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.

4234209 RBN spots between 2023-05-28 00:00 and 23:59 UTC.
817897 spots (19.3%) were from reference skimmers (*).
Average spot flow was 2940 per minute from 202 active CW skimmers.

1961928 spots from 201 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       +1.0   4211   1.000001005
  3D2AG*      +0.0   1689   1.000000005
  3V8SS       -1.9   5357   0.999998077
  7N4XCV      +1.2   1906   1.000001191
  9M2CNC      -0.3   5373   0.999999745
  AC0C-1      +0.2  18648   1.000000248
  BA6KC       -0.1   5120   0.999999888
  BD4QJP      +4.8      8   1.000004754
  BD7DT       +1.4   9470   1.000001439
  BD7JNA      +6.8   4482   1.000006777
  BD7JNA1     +0.6   5281   1.000000587
  BD7LAE      -5.3   3364   0.999994748
  BD8CS/8*    -0.1  10352   0.999999867
  BG2TEM      -4.9   2299   0.999995052
  BG2TFW      +7.6    873   1.000007567
  BG2UKX      +5.1    112   1.000005052
  BG4GOV3     +1.0   3817   1.000000999
  BG4WOM      +1.0   4196   1.000001004
  BG8FZU      +4.8   3053   1.000004791
  BH3BBJ      +1.6   3037   1.000001564
  BH4DEG      +6.1   4677   1.000006061
  BH4RRG*     -0.1   4671   0.999999935
  BH4RRG0     +0.3   2287   1.000000350
  BH4RXP      +0.5   9055   1.000000521
  BH4XDZ*     +0.0   4764   1.000000037
  BI4RFP      +1.5   5566   1.000001492
  CT7ANO      -4.6  22165   0.999995404
  CX7ACH     +17.4    370   1.000017381
  DC8YZ       +0.1  19122   1.000000109
  DD5XX*      -0.1  11246   0.999999890
  DE1LON      +1.0  20972   1.000000986
  DF2CK       +1.7  30219   1.000001668
  DF7GB*      +0.0  18006   1.000000028
  DK0TE       +1.0  20927   1.000001031
  DK3UA       -8.2   4006   0.999991795
  DK9IP       +0.2  14085   1.000000213
  DK9IP-1     +0.2  16476   1.000000182
  DL0PF       +3.7   8407   1.000003711
  DL1AXX*     +0.1  13482   1.000000063
  DL1HWS      -1.8  21309   0.999998158
  DL8LAS      +1.5  14354   1.000001456
  DL8TG*      +0.0  18719   1.000000008
  DL9GTB      -2.8  23318   0.999997151
  DM5GG       +0.4  19898   1.000000411
  DM6EE*      +0.0   5917   1.000000006
  DM7EE       +0.4  15402   1.000000361
  DR4W        -2.0  20935   0.999998039
  E28AC       +4.8   2348   1.000004829
  EA1RX       -6.1   2943   0.999993945
  EA1URA      -1.8  18808   0.999998153
  EA2CW       +0.8  14259   1.000000830
  EA2RCF-4    +0.4  12705   1.000000374
  EA5WU       -0.6   3013   0.999999398
  ES2RR*      -0.0  21722   0.999999998
  EY8ZE       +0.6   9531   1.000000628
  F AHD       +8.5     26   1.000008545
  F1TRE       +0.5     31   1.000000537
  F6IIT       -0.7  17973   0.999999350
  F8DGY       -4.1  12396   0.999995871
  G0KTN       +0.8  20488   1.000000802
  G3XBI       +0.3   8031   1.000000343
  G3YPP       +0.2   4728   1.000000190
  G4HSO       +0.2  22725   1.000000212
  G4IRN       +0.7  15861   1.000000660
  G4ZFE       +0.5  21076   1.000000501
  GI4DOH*     -0.1   3028   0.999999890
  GM6DX       +0.8   5592   1.000000771
  HA1VHF      +1.2  13186   1.000001243
  HA6PX       +0.8  13111   1.000000768
  HA8TKS      +0.5  18777   1.000000527
  HB9BXE*     +0.1  10931   1.000000105
  HB9DCO*     +0.1  16166   1.000000093
  HB9RB       -2.8    752   0.999997154
  HG0Y        +2.0   2555   1.000002014
  HG5FMV      +0.4    500   1.000000378
  HG8A        +1.9  20935   1.000001934
  HS/F8UKP    -0.2   3773   0.999999844
