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 archived RBN data from the previous day, 00:00 to 23:59 UTC. This means that when making adjustments, changes in calibration will not have full impact on the listed data until the second day after the change.

The deviation estimates listed below are based on spots on all active bands (40m and above) 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 every night.

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 is 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.

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.

354147 RBN spots between 2022-10-05 00:00 and 23:59 UTC.
83270 spots (23.5%) were from reference skimmers (*).
Average spot flow was 246 per minute from 173 active CW skimmers.

154523 spots from 171 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 
  -------------------------------------
  3B8CW       -0.3    181   0.999999739
  3D2AG       +0.3    103   1.000000295
  3V8SS       -2.1   1221   0.999997903
  5W1SA       +1.2    122   1.000001184
  9M2CNC      +0.6    165   1.000000605
  BA6KC       +2.0     45   1.000002032
  BD8CS       +0.5    489   1.000000533
  BG4GOV      -0.6     51   0.999999441
  BG8DIV      -3.6    114   0.999996392
  BG8PA       -0.3     76   0.999999682
  BH4DEG      +1.3     34   1.000001327
  BH4RRG      +3.5    120   1.000003523
  BH4RRG0     -1.2    102   0.999998847
  BH4XDZ      -1.3     79   0.999998691
  BI4RFP      +0.3     84   1.000000298
  CX6VM       +2.5     62   1.000002475
  DD5XX       -0.4   1021   0.999999569
  DE1LON      +0.3   1742   1.000000345
  DE2SAX      -0.2   2046   0.999999835
  DF2CK       +2.0   2711   1.000001998
  DF7GB*      -0.0   1634   0.999999956
  DG6FL      -29.0     61   0.999971035
  DK0TE       +2.1   1532   1.000002099
  DK3UA       -0.5    333   0.999999467
  DK9IP*      +0.0   1290   1.000000011
  DL0LA       -0.3    865   0.999999651
  DL1AXX      -0.1    734   0.999999942
  DL1HWS*     +0.0   2153   1.000000038
  DL8LAS      +1.3   2227   1.000001268
  DM5GG*      +0.0   2297   1.000000029
  EA1RX       -6.8     91   0.999993207
  EA1URA*     +0.2   1701   1.000000234
  EA2CW*      +0.0   1712   1.000000003
  EA2NN       +0.0     13   1.000000000
  EA2RCF-4    +0.4    701   1.000000375
  EA5WU       -0.2    123   0.999999768
  EA8/DF4UE   +0.1   3312   1.000000140
  EA8BFK*     -0.1   1479   0.999999938
  ES2RR       +0.3   1725   1.000000346
  ET3AA       +0.1    235   1.000000101
  EY8ZE       +0.5    939   1.000000466
  F4VSQ       +4.7     19   1.000004696
  F6IIT       -1.1   2585   0.999998945
  F8DGY       +0.7     94   1.000000674
  G0KTN       +0.4   1725   1.000000427
  G3XBI       +0.1     42   1.000000113
  G4HSO       -0.6   2225   0.999999391
  G4ZFE*      -0.1   2005   0.999999886
  GI4DOH      +0.6    366   1.000000603
