       +2.1     95   1.000002064
  7Q6M        -3.3    204   0.999996746
  9M2CNC      +0.0     14   1.000000000
  AA4VV       -0.1    145   0.999999921
  AC0C-1      +0.1   3255   1.000000121
  BA6KC       -0.1    211   0.999999915
  BD7JNA      -0.4      8   0.999999554
  BG4GOV      +0.0     55   1.000000000
  BH4RRG      +0.2    132   1.000000189
  BH4RRG0     +0.3    175   1.000000306
  BH4RRG00    +0.4    166   1.000000389
  BH4RXP      +0.1    492   1.000000126
  BH4XDZ      -0.0    160   1.000000000
  CT1EYQ*     +0.2    800   1.000000169
  DC8YZ*      +0.1   5260   1.000000080
  DD5XX       -1.3   3544   0.999998666
  DE0QPG      -1.3   1436   0.999998730
  DE1LON      +0.4   5847   1.000000369
  DF2CK       +1.0   7268   1.000001040
  DF7GB*      -0.0   3468   0.999999995
  DJ1RK       -2.5   3157   0.999997505
  DJ2BC       -0.3   3713   0.999999698
  DJ9IE*      +0.1    290   1.000000059
  DK0TE       -2.2   4615   0.999997756
  DK3UA       -1.0    455   0.999998979
  DK9IP*      -0.1   3034   0.999999905
  DK9IP-1*    +0.0   4180   1.000000001
  DL0LA       +0.2   3036   1.000000242
  DL0PF       -1.6   4320   0.999998434
  DL1HWS*     +0.0   4132   1.000000025
  DL8LAS      +0.9   4218   1.000000879
  DL8TG*      -0.1   4371   0.999999909
  DL9GTB*     -0.1   2608   0.999999939
  DM5GG*      +0.1   4052   1.000000059
  DM6EE       +0.0    161   1.000000044
  DM7EE*      +0.0   2455   1.000000048
  DR4W        -2.4   3600   0.999997630
  E28AC       +3.8    336   1.000003826
  E77DX       +2.4    750   1.000002436
  EA1RX       -2.2    157   0.999997773
  EA1URA      -0.5   1943   0.999999525
  EA2CW       -0.5    684   0.999999499
  EA2RCF-4    -0.4   1444   0.999999600
  ES2RR*      +0.0   2327   1.000000007
  EY8ZE       -0.3    420   0.999999677
  F1TRE       -1.8     31   0.999998159
  F4EGZ       +0.7   2378   1.000000691
  F4VVG       -0.1   2056   0.999999856
  F6IIT       -0.5    312   0.999999494
  F6KGL       +0.2    952   1.000000206
  G0KTN       +0.3   3576   1.000000273
  G3YPP*      +0.1    427   1.000000067
  G4IRN       -0.2    741   0.999999756
  G4ZFE*      +0.1   4094   1.000000102
  GI4DOH      +0.2    911   1.000000151
  HA1VHF      -1.9   4025   0.999998114
  HA8TKS      +0.2   2854   1.000000208
  HB9BXE*     -0.0   2968   0.999999988
  HB9DCO      -0.4   2256   0.999999609
  HG0Y        +4.9     33   1.000004897
  HG8A        -1.7   4287   0.999998257
  IK3STG      +2.1   3325   1.000002083
  IK4VET*     +0.2   5279   1.000000173
  IU0MVD      +0.5     48   1.000000520
  JH4UTP      +0.5    369   1.000000470
  JH7CSU1     +4.4    308   1.000004406
  JI1HFJ      +0.2    210   1.000000235
  JJ2VLY      -0.9     25   0.999999114
  JN1ILK      -1.4    731   0.999998567
  K1RA        -0.3   4898   0.999999696
  K2PO/7      +0.6   2656   1.000000552
  K3LR        +0.0    888   1.000000019
  K3PA-1*     +0.4   3455   1.000000352
  K4PP*       -0.1   1947   0.999999898
  K5EM*       -0.1   1896   0.999999885
  K5TR        +0.6   1805   1.000000647
  K6FOD*      +0.0   2606   1.000000022
  K7EK*       +0.1    921   1.000000077
  K7MJG       +0.1    123   1.000000116
  K9IMM*      -0.1   2712   0.999999851
  K9LC*       -0.1    844   0.999999932
  KA7OEI      +0.1    160   1.000000109
  KC4YVA      +6.1   1427   1.000006054
  KD2OGR*     +0.2    616   1.000000169
  KH6LC       -0.2   1267   0.999999772
  KL7RA       -2.1   1622   0.999997922
  KM3T*       -0.0   4008   0.999999968
  KM3T-2      -0.4   4794   0.999999599
  KM3T-3      +0.4   4481   1.000000377
  KO7SS       -1.1   3112   0.999998862
  KP3CW       +0.5   4923   1.000000524
  KV4TT       +0.2    623   1.000000177
  LA6TPA      -3.5   1123   0.999996494
  LZ3CB*      -0.0   1822   0.999999999
  LZ4AE       +2.5   2320   1.000002537
  LZ4UX*      -0.1   1539   0.999999931
  LZ5DI       +0.2   1017   1.000000245
  LZ7AA       +0.6   1610   1.000000624
  MM0ZBH      -1.4   6100   0.999998638
  MM3NDH*     +0.0   4150   1.000000033
  MW0MUT*     -0.1   3759   0.999999895
  N2QT        -0.5    568   0.999999461
  N4ZR        +0.4   3236   1.000000442
  N6TV        +0.2    209   1.000000153
  N7TUG      +12.8   1270   1.000012812
  N8DXE       +0.5   1128   1.000000517
