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. This is also the reason for not including spots under a certain frequency. They will just 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.

1744324 RBN spots between 2023-02-05 00:00 and 23:59 UTC.
372054 spots (21.3%) were from reference skimmers (*).
Average spot flow was 1211 per minute from 192 active CW skimmers.

837151 spots from 190 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*      +0.0    634   1.000000012
  3D2AG       -0.2    546   0.999999760
  5W1SA       +1.3    444   1.000001324
  7N4XCV      +2.0     89   1.000001996
  9M2CNC      -0.3    361   0.999999717
  AA4VV*      +0.0   8123   1.000000009
  AC0C-1      -0.1   8132   0.999999888
  BA6KC       +2.6    410   1.000002582
  BD4QJP      +0.8     52   1.000000787
  BD7DT       +0.3   1559   1.000000262
  BD7JNA      -0.6    100   0.999999358
  BG4GOV      +0.1    190   1.000000134
  BG4GOV3     +4.7     28   1.000004731
  BG4WOM      -6.1    685   0.999993925
  BG8FZU      -0.9   1331   0.999999123
  BH3BBJ      +0.2    831   1.000000174
  BH4DEG      +3.3    167   1.000003280
  BH4RRG      +0.3    217   1.000000319
  BH4RRG0     +2.0    559   1.000002028
  BH4XDZ      +0.5    279   1.000000504
  BH4XDZ-1    +1.0    272   1.000000960
  BI4MPH      +8.9     12   1.000008898
  BI4RFP-1    +1.3    421   1.000001302
  CX6VM       -1.8   1648   0.999998197
  DC8YZ*      +0.0  12107   1.000000039
  DD5XX*      -0.0   6277   0.999999993
  DE1LON      -0.9   9893   0.999999064
  DE2SAX      -0.7   2185   0.999999348
  DF2CK*      -0.1  13721   0.999999927
  DF7GB*      +0.0  11681   1.000000002
  DG6FL      -28.7     46   0.999971321
  DK0TE      +16.7   8396   1.000016676
  DK9IP       -0.2   6950   0.999999842
  DL0LA*      -0.0   6076   0.999999967
  DL0PF       +1.2   8785   1.000001204
  DL1HWS      +0.3   9887   1.000000288
  DL8LAS      +1.2   7001   1.000001180
  DL8TG*      -0.1   9916   0.999999934
  DL9GTB      -0.7   8411   0.999999285
  DM5GG       +0.3  10685   1.000000298
  DM6EE*      +0.1   5019   1.000000058
  DO4DXA*     -0.1   6100   0.999999890
  DP7D        +0.0     13   1.000000000
  EA1DAV      -0.8  11261   0.999999237
  EA1RX       -6.2    299   0.999993781
  EA1URA*     +0.1   8230   1.000000132
  EA2CW       -0.3   1992   0.999999717
  EA2RCF-4*   +0.0   7177   1.000000041
  EA5WU       -0.7  10256   0.999999293
  EA8/DF4UE   -0.5  15217   0.999999517
  ES2RR       -1.4   9220   0.999998626
  EY8ZE       -1.2   3613   0.999998759
  F4VSQ       +3.8    428   1.000003760
  F6IIT       -1.4   4973   0.999998553
  F8DGY*      +0.0   2960   1.000000014
  G0KTN       +0.3   9236   1.000000276
  G0TAI       -0.4    922   0.999999552
  G3XBI       +0.4   2771   1.000000399
  G3YPP       +0.1   1141   1.000000150
  G4HSO       -3.0  10593   0.999996957
  G4ZFE       -1.3  10163   0.999998735
  GI4DOH*     +0.0   5620   1.000000035
  HA1VHF      +0.6   8531   1.000000632
  HA8TKS      +0.2   7089   1.000000163
  HB9BXE      +0.4   5957   1.000000405