  GM6DX       +0.0     17   1.000000000
  HA1VHF      -0.5   1632   0.999999479
  HA6PX       -2.9    487   0.999997107
  HA7GN       +0.6    256   1.000000584
  HA8TKS*     +0.1   1059   1.000000116
  HB9BXE      +0.2   1636   1.000000213
  HB9CAT      +3.8   1508   1.000003778
  HB9DCO*     -0.1   1706   0.999999941
  HG8A        -0.4   2027   0.999999595
  HS8KVH      +5.1    116   1.000005109
  IK3STG      +5.7   1442   1.000005740
  IK4VET      +0.3   2648   1.000000332
  JA4ZRK      -0.4     13   0.999999575
  JH7CSU1     +4.4    181   1.000004373
  JI1HFJ      -2.2     38   0.999997789
  JJ2VLY      +0.5     99   1.000000513
  JK4USW      +1.2     46   1.000001240
  JN1ILK      -0.7    357   0.999999305
  JQ1BVI      -0.2    124   0.999999844
  K1TTT       -0.5   3852   0.999999454
  K3PA-1      +0.6   1187   1.000000573
  K4PP        -0.2    764   0.999999761
  K5TR        +1.3   1078   1.000001344
  K7EG        +1.5    434   1.000001453
  K7EK       -10.3    322   0.999989750
  K7MJG       +0.2    194   1.000000183
  K9IMM       +0.8     54   1.000000800
  K9LC        +0.2    234   1.000000250
  KC4YVA      +5.1    847   1.000005080
  KD2OGR*     +0.1   1039   1.000000108
  KG7V        +0.2    283   1.000000154
  KH6LC       -0.4     76   0.999999636
  KM3T*       -0.0   2284   0.999999987
  KM3T-2      +0.5   2923   1.000000507
  KO7SS       -0.3   1378   0.999999704
  KP2RUM      +0.3   1125   1.000000284
  KV4TT*      +0.0   1388   1.000000039
  LA6TPA      +0.8    493   1.000000809
  LA7GIA      +0.0     31   1.000000000
  LY3G        +0.9     47   1.000000860
  LZ3CB*      -0.0    933   0.999999980
  LZ4AE       +2.0   1948   1.000002036
  LZ4UX*      -0.1   1264   0.999999942
  LZ7AA       +0.4   1597   1.000000379
  M0NPT*      -0.1   1594   0.999999871
  MM3NDH*     -0.0   1115   0.999999972
  N4RLI       -1.9    746   0.999998095
  N4ZR        -0.5   1229   0.999999503
  N6TV        +0.4    526   1.000000447
  N6WIN-7     +0.4   1249   1.000000427
  N7TUG       +8.4     80   1.000008361
  NA0B        -0.1    289   0.999999852
  NC7J        +1.1    695   1.000001135
  NN3RP*      +0.1    782   1.000000078
  OE9GHV*     +0.0   2402   1.000000005
  OG66X       -0.4   1548   0.999999595
  OH4KA       +0.7    991   1.000000679
  OH8KA       -2.5    212   0.999997530
  OK1FCJ*     -0.0   1896   0.999999980
  ON6ZQ       -0.5   1168   0.999999533
  PA0MBO      +1.5    619   1.000001531
  PA8MM       -5.9    806   0.999994059
  PJ2A        -0.5    380   0.999999473
  R6YY        +0.5    855   1.000000488
  R9IR        +0.2    131   1.000000199
  RK3TD*      -0.2   1500   0.999999847
  RN4WA       -0.6    197   0.999999422
  RU9CZD      +3.6    426   1.000003623
  S53WW       -0.4   2262   0.999999645
  S55OO       +0.0     52   1.000000000