  N9CO*       -0.2   3481   0.999999784
  N9MKC       +0.2   1257   1.000000175
  ND7K        -2.7   3641   0.999997270
  NG7M        -0.8   1841   0.999999231
  NH6HI       +4.7      6   1.000004738
  NJ4P        +2.4   1875   1.000002368
  NN3RP*      +0.0    880   1.000000049
  NU6XB       +0.2    359   1.000000198
  OE6TZE*     +0.0   4080   1.000000023
  OE9GHV*     -0.0   4846   0.999999995
  OG66X       -0.9    231   0.999999135
  OG73X       -1.1    105   0.999998915
  OH0K/6      -1.7   3312   0.999998281
  OH2J        -1.9   3313   0.999998118
  OH4KA       -1.8    603   0.999998153
  OH6BG       +4.0   2278   1.000004033
  OK1FCJ*     -0.0   4855   0.999999955
  OK1HRA      -3.0   3659   0.999996976
  OK4QRO      +1.5   3043   1.000001453
  ON4EM       +0.0      8   1.000000000
  ON6ZQ       -0.4   3257   0.999999620
  OZ1AAB*     +0.1    839   1.000000096
  OZ1BZS*     -0.0    519   0.999999960
  OZ1HDF      +0.2    152   1.000000164
  OZ4ADX*     +0.1   1870   1.000000076
  P40L*       -0.1   2486   0.999999923
  PA0MBO*     +0.1   1108   1.000000108
  PA5KT       -1.9   1274   0.999998090
  PA8MM       -1.2    106   0.999998754
  PE5TT       -0.7   3423   0.999999287
  PJ2A        +0.3   1921   1.000000299
  R6YY        +0.1    523   1.000000072
  R9IR        -0.1    715   0.999999898
  RN4WA       +0.5   1873   1.000000477
  RU9CZD      -2.0   1970   0.999997999
  RW9AV       -0.3     37   0.999999658
  S50U        +1.4   1749   1.000001414
  S53A        -0.2   5895   0.999999848
  SE5E        -0.5   3618   0.999999530
  SM0TCZ      -1.5    502   0.999998500
  SM7IUN*     -0.1   3919   0.999999920
  SQ5J        +1.2   3007   1.000001243
  SV1CDN      -1.0     51   0.999998975
  SZ1A        +0.0    216   1.000000000
  TF3Y        +1.9   2718   1.000001872
  TF4M        -0.9   2165   0.999999083
  TI7W        -0.2   5819   0.999999832
  UA0S        -3.1    700   0.999996923
  UY2RA       +0.8   2631   1.000000789
  V51YJ       +2.1   1098   1.000002104
  VE6AO       -2.0   2559   0.999997961
  VE6JY       +0.8    954   1.000000840
  VE6WZ       +2.7   3541   1.000002655
  VE7CC       +0.6   2420   1.000000555
  VK2RH       -0.3     28   0.999999745
  VK3RASA     +1.1    133   1.000001127
  VK6ANC      -1.1   1182   0.999998870
  VR2FUN-77   -1.0   1098   0.999999048
  VY0ERC      +0.9     30   1.000000949
  W1NT-2      +0.5   4584   1.000000486
  W1NT-6      +0.3   6899   1.000000279
  W2AXR       +2.9    195   1.000002862
  W2LB        +0.0     20   1.000000000
  W2MV        +0.3    510   1.000000279
  W2NAF       +1.8   4376   1.000001779
  W3DAN       +0.5   1072   1.000000464
  W3LPL       -2.5   2114   0.999997509
  W3OA*       -0.1   4108   0.999999912
  W3RGA       +0.1   2796   1.000000132
  W3UA*       -0.0   6564   0.999999968
  W4AX        +3.3    625   1.000003280
  W4KAZ       -1.4    621   0.999998604
  W6BB        +0.3    550   1.000000274
  W6YX*       -0.0   2203   0.999999972
  W8WTS       -1.6   1627   0.999998408
  W8WWV       -2.1   3451   0.999997917
  WA7AI      +15.5   1871   1.000015477
  WA7LNW      -2.0   3391   0.999997992
  WB6BEE*     +0.0   2935   1.000000009
  WC2L        +0.5   2062   1.000000510
  WE9V        +2.4   2801   1.000002359
  WF7U        -0.4   1541   0.999999561
  WS3W        +0.2    361   1.000000190
  WZ7I*       -0.0   5772   0.999999967
  XV9Q        -0.1     64   0.999999944
  YO4RDW      +0.5    479   1.000000521
  ZF9CW*      +0.2    842   1.000000155
  ZL2KS       -1.8    154   0.999998227
  ZL3X        -2.6    539   0.999997433

Last updated 2023-12-11 00:16:23 UTC

Historical skimmer frequency accuracy

Below you will find historical accuracy data for the past ten days. Do not be concerned over minor daily variations. Since RBN spots only have 100Hz frequency accuracy, the input data is very noisy. Even for a perfectly accurate skimmer, the typical RMS rounding error across all shortwave bands is around 3ppm. This means that for a skimmer with 1000 spots per day the statistical variation is up to 0.2ppm. For skimmers with less than 100 spots per day the statistical variation can be above 2ppm. The content of the table below is based on the historical content of the above table.