  HB9CAT      +4.7   2466   1.000004709
  HB9DCO      +0.5   8777   1.000000491
  HB9RB       -7.2    487   0.999992800
  HG0Y        -0.4   1617   0.999999572
  HG5FMV      +0.3    682   1.000000288
  HG8A        -0.4   8841   0.999999583
  HS/F8UKP    +0.1    319   1.000000073
  IK3STG      +4.5   3399   1.000004534
  IK4VET      +0.3  10068   1.000000282
  JA4ZRK      -0.7     62   0.999999318
  JG1DLY      -0.5    250   0.999999515
  JH4UTP      +0.0     97   1.000000000
  JH7CSU1     +4.6    480   1.000004567
  JI1HFJ      -1.8    329   0.999998243
  JJ2VLY      -2.6    139   0.999997410
  JN1ILK      -0.6   2256   0.999999412
  K1TTT       -0.8   4776   0.999999226
  K2PO/7      +0.7   3272   1.000000662
  K3LR        +2.5   5684   1.000002546
  K3PA-1      +0.4   5545   1.000000398
  K4PP        +0.2   4688   1.000000185
  K5TR        +0.9   5315   1.000000927
  K6FOD*      +0.1   3674   1.000000090
  K7EG        +1.7   4629   1.000001662
  K7EK        -0.2   1879   0.999999838
  K7MJG       -8.7   2662   0.999991281
  K9IMM*      -0.0   5378   0.999999964
  K9LC*       -0.0   6136   0.999999976
  KC4YVA      +5.5   3098   1.000005535
  KD2OGR      +0.2   4502   1.000000155
  KH6LC*      -0.1   1754   0.999999863
  KM3T*       -0.0   8739   0.999999987
  KM3T-2      -0.8   8209   0.999999153
  KM3T-3      -0.7   9262   0.999999340
  KV4TT       +0.2   6033   1.000000208
  LZ3CB*      +0.0   4198   1.000000024
  LZ4AE       +3.2   9268   1.000003190
  LZ4UX*      +0.0   7066   1.000000011
  LZ5DI*      +0.0   2075   1.000000033
  LZ7AA       +0.4   8036   1.000000420
  M0WTL       -0.9    265   0.999999140
  MM0ZBH      -0.3   7746   0.999999661
  MM3NDH*     -0.0   6177   0.999999976
  MW0MUT      +1.0   9364   1.000001024
  N4RLI       -1.2   3555   0.999998824
  N4ZR        -1.0    180   0.999998957
  N6TV*       +0.1   1942   1.000000148
  N7TUG       +8.8   2240   1.000008800
  NA0B*       -0.1   1104   0.999999916
  NC7J        +0.7   5741   1.000000720
  ND7K*       -0.1   6736   0.999999867
  NH6HI       +5.3     28   1.000005313
  NN3RP       -0.2   4003   0.999999763
  NR4U        +0.2   3656   1.000000156
  OE9GHV*     +0.0  10934   1.000000025
  OG66X       -1.3    164   0.999998712
  OH4KA       -1.4   5693   0.999998634
  OH6BG       +0.6   6221   1.000000636
  OK1FCJ*     +0.1   7886   1.000000087
  OK1HRA      -4.0   4048   0.999996035
  OK4QRO*     +0.0   6281   1.000000045
  OL9A        +1.9   6060   1.000001910
  ON3URE      +1.9   7618   1.000001872
  ON6ZQ       -0.7   1495   0.999999264
  OZ4ADX      +0.3    708   1.000000282
  PA0MBO      +0.2   2684   1.000000226
  PD2RPS     +14.2   4316   1.000014155
  PJ2A        -0.5   3351   0.999999542
  R6YY*       +0.1   8257   1.000000084
  R9IR*       -0.2    760   0.999999824
  RK3TD*      +0.1   7619   1.000000079
  RN4WA*      -0.1   6856   0.999999899
  RU9CZD      -0.3   4645   0.999999670
  S50C-1      +3.8     58   1.000003762
  S50U        +1.8   1949   1.000001825
  S53A        +0.8  11315   1.000000752