  SE5E*       +0.1   2282   1.000000112
  SM0TCZ      +2.4    138   1.000002373
  SM6FMB      +1.3   1068   1.000001296
  SM7IUN*     +0.0   1824   1.000000049
  SP8R        -6.2    592   0.999993787
  SV1CDN      +1.0    254   1.000001038
  SV8RV       +0.3    573   1.000000305
  TF3Y        +0.9   1173   1.000000920
  TF4M        -1.3    234   0.999998735
  TI7W        +0.7   1953   1.000000702
  UA0S        -3.7   1138   0.999996265
  UA3REO      +0.0    287   1.000000017
  UP2L        -3.6    397   0.999996352
  V51YJ       +1.6    160   1.000001578
  VE2WU       -2.2    532   0.999997843
  VE3NZ       +3.0    692   1.000003042
  VE6AO       -1.0    303   0.999999001
  VE6JY       +0.8    814   1.000000813
  VE6WZ       +2.3    747   1.000002251
  VE7CC       +0.5    628   1.000000481
  VK2GEL      +1.0     41   1.000000985
  VK3RASA    -10.6     99   0.999989405
  VK4CT       -1.7    395   0.999998322
  VK6ANC      -2.3    164   0.999997716
  VU2PTT      -1.0     90   0.999998965
  VY0ERC      -1.1     21   0.999998891
  W1NT-2      -6.9    384   0.999993141
  W1NT-6      -0.4   2713   0.999999556
  W2AXR       +0.3   1320   1.000000348
  W2LB        +1.1    172   1.000001074
  W2MV        +0.2    200   1.000000213
  W2NAF       +1.1   1988   1.000001110
  W3LPL       +1.3   2304   1.000001260
  W3OA        +0.2    347   1.000000226
  W3RGA       +0.1   1433   1.000000085
  W3RGA-1     +0.1   1224   1.000000106
  W3UA*       -0.0   2592   0.999999983
  W4AX        +5.0    459   1.000005006
  W4KAZ       -1.3    666   0.999998746
  W6YX        +1.9    694   1.000001859
  W8WTS       -1.2   1361   0.999998793
  W8WWV       -2.1   1646   0.999997908
  WA7AI       +1.0    424   1.000000978
  WA7LNW      +0.5    425   1.000000548
  WC2L        -0.6   1523   0.999999362
  WE9V*       -0.2   1695   0.999999807
  WF7U        +1.4    398   1.000001374
  WS3W        +1.0   1407   1.000000991
  WZ7I*       +0.1   2596   1.000000119
  YU7GM       +0.8     89   1.000000800
  ZF1A        +1.1     84   1.000001149
  ZL2KS       -3.7     75   0.999996338

Last updated 2022-10-06 00:15:30 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    1005  1004  1003  1002  1001  0930  0929  0928  0927  0926
---------------------------------------------------------------------
3B8CW      -0.3  -0.3  -0.2  -0.3  -0.6  -0.2  -0.5  -1.0  -1.0  -0.3
3D2AG      +0.3  +0.7  +0.3  +0.2  +0.1  +0.0  -0.1  +0.2  +0.0  +0.2
3V8SS      -2.1  -1.9  -1.9  -2.1  -2.1  -2.0  -2.5  -1.9  -2.2  -2.8
5W1SA      +1.2  +0.6  +0.9  +0.8  +0.8  +0.6  +0.7  +0.9  +0.3  +1.0
9M2CNC     +0.6  +0.2  +0.7  +0.9  +0.4  +0.9  +0.7  +1.1  +0.7  +0.9
AA4VV            -0.1                                                
BA6KC      +2.0  +3.4  +4.1  +2.4  +2.0  +1.9  +2.2  +2.0  +2.3  +2.1
BD7JNA                             +0.3        +0.6  -0.0            