Skimmer    1210  1209  1208  1207  1206  1205  1204  1203  1202  1201
---------------------------------------------------------------------
2E0EBM     +0.2  +0.3  +0.2  +0.2  +0.2  +0.1  +0.5       -20.8      
3B8CW      +0.1  +0.2  +0.1  -0.0  -0.4  -0.0  -0.2  -0.0  -0.5  -0.2
3D2AG      -0.3  -0.0  -0.0  +0.0  +0.6  +0.0  +0.3  -0.1  +0.0  -0.2
3V8SS                                                      -1.9  -1.7
4X6FB                                                      +0.5  +0.0
5W1SA      +2.1  +1.9        +3.6  +0.0              +1.5  +1.4      
7N4XCV                             +0.5  +0.0  -0.2  +0.5  +0.3  +0.0
7Q6M       -3.3  -3.1  -2.4                                          
9M2CNC     +0.0  +0.0  +0.0  +0.3  +0.6  +0.5  +0.0  +0.3  +0.2  -0.3
AA4VV      -0.1  -0.0  +0.0        +0.0  -0.0  -0.0  -0.1  -0.0  +0.1
AC0C-1     +0.1  +0.2  +0.1  +0.0  +0.2  +0.2  +0.2  +0.2  +0.2  +0.1
BA6KC      -0.1  -0.0  -0.2  +0.0  -0.4  +0.0  +0.0  -0.3  -0.2  +0.0
BD7JNA     -0.4                                      -0.4  -2.7      
BD8CS                                                +0.0  -0.1  +0.1
BG2TFW          +10.7  +7.1        +1.8  +6.1        +3.2  +6.4      
BG2UKX0          +6.4                                                
BG2UKX           +5.7                                                
BG4GOV     +0.0  +0.0  +0.0  +0.2                                    
BH4RRG00   +0.4  +0.4  +0.0  +0.9  +0.1  +0.0  +0.0  -0.2  +2.0      
BH4RRG0    +0.3  +0.2  +0.0  +0.0  +0.0        +0.0  +0.0  +0.1  +0.2
BH4RRG     +0.2  -0.0  +0.0  +0.0  +0.1  +0.0  +0.5  +0.0  +0.2  +0.1
BH4RXP     +0.1  +0.1  -0.1  -0.2  -0.0  -0.2  -0.5  -0.7  -0.6  -0.5
BH4XDZ     -0.0  +0.1  -1.1  -0.1  +0.0  +0.0  +0.0  -0.1  -0.2  +0.0
BI4RFP                                   +0.0  +0.0  +1.3  +0.0      
CT1EYQ     +0.2  +0.0  +0.1  -0.1  +0.0  +0.2  +0.1  +0.1  +0.2  +0.1
CT7ANO                                                           -2.9
CX6VM            +1.3  -3.7  -3.5  -3.8  -3.7  -3.8  -3.4  -2.9  -0.7
DC8YZ      +0.1  +0.2  +0.2  +0.2  +0.1  +0.2  +0.1  +0.3            
DD5XX      -1.3  -1.8  -1.7  -1.6  -1.9  -1.6  -2.8  -2.5  -2.6  -1.8
DE0QPG     -1.3  -1.6  -1.4  -1.3                                    
DE1LON     +0.4  -0.6  -0.2  -0.4  -0.4  +0.3  -0.2  -0.3  -0.3  +0.0
DF2CK      +1.0  +1.2  +0.8  +0.8  +0.6  +0.7  +0.3  +0.3  +0.4  +0.5
DF2CK-1          +0.4  +0.1  +0.0                                    
DF7GB      -0.0  +0.1  -0.0  +0.0  +0.0  -0.0  +0.0  -0.1  +0.1  -0.0
DJ1RK      -2.5  -3.0  -3.3  -3.4  -2.8  -3.0  -3.3  -4.0  -4.1  -3.6
DJ2BC      -0.3  -1.2  -0.4                    -0.6  -0.8  -0.6  -0.4
DJ9IE      +0.1                                                      
DK0TE      -2.2  -2.2  -1.8  -2.0  -2.4  -2.3  -2.7  -2.9  -2.9  -2.4
DK3UA      -1.0                                      -3.1  -3.1  -5.3
DK8NE                                                            -1.0