  S53WW       -3.3   9729   0.999996734
  SE5E        +0.3   8954   1.000000294
  SM7IUN      +0.2   8354   1.000000185
  SV8RV       +0.7   4943   1.000000671
  TF3Y        +1.4   7976   1.000001436
  TF4M        -1.6   8162   0.999998400
  TI7W        +2.6   3085   1.000002551
  UA0S        -2.0   6323   0.999998029
  UA3REO      +0.3    123   1.000000348
  UP2L        -4.3   2080   0.999995739
  UY2RA       +2.8   6337   1.000002753
  V51YJ       +2.0   1812   1.000001968
  VE2WU*      -0.1   3232   0.999999888
  VE6AO       -1.5   2453   0.999998524
  VE6JY       +1.8   4807   1.000001762
  VE6WZ       +3.3   4518   1.000003271
  VE7CC       +0.4   4216   1.000000351
  VK2EBN      +0.8    154   1.000000780
  VK2GEL      -0.5    219   0.999999487
  VK3RASA     +1.1    514   1.000001098
  VK6ANC      -1.3   1331   0.999998673
  VR2FUN      +1.3    810   1.000001317
  VR2FUN-74   -0.4    600   0.999999623
  VU2PTT      +0.4    833   1.000000431
  VU3ESV*     +0.0    564   1.000000040
  VY0ERC      -0.5     17   0.999999511
  W1NT-2      +0.4   8318   1.000000353
  W1NT-6      +0.2  11142   1.000000212
  W2LB        +0.8   1310   1.000000803
  W2MV        +0.6   2165   1.000000598
  W2NAF       +0.9   3738   1.000000866
  W3LPL       +1.1   5573   1.000001082
  W3OA        +0.3   6894   1.000000322
  W3RGA       +0.2   7677   1.000000153
  W3UA*       -0.0   1860   0.999999984
  W4AX        +3.7   1020   1.000003704
  W6YX        +0.1   4131   1.000000098
  W7MRF       +5.7   1007   1.000005679
  W8WTS       -2.4   5176   0.999997584
  W8WWV       -2.1   6467   0.999997906
  WA7LNW      +1.3   5039   1.000001336
  WB6BEE*     +0.0   6341   1.000000009
  WC2L        +0.2   6617   1.000000218
  WE9V        -0.3   7834   0.999999654
  WS3W*       +0.5   1909   1.000000495
  WZ7I*       -0.1   8742   0.999999927
  ZF1A        +0.6   3685   1.000000570
  ZL2KS       -0.9    646   0.999999136
  ZL3X        -0.3   2019   0.999999679

Last updated 2023-02-06 00:17:27 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    0205  0204  0203  0202  0201  0131  0130  0129  0128  0127
---------------------------------------------------------------------
2E0EBM                             +0.4                              
3B8CW      +0.0  +0.1  -0.0  -0.1  +0.1  -0.4  -0.3  -0.2  -0.9  -0.4
3D2AG      -0.2  +0.3  +0.3  +0.1  +0.3  +0.3  +0.2  +0.5  -0.3  +0.0
3V8SS            -1.7  -2.4  -2.7  -2.9  -3.0  -3.6  -3.2  -3.5  -2.6
5W1SA      +1.3        +1.5  +1.0  +1.1  +1.1  +0.5  +0.5  +0.8  +0.4
7N4XCV     +2.0  +1.2  +1.1  +0.8  +1.1  +1.1  -0.3  +1.5  +0.8  +0.8
9M2CNC     -0.3  -0.8  -0.3  -0.1  -0.3  -0.2  -0.1  -0.9  -0.1  -0.6
AA4VV      +0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0
AC0C-1     -0.1  +0.0  +0.0  +0.0  -0.0  +0.1  +0.0  +0.1  -0.0  +0.1
BA6KC      +2.6  +1.7  +1.5  +1.6  +1.6  -0.1  +1.6  +1.8  +2.7  +1.7
BD4QJP     +0.8  +0.7  +0.0  +0.0  +1.8        +0.0        +0.9  +0.9
BD7DT      +0.3  -0.2  -0.9  -1.1  +0.2  +0.7  +0.1  +1.2        +0.6