BD8CS      +0.5  +0.7  +0.7  +0.6                                    
BG4GOV     -0.6  -0.2  -0.4  +0.6  -0.3  -0.4  -1.0  +0.2  +0.0      
BG4GOV-3               +7.1  +5.9  +4.0  +6.0  +2.4                  
BG4WOM                 +0.9  +0.4  +0.1                              
BG8DIV     -3.6  -4.4  -3.3  -2.9  -2.7  -2.4  -2.5  -2.6  -2.0  -3.3
BG8PA      -0.3  +0.0  -0.2  -0.0  +0.1  -0.4  +0.0  +0.1  -0.2  +0.0
BH3FAL                       +2.5  -0.5  +2.5  +4.1  -4.2        +2.6
BH4DEG     +1.3  +4.4  +7.2  +5.5  +4.5  +5.8  +4.9  -0.6  +4.3  +3.6
BH4RRG0    -1.2  -0.1  +0.8  +0.2  +0.1  -0.5  -0.3  +0.0  -1.3      
BH4RRG     +3.5  +0.7  +2.5  +3.2  +2.6  +4.9  +1.8  +3.0  +6.9  +8.0
BH4XDZ     -1.3  -0.1  +0.5  -0.2  -0.0  +0.0  +0.2  +0.1  -0.8  +0.0
BI4RFP     +0.3  -0.7  -0.2  -0.4                    +8.6  +7.4 +13.2
BI4RFP-1                     +0.3  +4.2  +4.8  +3.1  +4.3            
BI4RFP-2                     -0.2 +11.2 +11.7  +4.7 +12.8            
CX6VM      +2.5  +1.8  +1.9  +2.2  +2.2  +2.0  +1.0  +0.8  +2.4  +1.7
DD5XX      -0.4  -0.7  -0.8  -0.9  -1.3  -0.7  -1.2  -1.2  -1.2  -1.0
DE1LON     +0.3  +0.2  +0.1  -0.0  +0.1  +0.1  +0.0  -0.0  -0.1  +0.1
DE2SAX     -0.2  -0.1  -0.1  +0.0                                    
DF2CK      +2.0  +2.2  +2.2  +1.5  +1.3  +1.7  +1.4  +1.1  +1.5  +2.1
DF2CK-3          +0.0              -0.1                          -0.2
DF7GB      -0.0  +0.0  -0.1  -0.0  +0.0  +0.0  +0.0  +0.1  +0.0  +0.0
DG6FL     -29.0 -29.2 -30.0 -29.6 -28.9 -28.5 -29.3 -29.0 -28.5 -29.1
DJ2BC            -0.8  -0.5  -0.7  -0.5  -0.3  -0.5  -0.4  -0.5  -0.6
DK0TE      +2.1  +1.8  +2.8  +2.8  +2.3  +2.3  +2.5  +2.0  +2.0  +1.9
DK0VLP                                                           -1.1
DK3UA      -0.5  -0.4  -0.8  -0.6  -0.2  -0.3  -0.3  -0.2  -0.5  -0.3
DK3WW                                          +0.0  +0.0  +0.2  +0.3
DK9IP      +0.0  -0.0  +0.0  -0.0  -0.0  -0.1  -0.1  -0.1  +0.1  -0.0
DL0LA      -0.3  -0.3  -0.3  -0.2  +0.5  +0.5  +0.7  +0.6  +0.8      
DL1AXX     -0.1  -0.1  +0.0  -0.2              +0.0  +0.0  -0.1  -0.1
DL1HWS     +0.0  +0.1  +0.2  +0.2  +0.1  +0.2  +0.2  +0.2  +0.2  +0.2
DL8LAS     +1.3  +1.3  +1.4  +1.4  +1.0  +0.7  +1.0  +1.0  +1.1  +1.2
DL8TG                                          +0.0  -0.4  -0.4  -0.3
DL9GTB           +0.1  -0.0        +0.1  +0.4                        
DM5GG      +0.0  -0.1  -0.0  -0.0  -0.0  -0.0  -0.1  -0.1  -0.1  +0.0
DM6EE            +0.1  +0.1  +0.0  +0.1  +0.1  +0.1  +0.1  +0.1  +0.1
DO4DXA                                   +0.0  +0.0  +0.0  -0.3      
EA1RX      -6.8  -7.7  -8.7 -10.3  -7.0  -7.0  -8.7  -8.2 -11.7  -9.5
EA1URA     +0.2  +0.4  +0.2  +0.2  +0.4  -0.1  -0.3  -0.2        -0.2
EA2CW      +0.0  -0.1  -0.1  -0.2  -0.3  -0.2  -0.2  -0.2  -0.2  -0.2