DK9IP      -0.1  -0.1  -0.1  -0.2  -0.0  -0.1  -0.1  -0.1  -0.2  -0.1
DK9IP-1    +0.0  +0.0  +0.1  +0.1  +0.1  -0.1  +0.1  +0.0  +0.1  +0.1
DL0LA      +0.2  +0.3  +0.1  +0.1  +0.1  +0.3  +0.2  +0.3  +0.4  +0.2
DL0PF      -1.6  -1.9  -1.9  -2.0  -2.1  -2.1  -1.9  -2.0  -1.7  -1.5
DL1HWS     +0.0  +0.1  +0.0  -0.1  +0.0  +0.2  +0.1  +0.2  +0.3  +0.0
DL8LAS     +0.9  +1.2  +0.7  +1.0  +1.0  +1.0  +0.9  +1.1  +1.1  +0.8
DL8TG      -0.1  -0.0  -0.1  +0.1  -0.0  -0.1  -0.2  -0.1  -0.0  +0.0
DL9GTB     -0.1  -0.0  -0.3  +0.2  +0.1  -0.5  -0.7  -0.6  +0.0  -0.3
DM5GG      +0.1  +0.0  +0.0  -0.0  +0.1  -0.0  +0.0  +0.0  +0.0  -0.1
DM6EE      +0.0  +0.1  +0.1  +0.1  -0.1  +0.2  +0.1  +0.1  +0.1  +0.1
DM7EE      +0.0  +0.3  +0.0  +0.1  +0.2  +0.2  +0.1  +0.1  +0.1  +0.1
DR4W       -2.4  -3.0  -3.9  -2.9  -3.6  -2.5  -3.8  -4.5  -4.5  -4.0
DV3A             +1.9              -8.0  -6.0 -10.4  -6.6  -6.6  -6.1
E28AC      +3.8  +4.0  +3.7  +2.4  +3.6  +4.4        +3.9  +4.7  +4.6
E77DX      +2.4                                                      
EA1RX      -2.2  -1.8  -6.7  -6.6  -2.5  -3.8  -6.1  -2.3  -3.8  -2.8
EA1URA     -0.5  -0.2  +0.1  +0.5  +0.8  +0.9  +0.5  +0.7  +0.6  +0.3
EA2CW      -0.5  +0.4  -0.4  -0.5  -0.4  -0.4  -0.4  -0.7  -0.5      
EA2RCF-4   -0.4  -0.3  -0.4  -0.5  -0.4  -0.5  -0.3  -0.4  -0.3  -0.2
EA5WU                                                            -0.4
ES2RR      +0.0  +0.0        +0.1  -0.1  +0.0  -0.1  -0.0  -0.0  -0.0
ET3AA            -0.3  -0.5  -1.0  -1.2  -1.3                        
EU1ST                              +5.7                              
EY8ZE      -0.3  -0.1  -0.2  -0.2  -0.4  -0.0  -0.2  -0.2  -0.1  -0.1
F1TRE      -1.8  -2.7                                                
F4EGZ      +0.7  +0.9  +0.6  +0.7  +0.9  +0.9  +0.7  +0.7  +0.9  +0.9
F4VVG      -0.1  -0.2  -0.2  -0.2  -0.1  +0.0  -0.0  -0.2  -0.0  -0.3
F6IIT      -0.5  -1.4  -1.0  -2.3  -1.2  -1.4  -0.7  -1.5  -1.4  -1.1
F6KGL      +0.2  -6.2  -8.6  -3.9  +0.0  +0.5              -0.0  +0.3
F8DGY            +0.0  -0.1  -0.2  -0.3  -3.7  -2.0  -0.4  -1.2  -5.6
G0KTN      +0.3  +0.5  +0.3  +0.4  +0.4  +0.4  +0.3  +0.4  +0.5  +0.4
G3XBI                                                +0.3  +0.3  +0.4
G3YPP      +0.1  +0.0  -0.2  +0.0  -0.3  -0.6  -0.1  +0.0  +0.0  +0.0
G4AON                  +0.6  +0.9  +0.9  +1.0  +0.8              +1.0
G4HSO                                                            +9.0
G4IRN      -0.2  -0.3  -0.2  -0.4  -0.6  -0.4  -0.6  -1.0  -1.1  -0.9
G4ZFE      +0.1  +0.2  +0.0  -0.2  -0.0  -0.0  +0.0  +0.0  +0.2  +0.2
GI4DOH     +0.2  +0.3  +0.2  +0.1  +0.1  +0.2  +0.4  +0.3  +0.3  +0.3
HA1VHF     -1.9  -2.2  -1.8  -1.7  -1.8  -1.8  -1.7  -1.9  -1.7  -1.3
HA5PP                                                      +1.4      
HA8TKS     +0.2  +0.3  +0.2  +0.3  +0.0  +0.5  +0.0  +0.3  +0.2  +0.2
HB9BXE     -0.0  +0.1  +0.0  +0.0  +0.2  +0.2  +0.1  +0.1  +0.2  +0.1