BD7JNA     -0.6  +0.0  +0.0  +0.0  +0.5  +0.0  +0.0  +0.0  +0.7  -0.3
BD8BIN           -2.5                                                
BG4GOV     +0.1  -0.8  +0.0              -0.8  -0.7  -0.5  -0.2  -0.7
BG4GOV3    +4.7  +5.1                                      +4.3  +2.4
BG4WOM     -6.1  -6.5  -5.0  -6.2  -4.5  -5.5  -6.6                  
BG8FZU     -0.9  -0.0  -0.0  +0.0  -0.1  -0.2  -0.5  -0.4  -0.6  -0.5
BH3BBJ     +0.2  -0.2              +0.7  +0.3  +0.3  +0.1  +0.1  -0.2
BH4DEG     +3.3  +2.8  +1.3  +2.0  +1.7  +1.7  +2.1  +3.6  +3.2  +2.0
BH4RRG0    +2.0  +1.8  +1.1  +0.9  +1.8  +0.7  +1.0  +1.4  +1.1  +0.5
BH4RRG     +0.3  +0.1  +0.4  +0.1  -0.6  +0.1  +0.1  +0.3  +0.2  +0.3
BH4XDZ     +0.5  -0.2  +0.4  +0.2  +0.2  +0.0  +0.3  +1.0  +0.5  -0.5
BH4XDZ-1   +1.0  +0.1  +0.4  -0.1  -0.6  +0.5  -0.1  +0.0  +0.6  +0.2
BI4MPH     +8.9                                                  +1.5
BI4RFP-1   +1.3  +0.7  +0.4  +0.6  +1.5  -0.4  +0.3  +0.3  +0.0  -0.5
BU2EQ                                                      +0.4      
CT2IWW                             +0.9  +0.9                    +0.0
CX6VM      -1.8  -1.7  -1.4  -1.0  -0.3  -0.3  -1.0  -1.2  -0.8  -0.5
DC8YZ      +0.0  -0.0  +0.0  +0.1  -0.0  +0.0  +0.1  -0.0  +0.0  -0.0
DD5XX      -0.0  +0.4  +0.1  +0.0  -0.1  -0.4  -0.6  -0.5  -0.5  -0.3
DE1LON     -0.9  -0.9  -0.5  -0.1  -0.2  -0.1  -0.2  -0.2  +0.1  -0.0
DE2SAX     -0.7  -0.8  -0.4  -0.3  -0.3  -0.4  -0.3  -0.3  -0.4  -0.2
DF2CK      -0.1  +0.1  +0.3  +0.1  +0.1  -0.2  -0.3  -0.5  -0.5  -0.4
DF7GB      +0.0  -0.0  +0.0  +0.1  -0.0  -0.0  +0.0  +0.1  -0.0  +0.1
DG6FL     -28.7                                                      
DJ2BC                  -0.7  -0.8  -0.8  -0.8  -1.0  -0.9  -1.1  -0.8
DJ9IE            -0.0  +0.0  +0.0  +0.0              -0.3  -0.6  -3.6
DK0TE     +16.7 +16.7 +16.5 +15.8 +16.4 +16.3  +8.3  +2.3  +1.9  +1.8
DK3UA            -7.7  -8.3  -7.6  -7.5  -7.6  -7.6  -7.7  -7.9  -6.7
DK9IP      -0.2  -0.2  -0.2  -0.2  -0.1  -0.1  -0.1  -0.1  -0.0  -0.1
DL0LA      -0.0  -0.1  -0.0  -0.1  +0.0  -0.1  -0.1  +0.1  -0.1  -0.1
DL0PF      +1.2  +1.5  +2.0  +1.8  +1.5  +1.7  +1.3  +1.2  +1.1  +1.3
DL1AMQ                                               +0.7        +0.4
DL1AXX                 -0.1  -0.5  -0.6                    -0.6      
DL1HWS     +0.3  +0.4  +0.2  +0.1  +0.2  +0.2  +0.2  +0.2  +0.3  +0.2
DL8LAS     +1.2  +1.1  +0.8  +0.9  +1.0  +0.8  +1.0  +1.5        +0.7
DL8TG      -0.1  -0.1  -0.0  -0.1  -0.2  -0.0  -0.2  +0.2  -0.2  +0.0
DL9GTB     -0.7  -0.3  -0.2                                          
DM5GG      +0.3  +0.3  +0.2  +0.2  +0.2  +0.2  +0.2  +0.2  +0.2  +0.2
DM6EE      +0.1  +0.1  +0.0  -0.1  +0.0  +0.0  -0.1  +0.0  -0.0  -0.1
DM7EE                  +0.0  +0.0  +0.0  -1.0                        
DO4DXA     -0.1  -0.3  -0.3  -0.2  -0.1  -0.2        +0.6  -0.4  -0.2
DP6M                               -1.6  -1.6  -1.7  -1.5  -1.7  -1.3
DP7D       +0.0                                      +0.0        +0.3
EA1DAV     -0.8  -0.4  +0.1  +0.7  +0.8  +0.0  -0.8  -0.4  +0.0  -0.7