EA2NN      +0.0                          -0.2  -0.5  +0.0            
EA2RCF-4   +0.4  +0.2  +0.1  -0.2  -0.3  -0.2  -0.1  -0.2  -1.2  -0.8
EA5WU      -0.2  +0.0  -0.1  -0.1  -0.2  -0.7  -0.2  -0.2  -0.2  -4.8
EA8BFK     -0.1  -0.2  -0.1  -0.1  -0.1  -0.0  -0.1  -0.2  -0.2  -0.0
EA8/DF4UE  +0.1  +0.2  +0.3  +0.4  +0.4  +0.4  +0.7  +1.4  +1.1      
ES2RR      +0.3  -0.2  +0.5  +0.1  +0.2  -0.0  +0.2  -0.1  +0.4  +0.3
ET3AA      +0.1  -0.1  -0.2  -0.0  -0.1  +0.1  +0.2  +0.5  +0.1  -0.1
EU1ST            +4.7  +3.5  +3.6  +2.1  +3.4  +2.6  +0.9            
EY8ZE      +0.5  +0.3  +0.4  +0.7  +0.4                              
F4VSQ      +4.7  +4.9  +4.3  +4.1  +3.8  +9.6  +9.1  +5.3  +5.3  +4.8
F6IIT      -1.1  -1.2  -1.1  -1.3  -1.2  -1.5  -2.1  -1.1  -2.4  -1.8
F8DGY      +0.7        +0.5  +0.6        +0.5  +0.5  +0.7  +0.7  +0.4
G0KTN      +0.4  +0.5  +0.5  +0.6  +0.5  +0.3  +0.3  +0.4  +0.4  +0.5
G0TMX                              +0.8                              
G1VWC            +0.0                                                
G3XBI      +0.1  -0.0  +0.2  +0.1  +0.0  +0.4  +0.5  +0.2  +0.0  +0.0
G4AON            +1.0                    +1.0  +0.9  +0.5  +1.2  +1.3
G4HSO      -0.6  -0.5  -1.0  -0.5  -0.5  -0.6  -0.6  -0.7  -0.6  -0.4
G4ZFE      -0.1  -0.1  -0.2  -0.3  -0.4  -0.1  -0.2  -0.2  -0.1  -0.1
GI4DOH     +0.6  +0.6  +0.5  +0.8  +0.6  +0.4  +0.6  +0.7  +0.4  +0.7
GM6DX      +0.0  +0.6  +0.3                    -0.1  +0.8  +0.3  +0.6
HA1VHF     -0.5  -0.4  -0.6  -0.8  -0.8  -0.6  -0.7  -0.6  -0.5  -0.5
HA5PP-2                      +1.0  +0.2  -0.0                        
HA5PP                        +4.4  -0.6  -0.2                        
HA6PX      -2.9  -3.0  -3.5  -3.1  -2.4  -2.3  -2.4  -3.1  -2.8  -2.6
HA7GN      +0.6  +1.2  +0.6  +0.9  +0.5  +0.6  +0.5  +0.9        +0.9
HA8TKS     +0.1  +0.2  +0.2        +0.1  +0.1  +0.0  +0.1  +0.2  +0.2
HB9BXE     +0.2  +0.1  +0.2  +0.1  +0.0  +0.1  +0.2  +0.0  +0.0  +0.1
HB9CAT     +3.8  +4.2  +4.3  +4.5  +4.1  +3.7  +4.0  +4.0  +4.0  +4.0
HB9DCO     -0.1  -0.1  -0.0  -0.0  +0.1  +0.1  +0.2  +0.2  +0.1  +0.1
HG8A       -0.4  -0.4  -0.2  -0.2  -0.2  +0.0  -0.3  -0.2  -0.4  -0.3
HS8KVH     +5.1  +6.1  +6.0  +5.4  +5.6  +5.4  +5.4  +5.5  +3.9      
HS/F8UKP         -0.3  -0.4  -0.2  -0.2  -0.3  -0.3  -0.6  -0.3  -0.8
IK3STG     +5.7  +5.9  +6.2  +6.3  +6.2  +6.1  +6.4  +6.2  +6.4  +6.7
IK4VET     +0.3  +0.3  +0.3  +0.2  +0.2                              
JA4ZRK     -0.4  +0.0  +0.0  -0.3  -0.0  +0.0  -0.1  +0.0  -0.4  +0.3
JH7CSU1    +4.4  +5.0  +5.8  +4.4  +3.7  +4.2  +4.3  +3.5  +4.2  +4.7
JI1HFJ     -2.2  -2.6  -2.1  -2.5  -5.5  -4.0  -2.8  -3.4  -3.0  -3.1
JJ2VLY     +0.5  +1.3  +0.8  +1.5  +1.5  +0.7  +1.1  +1.6  +0.9  +1.8
JK4USW     +1.2  +0.6  +0.5  +1.5  +0.6  +0.9  +0.8  +1.3  +0.9  +1.8
JN1ILK     -0.7  -0.2  -0.7  -0.6  -0.4  -0.3  -0.1  -0.2  -0.2  +0.2