HB9DCO     -0.4  -0.3  -0.5  -0.5  -0.3  -0.4  -0.4  -0.4  -0.3  -0.4
HG0Y       +4.9  +5.7        +6.4  +6.2  +5.6  +6.2                  
HG5FMV                                   -0.1  +0.0  +0.2  +0.3      
HG8A       -1.7  -2.0  -1.2  -1.2  -0.8  -0.9  -0.8  -2.2  -2.0  -0.7
IK3STG     +2.1  +2.5  +1.9  +1.8  +1.9  +1.8  +1.6  +1.9  +1.8  +1.6
IK4VET     +0.2  +0.0  -0.0  +0.1  +0.0  -0.2  -0.0  +0.5  +0.8      
IU0MVD     +0.5                                                      
JH4UTP     +0.5  +0.6  -0.1  -0.8  +0.0                              
JH7CSU1    +4.4  +5.1  +3.4  +3.7  +3.9  +3.0  +4.3  +3.9  +4.3  +3.3
JI1HFJ     +0.2  +0.4  -1.0  -1.7  -1.5  -3.2  -3.3  +1.7  -7.0  -2.5
JJ2VLY     -0.9  -1.7  -0.4  -0.7  -4.2  -2.9  -2.6  -0.8  -0.1  +0.6
JN1ILK     -1.4  -1.7  -1.5  -1.2  +0.6  -1.6  -2.1  -3.6  -4.2  -3.8
K1RA       -0.3  -0.3  -0.3  -0.6  -0.4  -0.2  +0.1  +0.2  -0.3  -0.3
K2PO/7     +0.6  +0.6  +0.3  +0.4  +0.5  +0.4  +0.7  +0.2  +0.6  +0.3
K3LR       +0.0  +0.4  +0.4  -0.1  -0.2  -0.1  -0.1  +0.5  +0.2  -0.2
K3PA                               +0.0                              
K3PA-1     +0.4  -0.0  -0.0  +0.0  +0.0  +0.8  +0.5  +1.0  +1.0  +0.5
K4PP       -0.1  +0.0  -0.2  -0.3  -0.2  -0.2  -0.2  +0.1  +0.1  -0.1
K5EM       -0.1  +0.0  -0.0  -0.2  +0.0  -0.2  -0.1  -0.1  +0.0  +0.0
K5TR       +0.6  +0.5  +0.7  +1.0  +1.1  +1.0  +0.9  +1.1  +0.5  +0.4
K6FOD      +0.0  +0.2  +0.1  +0.2  +0.1  +0.2  +0.1  -0.2  +0.0  +0.1
K7EK       +0.1  +0.3  -0.0  -0.1  -0.0  +0.2  +0.3  +0.2  +0.2  +0.2
K7MJG      +0.1  +0.0  +0.1  +0.0  +0.4  +0.1  +0.3  +0.0  +0.4  +0.2
K9IMM      -0.1  -0.0  +0.0  -0.1  +0.0  -0.1  -0.0  -0.2  -0.1  +0.0
K9LC       -0.1  +0.1  +0.0  -0.1  -0.0  -0.0  -0.2  -0.1  +0.3  +0.4
KA7OEI     +0.1  +0.2  +0.2  +0.2  +0.2  +0.2  +0.1  +0.0  +0.0  +0.1
KC4YVA     +6.1  +6.1  +5.6  +5.2  +6.2  +5.1  +5.6  +4.9  +5.7  +5.3
KD2OGR     +0.2  +0.1  +0.2  +0.1  +0.2  +0.2  +0.3  +0.1  +0.1  +0.1
KH6LC      -0.2  -0.2  -0.1  +0.1  +0.0  -0.1  -0.1  -0.2  -0.0  -0.1
KL7RA      -2.1  -2.2  -2.3  -1.7  -0.8  -0.4  -0.7  -0.4  -0.8  +0.0
KM3T       -0.0  -0.0  -0.0  -0.2  +0.0  +0.1  -0.0  -0.0  -0.0  +0.0
KM3T-2     -0.4  -0.4  -0.3  -0.3  -0.2  -0.1  -0.2  -0.0  -0.1  -0.0
KM3T-3     +0.4  +0.1  -0.1  -0.2  -0.1  +0.0  -0.1  -0.1  -0.0  -0.1
KO7SS      -1.1  -1.0  -0.7  -0.8  -0.9  -0.9  -0.9  -1.2  -1.7  -1.1
KP3CW      +0.5  +0.8 +16.4 +16.5 +16.5 +16.4 +16.4 +16.5 +16.6 +15.7
KV4TT      +0.2  +0.1  -0.1  -0.0  -0.0  +0.0  +0.1  +0.1  +0.1  +0.0
LA6TPA     -3.5  -4.8  -6.6  -6.5  -6.1  -7.0  -8.2  -7.4  -7.4  -5.6
LZ3CB      -0.0  -0.1  -0.0  +0.0  +0.2  -0.0  -0.1  -0.1  +0.0  +0.0
LZ4AE      +2.5  +2.9  +1.0  +1.4  +1.5  +1.8  +2.0  +3.1  +3.0  +2.1
LZ4UX      -0.1  -0.1  -0.0  -0.1  -0.1  +0.0  +0.0  -0.0  -0.1  -0.0
LZ5DB                  +0.1  +0.0  -0.2  +0.3                        
LZ5DB-2                +3.9                                          
LZ5DI      +0.2  +0.2  +0.1  -0.0  +0.2  +0.2  +0.1  +0.2  +0.4  +0.2