EA1RX      -6.2  -6.3       -11.8 -15.0 -10.0 -11.5 -10.7 -11.1 -10.6
EA1URA     +0.1  +0.1  +0.3  +0.1  +0.1  +0.0  -0.1  -0.3  -0.3  -0.0
EA2CW      -0.3  +0.0  -0.5  -0.3  -0.1  -0.1  +0.1  -0.0  -0.4  -0.2
EA2RCF-4   +0.0  -0.0  -0.0  +0.0  -0.0  +0.1  +0.0  +0.0  +0.1  -0.0
EA5WU      -0.7  -0.7  -0.4  -0.5  -0.7  -0.8  -0.7  -0.8  -0.7  -0.6
EA8BFK           -0.4  -0.3  -0.4  -0.4  -0.4  -0.3  -0.3  -0.3  -0.3
EA8/DF4UE  -0.5  -0.7                                                
ES2RR      -1.4  -0.9  +0.0  -0.1  +0.0  +0.0  -0.0  +0.0  -0.0  +0.0
EU1ST                  +4.1        +5.1                              
EY8ZE      -1.2  -1.4  -0.8  -0.7  -1.1  -1.3  -1.4                  
F4EGZ/P                                                          -1.5
F4VSQ      +3.8  +3.6  +3.5  +3.4  +3.7  +3.6  +3.6                  
F5AHD                                                -3.1  +2.5      
F6IIT      -1.4  -1.5  -0.9  -1.5  -0.9  -1.3  -1.3  -1.6  -1.6  -1.3
F8DGY      +0.0  -0.1              -4.9  -0.4                    -0.2
G0KTN      +0.3  +0.3  +0.3  +0.2  +0.2  +0.3  +0.3  +0.1  +0.2  +0.1
G0TAI      -0.4  -0.7  -0.4  -0.7  -0.4  -0.5  -0.1                  
G0TMX            +0.4                                                
G3XBI      +0.4  +0.3  +0.2  +0.1  +0.3  +0.2  +0.2  +0.3  +0.3  +0.4
G3YPP      +0.1  +0.0  -0.1  +0.1  +0.1  +0.1  +0.2  +0.1  +0.0  -0.0
G4AON                  +1.0        +1.7  +1.4  +1.2              +0.9
G4HSO      -3.0  -2.8  -2.2  -2.7  -3.3  -2.6  -1.9  -2.4  -3.1  -3.3
G4ZFE      -1.3  -1.2  -0.3  -0.6  -0.6  -0.7  -0.6  -1.0  -1.0  -0.5
GI4DOH     +0.0  +0.0  +0.1  +0.0              -0.3  +0.0  +0.1  +0.0
GM6DX                                                            +0.4
HA1VHF     +0.6  +0.8  +0.7  +0.6  +0.5  +0.4  +0.4  +0.4  +0.7  +0.6
HA5PP                        +0.5                                    
HA8TKS     +0.2  +0.1  +0.2  +0.1  +0.2  +0.2  +0.2  +0.3  +0.1  +0.1
HB9BXE     +0.4  +0.5  +0.4  +0.2  +0.3  +0.3  +0.1  +0.3  +0.2  +0.2
HB9CAT     +4.7  +4.5  +4.4  +3.8  +4.4  +3.2  +3.4  +4.3  +4.0      
HB9DCO     +0.5  +0.3  +0.3  +0.1  +0.2  +0.1  +0.2  +0.3  +0.3  +0.4
HB9RB      -7.2  +0.2                                +0.7  -3.1      
HG0Y       -0.4  -0.2  -0.3  -0.1  -0.0  -0.4  -0.2  -0.3  -0.3  -0.1
HG2EWS                 +1.8                                          
HG5FMV     +0.3  +0.2  -0.1  -0.1  +0.5  +0.1  -0.0                  
HG8A       -0.4  -0.7  +0.0  +0.8  +0.9  +0.8  -0.1  -0.4  -0.6  +0.5
HS/F8UKP   +0.1  -0.2  -0.4  +0.1  -0.0  +0.2  -0.6  -1.1  -0.4  +0.1
IK3STG     +4.5  +4.7  +3.9  +4.2  +2.9  +4.1  +4.7  +5.9  +4.1  +3.8
IK4VET     +0.3  +1.0  +0.6  +0.5  +0.5  +0.1  -0.0  -0.1  -0.2  -0.1
JA4ZRK     -0.7  -0.4  +0.0  +0.0  +0.0  +0.0  +0.0  +0.0  +0.1  -1.5
JG1DLY     -0.5        -0.2                          +0.0            
JH4UTP     +0.0                                                      
JH7CSU1    +4.6  +4.6  +3.4  +4.5  +2.7  +2.8  +3.4  +2.8  +3.5  +2.9