JQ1BVI     -0.2  -0.3  -0.1  -0.2  +0.0  -0.1  -0.0  -0.0  +0.1  -0.0
K1TTT      -0.5  -0.5  -0.5  -0.4  -0.4  -0.5  -0.4  -0.4  -0.6  -0.3
K3PA-1     +0.6  +0.2  +0.4  +0.4  +0.4  +0.6  +0.7  +0.3  +0.1  +0.1
K4PP       -0.2  -0.2  +0.0  -0.0  -0.1  -0.1  -0.4  -0.8  -0.0  -0.2
K5TR       +1.3  +0.9  +0.8  +0.6  +0.5  +0.5  +1.2  +1.7  +0.8  +1.3
K7EG       +1.5  +0.7  +1.1  +1.7  +1.7  +0.9  +1.4  +2.0  +0.5  +1.2
K7EK      -10.3 -10.3 -10.7  -9.8  -8.8 -10.1 -11.7  -9.8 -10.8  -9.6
K7MJG      +0.2  +0.3  +0.2  +0.1  +0.1  +0.4  +0.5  +0.6  +0.3  +0.3
K9IMM      +0.8  +0.4  +0.3  +0.3  +0.2  -0.3  +0.1  +0.2  +0.1  +0.2
K9LC       +0.2  +0.2  +0.1  +0.1  +0.1  +0.1  +0.0  +0.1  +0.2  +0.4
K9TM-4                                               +1.2  +0.8  +1.0
KC4YVA     +5.1  +4.5  +4.4  +5.1  +5.2  +4.6  +4.3  +4.7  +4.3  +4.5
KD2OGR     +0.1  +0.1  +0.2  +0.1  -0.0  +0.1  -0.1  -0.0  -0.1  +0.1
KG7V       +0.2  +0.1  +0.3  +0.5  +0.8  +0.4  +0.2  +0.4  +0.0  +0.6
KH6LC      -0.4  +0.4  -0.2  +0.1  -0.0  +0.0  +0.3  +0.3  -0.1  +0.5
KM3T       -0.0  -0.0  +0.0  -0.1  +0.0  -0.0  +0.0  -0.1  +0.0  +0.0
KM3T-2     +0.5  +0.5  +0.4  +0.6  +0.6  +0.3  -0.1  +0.1  +0.1  +0.1
KO7SS      -0.3  +0.0  +0.1  +0.0  -0.1  +0.0  +0.2  +0.4  +0.2  +0.5
KP2RUM     +0.3  +0.1  +0.2  +0.1  +0.2  +0.2  +0.2  +0.2  +0.1  +0.3
KV4TT      +0.0  -0.1  -0.2  -0.0  +0.4  +0.1  +0.0  +0.3  +0.4  +0.2
LA6TPA     +0.8  +0.9  +0.8  +1.0  +1.1                              
LA7GIA     +0.0  -0.2  -0.1  -0.2  -0.1  +0.7  -0.1  +0.1  +0.0  +0.4
LY3G       +0.9  +0.6                                                
LZ3CB      -0.0  -0.0  +0.0  -0.0  -0.1  -0.0  -0.1  -0.0  -0.1  +0.0
LZ4AE      +2.0  +2.2  +2.6  +2.9  +2.4  +2.3  +2.4  +2.4  +2.1  +2.4
LZ4UX      -0.1  -0.1  -0.0  -0.3  -0.1  +0.0  +0.1  +0.0  -0.2  +0.0
LZ7AA      +0.4  +0.5  +0.6  +0.8  +0.7  +0.6  +0.7  +0.5  +0.4  +0.7
M0NPT      -0.1  -0.1  -0.2  -0.2  -0.2  -0.1  -0.2  -0.2  -0.2  -0.2
MM0ZBH                                   -0.1  -0.1  -0.4  -0.5  -0.3
MM3NDH     -0.0  -0.0  -0.1  -0.0  -0.1  -0.1  -0.1  -0.1  -0.0  -0.0
MW0MUT                                                           +1.1
N4RLI      -1.9  -1.7              -0.8  -1.3  -1.5  -1.5  -0.9  -0.9
N4ZR       -0.5  -0.5  -0.4  -0.6  -0.0  -0.2  -0.2  -0.5  -0.1  +0.1
N6TV       +0.4  +0.4  +0.5  +0.2  +0.4  +0.5  +0.6  +0.5  +0.3  +0.7
N6WIN-7    +0.4  +0.3  +0.4  +0.5  +0.4  +0.3  +0.4  +0.4  +0.3  +0.4
N7TUG      +8.4  +8.3  +9.3  +8.4  +8.5  +9.2  +8.3  +9.9  +9.1  +8.7
NA0B       -0.1  +0.1  -0.2  -0.0  -0.2  +0.5  +0.0        -0.8  +0.1
NA0B/A                                         -0.0  -0.7            
NC7J       +1.1  +0.6  +0.8  +1.0  +0.7  +0.6  +1.0  +1.1  +0.6  +0.8
NH6HI                  +4.7  +7.1                                    