LZ7AA      +0.6  +0.7  +0.4  +0.7  +0.8  +0.5  +0.5  +0.7  +0.8  +0.6
M0JYE           -13.7 -11.0 -14.2                    -9.3  -9.6 -12.6
MM0ZBH     -1.4  +3.6  +1.5  -1.2  +0.1  -0.4  -1.4  -0.4  -0.8  +1.3
MM3NDH     +0.0  +0.0  -0.0  +0.0  -0.1  +0.0  +0.0  +0.0  +0.0  +0.0
MW0MUT     -0.1  -0.1  -0.1  -0.0  -0.3  +0.0  -0.1  -0.2  -0.4  +0.0
N2QT       -0.5  -2.1  -2.0  +1.0  +1.6  +1.1  +1.5  +1.6  +0.9      
N4ZR       +0.4  +0.2  +0.0  -0.0  +0.1  +0.0  +0.1  -0.1  +0.1  +0.1
N6TV       +0.2  +0.0  +0.2  +0.5  +0.2  +0.3  +0.3  +0.2  +0.2  +0.2
N7TUG     +12.8 +12.0 +13.0 +13.5 +13.4 +14.0 +13.2 +13.4 +13.3 +13.8
N8DXE      +0.5  +0.8  +0.6  +0.6  +0.5  +0.3  +0.5  +0.9  +0.5  +0.3
N9CO       -0.2  +0.2  +0.0  -0.1  -0.0  -0.0  +0.0  +0.1  +0.0  +0.0
N9MKC      +0.2  +0.2  +0.0                                          
ND7K       -2.7  -2.5  -1.5  -1.1  -1.4  -1.4  -1.7  -2.2  -2.6  -1.8
NG7M       -0.8  -0.5  -0.3  -0.3  -0.3  -0.2  -0.3  -0.1  -0.2  -0.2
NH6HI      +4.7                                                      
NJ4P       +2.4  +3.2  +1.6  +2.4  +4.8  +4.1  +4.5  +2.3            
NN3RP      +0.0  +0.0  -0.2  -0.1  -0.4  +0.0  -0.1  -0.1  +0.3  +0.0
NU6XB      +0.2  +0.0  +0.4  +0.2  +0.6  +0.5  +0.4  +0.2  +0.3  +0.2
NX5M                               +5.8  +5.6  +5.7  +5.5  +5.7  +6.0
OE6ADD                             +0.9                              
OE6TZE     +0.0  +0.1  -0.0  +0.0  -0.0  +0.2  +0.0  +0.1  +0.2  +0.2
OE9GHV     -0.0  -0.1  -0.0  +0.1  -0.0  +0.0  -0.1  -0.1  +0.0  -0.0
OG66X      -0.9  -0.9  -0.5  -0.4  -0.0  -0.4  -1.3  -1.0  -1.2  +0.0
OG73X      -1.1  +0.5                                                
OH0K/6     -1.7  -1.8  -1.5  -0.6  -2.9  -1.4  -1.8  -1.7  -2.5  -1.4
OH2BBT           +1.9                                                
OH2J       -1.9  +3.8 +15.2 +14.0 +14.0 -15.3 -15.9 -13.7  -5.6  -7.0
OH4KA      -1.8  -2.3  -2.1  -2.5  -2.6  -3.2  -2.5  -2.3  -2.2  -1.6
OH6BG      +4.0  +3.1  +4.7  +2.8  +3.6  +3.4  +4.1  +5.2  +4.8  +4.9
OH8KA                  +1.2  +1.2  +1.6  +1.4  +1.3  +1.5  +1.4  +1.6
OK1FCJ     -0.0  +0.2  +0.1  +0.1  +0.2  +0.2  -0.1  -0.1  -0.0  -0.0
OK1HRA     -3.0  -3.5  -3.7  -3.6  -3.6  -3.3  -3.3  -3.8  -4.0  -3.8
OK4QRO     +1.5  +1.7              +0.0  +0.3  +0.2  +0.1  +0.1  +0.2
ON4EM      +0.0                                            +0.0      
ON6ZQ      -0.4  -0.8  -0.5  -0.6  -0.5  -0.5  -0.5  -0.9  -0.8  -0.5
ON7KEC           +2.5  +0.5  +0.6        +0.6                        
OZ1AAB     +0.1  +0.2  +0.1  +0.2  -0.2  +0.3  +0.1  +0.1  -0.7  -3.0
OZ1BZS     -0.0  -0.0  +0.1  +0.0  +0.0  +0.1  +0.2  +0.0  +0.0  -0.1
OZ1HDF     +0.2  +0.3                                      -2.0  +1.0
OZ4ADX     +0.1  +0.1  +0.0  -0.0  -0.2  +0.0  -0.0  -0.0  +0.1  -0.1
P40L       -0.1  -0.1  +0.1  -0.3  -0.1  +0.0  -0.0  -0.1  -0.2  -0.1
PA0MBO     +0.1  +0.3  +0.0  +0.1  +0.0  +0.5  -0.0  +0.1  +0.2  +0.2