JI1HFJ     -1.8  -3.7  -3.7  -3.4  -4.6  -3.3  -4.0  -3.4  -5.2  -5.2
JJ2VLY     -2.6  -1.9  -1.1  -3.0  -5.3  -2.5  -4.3  -2.3  -2.4  -3.3
JN1ILK     -0.6  -0.4  -0.9  -0.4  -1.5  -1.7  -1.6  +1.5  +0.0  -0.7
K1TTT      -0.8  -1.3  -0.8  -0.6  -0.5  -0.6  -0.4  -0.4  -0.3  -0.5
K2PO/7     +0.7  +0.5  +0.5  +0.4  +0.3  +0.5  +0.3  +0.4  +0.7  +0.9
K3LR       +2.5  +4.4  +4.7  +4.5  +3.4  +4.1  +3.8  +3.7  +4.1  +3.5
K3PA-1     +0.4  +0.7  +0.3  +0.5  +0.2  +0.4  +0.3  +0.3  +0.4  +0.7
K4PP       +0.2  +0.0  +0.1  +0.0  -0.1  -0.1  +0.1  +0.0  +0.0  +0.0
K5TR       +0.9  -0.2              +0.1  +0.2  +0.4  +0.6  +0.4  +0.5
K6FOD      +0.1  +0.1  +0.1  +0.1  -0.0  +0.1  +0.1  +0.0  -0.1  +0.0
K7EG       +1.7  +1.3  +1.0  +1.1  +0.9  +0.7  +0.8  +0.9  +1.2  +0.9
K7EK       -0.2  -0.0  -0.4 -12.8 -11.7 -12.8  -7.1  -7.6  -7.1  -5.3
K7MJG      -8.7  -9.8  -8.5 -11.2  -8.4 -11.1  -9.7 -10.6  -8.7  -9.6
K9IMM      -0.0  -0.1  -0.0  -0.1  -0.0  -0.1  -0.1  -0.1  -0.0  -0.1
K9LC       -0.0  -0.1  -0.0  -0.0  -0.0  -0.0  +0.1  +0.1  +0.3  +0.3
KC4YVA     +5.5  +5.5  +5.3  +4.4  +5.0  +4.9  +5.4  +4.9  +5.4  +4.4
KD2OGR     +0.2  +0.1  +0.1  +0.0  +0.0  -0.0  -0.0  +0.0  +0.1  -0.1
KH6LC      -0.1  -0.1  +0.0  +0.4  +0.1  -0.0  -0.0  +0.1  -0.0  +0.0
KM3T       -0.0  -0.0  +0.0  -0.0  -0.0  +0.1  -0.0  -0.0  -0.0  +0.0
KM3T-2     -0.8  -1.1  -0.4  -0.4  -1.0  -0.6  -0.6  -0.8  -0.9  -0.5
KM3T-3     -0.7  -0.9  -0.3  -0.3  -0.6  -0.6  -0.5  -0.5  -0.8  -0.4
KV4TT      +0.2  +0.1  +0.1  +0.1  +0.1  -0.0  -0.0  -0.1  +0.0  +0.2
LY3G             +0.6                                      +1.0      
LZ3CB      +0.0  +0.0  +0.1  -0.1  -0.0  -0.1  -0.0  +0.1  +0.1  -0.1
LZ4AE      +3.2  +2.9  +2.1                    +1.9  +3.1  +3.0  +2.6
LZ4UX      +0.0  -0.0  -0.0  +0.0  +0.0  +0.0  -0.0  -0.0  -0.0  +0.0
LZ5DI      +0.0  +0.1  -0.1  +0.1  +0.1  +0.2  +0.1  +0.2  +0.2  +0.2
LZ7AA      +0.4  +0.5  +0.4  +0.3  +0.2  +0.3  +0.3  +0.3  +0.4  +0.3
M0WJG                                                +0.6            
M0WTL      -0.9                                                      
MM0ZBH     -0.3  +0.1  +0.2  +0.1  -0.0  -0.2  +0.1  +0.1  +0.1  -0.2
MM3NDH     -0.0  -0.1  -0.0  -0.0  +0.0  -0.1  -0.1  -0.1  +0.0  -0.1
MW0MUT     +1.0  +0.5  +0.7  +0.4  +0.8  +0.7  +0.6  +0.8  +0.4  +0.6
N2QT                                     +0.5  +1.2  +1.3  +1.5  -0.6
N4RLI      -1.2  -1.2  -0.6        -1.0  -0.8        -0.8  -1.0  -0.8
N4ZR       -1.0                                -0.5  -0.7  -0.9  -0.5
N6TV       +0.1  +0.0  +0.1  -0.0  -0.2  -0.1  +0.1  -0.0  +0.0  +0.2
N6WIN-7                                                    -1.2  -0.4
N7TUG      +8.8  +8.9  +9.0  +9.6  +8.7  +8.3  +7.5  +8.5  +8.7  +8.0
N8AI                   +0.0  +0.0  +0.1        +0.5  +0.3  +0.0  +0.0
NA0B       -0.1  -0.2  -0.1  -0.1  +0.2  +0.0  -0.0  +0.1            
NC7J       +0.7  +0.4  +0.2  +0.5  +0.3  +0.4  +0.2  +0.4  +0.3  +0.4
ND7K       -0.1  -0.7  -0.7  -0.6  -0.9  -1.0  -0.7  -0.6  -0.7  -0.7