NN3RP      +0.1  +0.1  +0.0  +0.1  +0.2  +0.2  +0.2  +0.3  +0.4  +0.5
NR4U                         -0.8  -1.1  -0.9  -0.3  -0.3  -0.4  -0.5
NT6Q             +1.1  +1.0              +0.3  +0.6  +0.7  +0.8  +0.8
OE9GHV     +0.0  -0.1  +0.0  +0.0  -0.1  -0.0  +0.0  -0.0  +0.0  -0.0
OG66X      -0.4  -0.4  -0.5  -0.5                    -0.8  -0.6      
OH4KA      +0.7  +0.5  +0.5  +0.7  +0.5  +0.5  +0.4  +0.7  +0.8  +0.9
OH6BG            +5.3  +2.6  +3.1  +3.7  +3.2  +2.8  +2.7  +2.9  +2.8
OH8KA      -2.5  -2.7  -3.7                    +0.3  +0.4  +0.4  +0.4
OK1FCJ     -0.0  +0.0  +0.1  -0.1  -0.1  +0.0  +0.0  -0.1  -0.1  +0.0
OK2ZAW           -0.7  -0.8  -0.8  -0.2        -0.7  -0.6        -0.3
ON6ZQ      -0.5  -0.2  +0.1  -0.2  -0.2  -0.2  -0.8  -0.6  -0.6  -0.6
PA0MBO     +1.5  +0.2  -0.0  +0.1  -0.1  -0.2  -0.0  -0.1  -0.3  +0.3
PA8MM      -5.9                                                      
PJ2A       -0.5  -0.1  +0.4  +0.1  +0.1  +0.1  +0.3  +0.2  -0.0  +0.2
R6YY       +0.5  +0.1  +0.2  +0.3  +0.2  +0.4  +0.2  +0.1  -0.2  +0.1
R9IR       +0.2  +0.4  -0.2  +0.0  +0.1  +0.2  +0.2  -0.0  -0.1  +0.1
RK3TD      -0.2  -0.2  -0.2  -0.2  -0.2  +0.0  -0.1  -0.1  -0.3  -0.1
RN4WA      -0.6  -0.3  -0.3  -0.4  -0.3  -0.2  -0.2  -0.3  -0.5  -0.3
RU9CZD     +3.6  +3.7  +4.5  +4.5  +4.0  +3.7  +3.1  +3.1  +3.2  +3.7
RW9AV                        -1.2  -1.3  -0.9  -1.3  -1.2  -1.8  -1.0
S53WW      -0.4  -0.4  -0.3  -0.4  -0.2  -0.3  -0.4  -0.4  -0.3  -0.2
S55OO      +0.0  -0.1  -0.5  -0.3  -0.2  -0.5                        
SE5E       +0.1  -0.0  +0.1  +0.0  -0.0  +0.1  +0.0  +0.1  +0.1  +0.1
SM0TCZ     +2.4  +1.6  +2.4  +2.5  +0.4  +2.0  +1.7  +1.1  +1.6  +2.2
SM6FMB     +1.3  +0.9  +1.6  +1.4        +1.2  +1.4  +1.4  +1.3  +1.4
SM7IUN     +0.0  +0.0  +0.2  +0.0  +0.0  -0.0  -0.0  -0.0  -0.2  -0.0
SP8R       -6.2  -6.6  -6.6  -6.6  -6.4  -6.3  -6.6  -6.4  -6.7  -6.4
SV1CDN     +1.0  +1.0  +1.3  +1.3  +2.4  +2.0  +1.5  +2.0  -0.4  -0.4
SV8RV      +0.3  +0.3  +0.3  +0.0  +0.0  +0.2  +0.2  +0.2  +0.1  +0.3
TF3Y       +0.9  +1.1  +1.1  +1.0  +0.4  +0.7  +0.9  +1.1  +0.9  +1.0
TF4M       -1.3                                                      
TI7W       +0.7  +0.6  +0.8  +0.8  +0.8  +0.7  +0.7  +0.7  +0.6  +0.8
UA0S       -3.7  -3.6  -4.0  -4.3  -7.0  -3.5  -4.4  -5.0  -8.2  -3.2
UA3REO     +0.0  +0.9  +0.7  +0.3  +0.8  +0.5  +1.0  +1.0  +1.1  +1.0
UA4M                         +2.7  +3.2  +4.3  +4.5  +4.0  +3.9  +4.4
UP2L       -3.6  -3.4  -3.9  -4.1  -3.8  -3.6  -3.3  -3.4  -3.3  -3.7
V51YJ      +1.6  +1.6  +1.3  +1.5  +1.8  +1.1  +1.8  +1.6  +1.1  +1.2
VE2WU      -2.2  -0.0  -0.4  -1.3  +0.2  +0.1  +0.1  +0.5  +0.4  +4.5
VE3NZ      +3.0  +2.1  +0.8                                          
VE6AO      -1.0  -0.7  -0.5  -1.1  -0.9  -1.2  -0.6  -1.0  -0.7  -0.6