PA2SQ                                                      +0.3  +0.7
PA5KT      -1.9  -2.0                                                
PA5WT                                    -0.5  -0.6              -0.5
PA8MM      -1.2  -0.6  -0.2  -0.4  -0.4  -0.4  -0.5  -3.1  -4.8  -2.4
PE5TT      -0.7  +0.0  -0.2  -1.0  -0.2  -0.2  -0.9  -0.7  -0.0  -0.7
PJ2A       +0.3  +0.4  +0.1  -0.4  -0.2  +0.2  -0.1  -0.0  -0.1  -0.0
R6YY       +0.1  +0.0  -0.0  +0.1  +0.2  +0.1  +0.2  +0.1  +0.3  +0.0
R9IR       -0.1  +0.0  +0.1  +0.0  -0.2  -0.1  -0.0  +0.6  +0.4  +0.3
RN4WA      +0.5  +0.4  +0.4  +0.4  -0.2  +0.3  +0.4  +0.6  +0.7  +0.6
RU9CZD     -2.0  -7.0 -13.6 -12.5  -9.8  -6.6  -4.8  -4.6  -1.5  -2.4
RW9AV      -0.3  -4.8  -1.1  -1.1  -0.9  -0.7  -1.1  -0.9  -1.0  -1.0
S50ARX                 +2.4  +2.9  +3.1  +2.9  +2.8  +3.1  +3.5  +3.2
S50U       +1.4  +1.9  +1.7  +1.8  +1.7  +1.8  +1.8  +1.8  +2.1  +1.4
S53A       -0.2  -0.1  -0.1  -0.3  -0.2  -0.1  +0.0  +0.2  +0.3  +0.5
SE5E       -0.5  -1.3  -1.6  -2.5  -2.6  -2.2  -1.4  -1.4  -1.2  -0.8
SM0TCZ     -1.5  -1.3  -2.5  -1.6  -1.2  -3.6  -0.5  -4.0  -4.9  -5.0
SM7IUN     -0.1  -0.2  -0.0  -0.1  +0.0  -0.0  -0.3  -0.0  +0.1  -0.1
SQ5J       +1.2  +1.5  +1.2  +1.5  +1.4  +1.5  +1.4  +1.5  +1.5  +1.3
SV1CDN     -1.0  -1.3  -0.4  -1.3  -1.3  -1.3  -0.8  -0.9  -0.6  -0.6
SV1DPJ                                               +0.8  +0.3  +0.1
SZ1A       +0.0  +0.5  -0.3  -0.7  -0.2  -0.2  -0.1  +0.6  +0.6  +0.4
TF3Y       +1.9  +2.0  +1.4  +1.7  +1.4  +2.0  +1.5  +1.5  +1.2  +1.5
TF4M       -0.9  -1.0  -1.2  -1.2  -0.9  -1.1  -1.0  -1.1  -1.5  -1.1
TI7W       -0.2  -0.2  -0.2  -0.2  -0.1  -0.1  -0.2  -0.1  -0.0  -0.0
TZ4AM                                    -3.0        -2.2            
UA0S       -3.1  -4.2  -5.4  -4.0  -2.9  -2.8  -2.8  -3.6  -3.6  -3.1
UY2RA      +0.8  +1.1  +0.8  +1.1  +1.1  +1.3  +1.1  +1.3  +0.9  +0.9
V51YJ      +2.1  +2.2  +1.6  +1.7  +1.9  +2.0  +2.2  +1.6  +1.4  +1.5
VE6AO      -2.0  -2.5  -1.5  -1.4  -1.1  -0.6  -1.3  -1.9  -1.8  -0.9
VE6JY      +0.8  +0.7  +1.0  +1.1  +1.4  +1.2  +0.9  +0.5  +1.4  +0.6
VE6WZ      +2.7  +3.3  +2.8  +2.3  +2.6  +1.8  +2.6  +2.4  +2.5  +2.5
VE7CC      +0.6  +0.6  +0.4  +0.7  +0.5  +0.4  +0.4  +0.3  +0.2  +0.3
VK2EBN           +0.0  +0.0                          +0.2            
VK2GEL                                         +0.4  -0.9  +2.9      
VK2RH      -0.3  +0.1  +0.0  +0.0  +0.3  +0.0  +0.0  +0.0  +0.1  +0.0
VK3RASA    +1.1  +0.2  +1.0  +0.8  -0.4  +0.3  +1.3  +1.4  +0.1  +0.2
VK6ANC     -1.1  -1.0  -0.9  -0.9  -0.9  -1.2  -0.8  -0.8  -0.6  -0.6
VP2VMM           +4.2  +4.7  +5.5                                    
VR2FUN-77  -1.0  -0.9  -0.9  -0.6  -0.8  -0.7  -0.7  -0.8  -0.6  -0.3
VY0ERC     +0.9  +0.6  +0.2  +1.2  +0.8              +0.5  +1.0      
W1NT-2     +0.5  +0.4  +0.3  +0.2  +0.4  +0.3  +0.3  +0.3  +0.3  +0.4
W1NT-6     +0.3  +0.2  +0.1  +0.1  +0.2  +0.2  +0.2  +0.2  +0.3  +0.2