NH6HI      +5.3  +4.0  +5.6  +5.5  +5.7  +4.7  +4.6  +4.6  +4.0  +4.3
NN3RP      -0.2  -0.4  -0.0  +0.0  +0.1  +0.2  +0.3  +0.1  +0.4  +0.2
NR4U       +0.2        +0.5  +0.3  -0.0  -0.1  -0.2  -0.4  -0.6  -0.5
OE9GHV     +0.0  -0.0  -0.0  -0.1  -0.1  -0.1  -0.0  -0.1  +0.0  -0.1
OG66X      -1.3  -1.0  -0.8  -1.1  -0.8  -1.5  -0.8  -0.9  -0.8  -0.1
OH4KA      -1.4  -1.0  -0.5  -0.3  -0.2  -0.0  +0.4  -0.7  -0.3  -0.1
OH6BG      +0.6  +0.2  -0.6  -0.5  -0.7  -0.5  -0.9  +0.3        +0.7
OH8KA            +1.2  +0.7  +0.6  +0.8  +0.6  +0.7  +0.8        -1.1
OK1FCJ     +0.1  -0.0  -0.0  -0.1  -0.1  -0.2  -0.2  +0.5  +0.6  +0.5
OK1HRA     -4.0  -4.9  -5.3  -5.2  -5.8  -5.5  -5.4  -5.1  -5.4  -5.3
OK4QRO     +0.0  +0.1  +0.2  -0.0  +0.1  +0.1  +0.2  +0.1  +0.0  -0.0
OL9A       +1.9  +1.8  +1.5  +1.5  +2.2  +2.3  +2.1              +1.3
ON3URE     +1.9  +1.8  +1.5  +1.2  +1.2  +1.1  +1.1  +1.3  +1.3  +0.9
ON6ZQ      -0.7  -1.3  -0.6  -0.5  -0.5  -1.3  -0.5  -0.5  -0.6  -0.5
ON7KEC           +0.9  +0.4  +0.3  +0.4  +0.3                        
OZ4ADX     +0.3                          +0.2  +1.0  +0.1  +0.1  +0.0
PA0MBO     +0.2  +0.2  +0.1  +0.1  +0.0  -0.2  +0.2  +0.1  +0.1  +0.2
PA8MM                              -7.1                              
PD2RPS    +14.2 +14.7 +14.1 +14.0 +13.8 +14.0 +14.9 +14.6            
PE1ITR                       -0.4                                    
PJ2A       -0.5  -0.3  -0.2  -0.3  -0.2  -0.2  -0.2  -0.4  -0.2  -0.4
R6YY       +0.1  +0.0  -0.0  -0.0  +0.1  +0.0  -0.0  +0.3  +0.1  -0.4
R9IR       -0.2  -0.4  -0.1  -0.3  -0.2  +0.0  +0.1  +0.1  +0.0  +0.1
RK3TD      +0.1  +0.1  +0.2  +0.1  +0.0  +0.0  +0.2  +0.1  -0.1  +0.0
RN4WA      -0.1  -0.3  -0.3  -0.4  -0.3  -0.3  -0.3  -0.2  -0.2  -0.3
RU9CZD     -0.3  +0.0  +0.2  +0.9  +1.9  +1.6  +0.4  +0.7  +0.6  +1.5
S50ARX                       +2.4        +1.6  +2.1  +2.9  +2.6  +1.7
S50C-1     +3.8                                                      
S50U       +1.8  +1.9  +1.2  +1.3  +1.0  +0.6  +1.2  +1.7  +1.4  +1.1
S53A       +0.8  -0.0  -0.8  -0.8  -0.9  -0.9  -0.8  -0.8  -1.1  -0.8
S53WW      -3.3  -3.2  -2.6  -2.9  -3.2  -3.0  -2.9  -2.9  -3.4  -2.8
SE5E       +0.3  +0.1  -0.9  -0.6  -0.5  -0.4  -0.3  -0.4  -0.6  -0.5
SM7IUN     +0.2  +0.1  -0.0  +0.3  +0.2  +0.1  +0.1  +0.0  -0.1  +0.1
SV8RV      +0.7  +0.7  +0.6  +0.5  +0.5  +0.8  +0.6  +0.6  +0.6  +0.5
TF3Y       +1.4  +1.3  +1.1  +1.1  +1.0  +1.0  +0.8  +1.2  +1.2  +1.1
TF4M       -1.6  -1.7  -1.3  -1.5  -1.4  -1.4  -1.7  -1.3  -1.4  -1.8
TI7W       +2.6  +2.4  +2.7  +2.6  +2.5  +2.5  +2.5  +1.9  +3.0  +2.7
UA0S       -2.0  -2.9  -2.2  -2.4  -2.4  -2.4  -2.9  -1.9  -1.6  -1.7
UA3REO     +0.3  +0.4  +0.1  +0.6  +0.6  +0.3  +0.2  +0.4  +0.7  +0.3
UA4M                   +2.8  +3.9  +4.2  +3.0  +3.5  +4.6  +3.2      
UP2L       -4.3  -4.1  -3.1  -4.0  -2.8  -3.5  -3.4              -3.4
UY2RA      +2.8  +2.5  +1.9  +2.0  +2.0  +2.4  +2.1  +2.5  +2.8  +1.6
V51YJ      +2.0  +1.7  +1.7  +1.7  +1.4  +1.5  +1.1  +1.6  +1.5  +1.5
VE2WU      -0.1  -0.0  +0.7  -0.1  +0.5  +0.6  -0.2  -0.1  -0.1  -0.0