VE6JY      +0.8  +0.7  +0.9  +1.3  +0.6  +0.6  +1.3  +1.2  +0.6  +0.9
VE6WZ      +2.3  +1.7  +2.0  +2.0  +2.2  +1.0  +1.3  +1.8  +1.6  +2.5
VE7CC      +0.5  +0.3  +0.4  +0.5  +0.3  +0.2  +0.6  +0.4  -0.2  +0.4
VK2EBN                       +0.3  +0.0                              
VK2GEL     +1.0  +3.0  +1.6  +3.6  +3.7  +2.8  +2.2  +0.7  +3.7  +3.2
VK3RASA   -10.6  -9.9        -9.9  -9.8  -9.9  -9.0 -10.2  -9.5  -9.6
VK4CT      -1.7  -2.7  -1.6  -2.4  -2.1  -0.4  -1.8  -1.2  -1.2  -0.2
VK6ANC     -2.3  -0.9  -0.8  -1.5  -1.2  -0.8  -0.7  -0.9  -1.9  -1.8
VU2PTT     -1.0  -1.6  -1.5  -0.8  -1.9  -1.2  -0.5  -1.4  -1.2  -1.3
VY0ERC     -1.1  -0.6        -1.4  -0.9  -2.5  -0.9  -1.7        -1.5
W1NT-2     -6.9  -6.9  -7.3  -7.0  -6.7  -6.5  -5.9  -5.8  -5.9  -6.8
W1NT-6     -0.4  -0.4  -0.3  -0.3  -0.3  -0.2  -0.0  -0.0  -0.0  -0.2
W2AXR      +0.3                                                      
W2LB       +1.1  +1.1  +0.9  +1.9  +1.7  +0.6  +1.6  +1.7  +1.9  +1.3
W2MV       +0.2  +0.0  +0.0  +0.2  +0.1  +0.1  +0.6  +0.7  +0.3  +0.9
W2NAF      +1.1  +0.9  +1.0  +1.4  +1.3  +0.8  +1.1  +1.3  +0.9  +1.0
W3LPL      +1.3  +1.3  +1.1  +1.5  +1.5  +1.2  +1.3  +1.4  +1.0  +1.3
W3OA       +0.2  +0.2  +0.2  +0.2  +0.2  +0.1  +0.3  +0.3  +0.6  +0.4
W3RGA      +0.1  +0.1  -0.1  +0.2  +0.2  +0.0  +0.1  +0.0  -0.0  +0.1
W3RGA-1    +0.1  +0.0  -0.1  +0.2  +0.3                              
W3UA       -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.1  -0.0
W4AX       +5.0  +3.9  +4.2  +4.6  +4.4  +4.3  +5.6  +4.9  +4.6  +5.1
W4KAZ      -1.3  -1.3  -1.2  -1.4  -1.3  -1.0  -0.7  -0.7  -0.5  -0.2
W6YX       +1.9  +1.4  +1.4  +1.9  +1.8  +1.6  +1.5  +1.7  +1.1  +1.6
W8WTS      -1.2  -1.1  -1.0  -1.1  -1.1              -0.8  -0.7  -0.5
W8WWV      -2.1  -1.8  -1.8  -2.1  -2.0  -1.7  -1.7  -1.8  -1.4  -1.5
WA7AI      +1.0  +1.1  +1.6  +1.4  +1.2  +0.7  +0.9  +0.9  +1.5  +1.2
WA7LNW     +0.5  +0.5  +0.4  +0.8  +0.7  +0.5  +0.5  +1.0  +0.7  +0.6
WB6BEE           +0.0  +0.1  -0.0  -0.0  +0.1  -0.0  +0.0  +0.0  -0.1
WC2L       -0.6  -0.6  -0.7  -0.7  -0.7  -0.6  -0.5  -0.4  -0.2  -0.3
WE9V       -0.2  -0.2  -0.3                                          
WF7U       +1.4  +0.7  +1.6  +1.8  +1.2  +0.8  +0.7  +1.9  +1.1  +1.2
WS3W       +1.0  -0.4  -0.1  +1.4  +2.1  +0.4  +0.1  +1.4  -0.1  +0.8
WW1L             -5.8  -5.0  -5.2  -4.4  -4.7  -4.6  -4.4  -5.3  -3.2
WZ7I       +0.1  +0.1  +0.1  +0.1  +0.0  +0.1  +0.2  +0.1  +0.1  +0.2
YU7GM      +0.8                    +1.4  +0.3  +0.4  +0.8        +5.2
ZF1A       +1.1  +0.6  +2.0  +2.6              +1.0                  
ZL2KS      -3.7  -4.3  -3.8  -4.7  -4.9  -5.7  -3.3  -5.2  -5.7  -4.6

Last updated 2022-10-06 00:15:37 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 KM3T LZ3CB OE9GHV 

Last updated 2022-10-06 00:15:37 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.