W2AXR      +2.9                                                      
W2LB       +0.0                          +0.6  +1.6  +1.5  +1.5  +0.8
W2MV       +0.3  +0.1  +0.3  +0.1  +1.0  +0.3  +0.1  +0.3  +0.0  +0.3
W2NAF      +1.8  +1.6  +0.7  +0.9  +1.3  +1.0  +1.1  +1.1  +1.2  +1.1
W3DAN      +0.5  +0.7  +0.4  +0.5  +0.6  +0.3  +0.3  +0.8  +0.6  +0.2
W3LPL      -2.5  -2.6  -2.4  -2.6  -2.7  -2.5  -2.4  -2.5  -2.9  -2.3
W3OA       -0.1  -0.0  -0.1  -0.1  -0.0  -0.0  -0.0  -0.0  -0.2  -0.0
W3RGA      +0.1  +0.2  +0.0  -0.2  -0.1  -0.2  -0.1  +0.0  +0.0  -0.1
W3UA       -0.0  -0.0  -0.0  -0.0  -0.1  -0.0  -0.0  -0.0  -0.2  -0.0
W4AX       +3.3  +2.9  +3.1  +2.6  +4.5  +3.4  +3.0  +2.8  +3.0  +3.6
W4KAZ      -1.4  -2.6  -2.0  +0.0                    -0.0  -1.0  -2.8
W6BB       +0.3  +0.3  +0.2  +0.4  +0.5  +0.4  +0.7  +0.1  +0.3  +0.1
W6YX       -0.0  +0.1  -0.1  +0.1  +0.0  +0.1  +0.2  +0.1  +0.0  +0.0
W8WTS      -1.6  -1.7  -0.5  -1.0  -1.2  -0.8  -1.0  -0.7  -0.9  -0.6
W8WWV      -2.1  -2.0  -1.5  -1.6  -1.6  -1.5  -1.5  -1.7  -1.7  -1.3
WA7AI     +15.5 +14.9 +14.7 +15.3 +15.1 +15.3 +15.3 +16.7 +16.0 +14.1
WA7LNW     -2.0  -2.0  -0.8  -0.4  -0.6  -0.7  -1.0  -1.4  -2.2  -1.1
WB6BEE     +0.0  -0.0  -0.1  -0.0  -0.0  +0.0  +0.0  -0.0  -0.1  +0.1
WC2L       +0.5  +0.4  +0.2  +0.1  +0.5  +0.3  +0.6  +0.4        +0.5
WE7L                                                       +0.0      
WE9V       +2.4  +2.5  +6.6  +7.0  +6.5  +7.3  +6.7  +6.6  +5.5  +0.4
WF7U       -0.4  -0.5  -0.2  -0.3  -0.1  -0.4  -0.4  -0.3  -0.4  -0.1
WS3W       +0.2  +0.2  -0.4  -2.3  +0.9  -1.3  +0.7  +0.3  +1.0  +0.3
WZ7I       -0.0  -0.0  -0.0  -0.0  +0.0  +0.0  +0.0  -0.0  -0.0  +0.0
XV9Q       -0.1  -0.1                          +0.0  +0.0  +0.0      
YO4RDW     +0.5  +0.6  +0.5  +0.5  +0.5  +0.3  +0.2  +0.6  +0.6  +0.2
ZF1A             +0.9  +0.6  +0.8  +1.0  +0.9  +0.8  +0.9  +1.1      
ZF9CW      +0.2  -0.6  +0.1  +0.1  +0.1  -0.1  +0.2  +0.3  -0.1  -0.2
ZL2KS      -1.8  -1.8  -1.1  -1.7  -2.0  -2.6  -1.8  -1.2  -1.7  -1.5
ZL3X       -2.6        -2.2  -1.7  -1.7  -1.8  -2.5  -2.3  -1.3      
ZL4YL                              +0.9  +1.0  +1.2  +1.6  +1.1  +1.1

Last updated 2023-12-11 00:16:42 UTC

Anchor skimmers

The below skimmers use external frequency references and are confirmed to have continuous, high accuracy. Their accuracy is also confirmed against each other on a daily basis.

DF7GB ES2RR KM3T LZ3CB LZ4UX MM3NDH OE9GHV WB6BEE 

Last updated 2023-12-11 00:16:42 UTC

It is the owners of these skimmers who make this web page possible. Thank you.

To get good geographic coverage and a good size dataset, a two-step method is used for the analysis shown above. Since the second step also relies on spots from skimmers with slightly lower accuracy the displayed error for the anchor skimmers may not always be 0.0, even though they are perfectly accurate.

Software

The software powering this page can be found on github.