VE3NZ            -1.0  -0.6  -0.7  -0.8  -0.6                    -0.4
VE6AO      -1.5  -1.8  -1.5  -2.2  -2.4  -1.7  -2.0  -2.8  -2.5  -1.0
VE6JY      +1.8  +2.2  +2.0  +1.3  +1.7  +1.7  +1.8  +1.9        +1.2
VE6WZ      +3.3  +2.9  +2.8  +2.3  +2.8  +2.9  +2.5  +1.4  +2.8  +2.5
VE7CC      +0.4  +0.3  +0.2  +0.1  +0.2  +0.1  +0.1  +0.1  +0.2  +0.2
VK2EBN     +0.8                    +0.0                              
VK2GEL     -0.5                                                      
VK3RASA    +1.1  +0.7  +0.6  +0.3  +0.0  +1.2  +0.7  +1.4  +2.7  +1.5
VK6ANC     -1.3  -1.1  -0.9  -1.2  -0.7  -1.0  -0.7  -1.1  -1.5  -0.8
VR2FUN     +1.3  +1.2  +1.5  +1.8  +1.5  +1.7  +1.5  +1.2  +0.9  +0.5
VR2FUN-74  -0.4  -0.6  -0.2  -0.4  +0.1  +0.0  -0.1  -0.9  -0.7  -0.7
VU2PTT     +0.4  +0.6  +0.3  +0.4  +0.3  +0.8  +0.9  +0.2  +0.4  +0.7
VU3ESV     +0.0  +0.2  +0.1  +0.0                    +0.0  -0.6  +0.3
VY0ERC     -0.5  -0.8                          -1.4  +0.0  -0.7      
W1NT-2     +0.4  +1.1  +0.0  +0.0  +0.0  +0.1  +0.1  +0.1  +0.1  +0.0
W1NT-6     +0.2  +1.2  +0.1  +0.1  +0.1  +0.1  +0.1  +0.2  +0.3  +0.3
W2LB       +0.8  +0.2  +0.1  +1.0  +0.7  +0.3  +0.7  +0.4  +0.6  +0.1
W2MV       +0.6  +0.4  +0.5  +0.5  +0.1  +0.3  +0.4  +0.4  +0.0  +0.1
W2NAF      +0.9  +0.1  +0.2  +0.7  +0.7  +0.8  +0.8  +1.1  +1.1  +0.5
W3LPL      +1.1  +0.5  +0.5  +0.6  +0.5  +0.5  +0.5  +0.7  +0.7  +0.5
W3OA       +0.3  +0.3  +0.3  +0.2  +0.3  +0.3  +0.2  +0.2  +0.2  +0.2
W3RGA      +0.2  -0.0  -0.1  +0.1  +0.3  +0.2  +0.2  +0.2  +0.5  +0.4
W3UA       -0.0  -0.0  +0.2        -0.0  -0.1  -0.0                  
W4AX       +3.7  +3.6  +3.3  +2.6  +3.6  +3.4  +2.8  +3.0  +3.2  +2.7
W4KAZ            -4.3  -3.3  -2.6  -2.7  -2.0  -2.1  -3.1  -3.3  -3.2
W6YX       +0.1  +0.4  +0.3  -0.2  -0.2  -0.2  -0.2  -0.3  +0.0  +0.1
W7MRF      +5.7                                                      
W8WTS      -2.4  -2.5  -2.3  -1.9  -2.2  -1.8  -1.8  -1.7  -2.1  -2.0
W8WWV      -2.1  -2.3  -2.1  -1.6  -1.9  -1.8  -1.8  -1.8  -1.9  -1.8
WA7AI                  -0.5  -0.6  -0.8  -0.7  -0.4  -0.2        -0.1
WA7LNW     +1.3  +0.7  +0.3  +0.2  +0.2  +0.3  +0.3  +0.5        +0.5
WB6BEE     +0.0  -0.0  -0.1  -0.0  -0.1  +0.0  +0.0  -0.1  -0.0  +0.0
WC2L       +0.2  -0.3  -0.4  +0.1  +0.1  -0.0  +0.1  +0.0  +0.1  +0.1
WE9V       -0.3  -0.7  -0.6  -0.5  -0.8  -0.6  -0.4  -0.5  -0.6  -0.4
WF7U                                                             -9.4
WS3W       +0.5  +2.0  +1.5  -0.3  +1.3  +2.2  +1.5  +1.8  +1.9  +0.4
WZ7I       -0.1  -0.1  -0.1  -0.1  -0.0  -0.0  -0.1  -0.0  -0.2  -0.0
ZF1A       +0.6  +0.5  +0.3  +0.4  +0.4  +0.4  +0.4  +0.3  +0.3  +0.1
ZL2KS      -0.9  -0.5  -0.5  -0.8  -0.7  -1.6  -1.4  -1.2  -1.8  -1.2
ZL3X       -0.3  -0.6  +0.4  -0.6  -1.1  -0.9  -1.4  -1.4  -2.1  -1.3

Last updated 2023-02-06 00:18:00 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.

AA4VV DF7GB KM3T LZ3CB LZ4UX MM3NDH OE9GHV WB6BEE 

Last updated 2023-02-06 00:18:00 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.