  IK3STG      +7.2   1123   1.000007184
  IK4VET      +3.8  23026   1.000003772
  IV3DXW      -3.8  17619   0.999996190
  JA4ZRK*     -0.0   5963   0.999999975
  JG1DLY      -0.6    410   0.999999408
  JH4UTP      +0.7   8161   1.000000715
  JH7CSU1     +5.1   7403   1.000005145
  JI1HFJ      -1.4   1748   0.999998586
  JJ2VLY      +2.5   6035   1.000002502
  JN1ILK      +0.8   9880   1.000000808
  K1TTT       -0.4   8085   0.999999575
  K2PO/7      -4.9   4670   0.999995102
  K3PA-1*     +0.1   9471   1.000000071
  K4PP        +0.2   8817   1.000000153
  K5EM        +0.1   3798   1.000000113
  K5TR        +0.8   7572   1.000000760
  K6FOD*      +0.1   3773   1.000000089
  K7EG        +1.4    135   1.000001389
  K7EK        +1.3    173   1.000001301
  K7MJG       +0.5   2384   1.000000529
  K9IMM*      -0.1  13914   0.999999912
  K9LC        +0.3  10379   1.000000320
  KB9AMG      +8.0   5066   1.000007950
  KC4YVA      +5.8   9981   1.000005832
  KD2OGR*     -0.0  10651   0.999999977
  KH6LC       +0.4   3395   1.000000391
  KL7RA       +1.1   4529   1.000001125
  KM3T*       -0.0  14623   0.999999958
  KM3T-2      +1.2  16925   1.000001174
  KM3T-3*     -0.1  16909   0.999999857
  KO7SS       +1.2  12873   1.000001175
  LA6TPA      -1.5  10076   0.999998476
  LY2XW       +0.6   1661   1.000000612
  LZ3CB*      -0.0   9635   0.999999981
  LZ4AE       +3.3  25765   1.000003345
  LZ4UX*      -0.1  13275   0.999999891
  LZ5DI*      -0.0  18347   0.999999982
  LZ7AA       +0.9  16684   1.000000852
  M0JYE       -5.8   1896   0.999994192
  MM0ZBH      +1.0  15801   1.000001037
  MM3NDH*     +0.0  22941   1.000000008
  N2QT        +2.7  13485   1.000002739
  N4ZR        +0.3    221   1.000000333
  N6TV        +0.6   6269   1.000000594
  N7TUG      +11.2   2530   1.000011202
  N9CO*       +0.1  14568   1.000000127
  ND7K        +0.4   2348   1.000000446
  NG7M*       +0.0   7283   1.000000042
  NN3RP       +0.4   3865   1.000000401
  NR4U        -0.7    328   0.999999262
  NU6XB*      +0.0   4663   1.000000030
  NX5M        +1.3    631   1.000001294
  OE9GHV*     -0.0  22577   0.999999963
  OG73X       +1.1   6258   1.000001130
  OH6BG       +2.8  22977   1.000002755
  OH8KA       +1.2   7944   1.000001205
  OK1FCJ      +0.3  20442   1.000000284
  OK4QRO      +2.3  19902   1.000002251
  ON6ZQ       -0.7   2145   0.999999343
  OZ4ADX      +7.7   3496   1.000007677
  PA0MBO      +0.7   7139   1.000000698
  PA2SQ       +0.0      9   1.000000000
  PA5KT       -0.8   6193   0.999999176
  PJ2A*       +0.1   7428   1.000000095
  PY7ZC       -2.6   3268   0.999997395
  R6YY        +0.2  18405   1.000000162
  RK3TD       -0.2  19141   0.999999770
  RN4WA       -8.8  16024   0.999991178
  RU9CZD      +4.4  16916   1.000004372
  S50ARX      +3.6  21299   1.000003602
  S53A        +0.9  26481   1.000000929
  S53M        +0.6   5538   1.000000578
  S53WW       +0.3  12222   1.000000297
  SE5E        +0.4  12612   1.000000368
  SM0TCZ      -1.3   3891   0.999998712
  SM7IUN*     +0.1  19389   1.000000073
  SQ5J        +2.7  17130   1.000002729
  SV8RV       -0.3  15161   0.999999676
  SZ1A        -8.5    369   0.999991498
  TF3Y        +1.6  16696   1.000001615
  TF4M        -1.4  16357   0.999998641
  TI7W        +4.7  12041   1.000004730
  TZ4AM       -2.4   1420   0.999997639
  UA0S        -0.1  15033   0.999999926
  UA4M        +5.1   1192   1.000005052
  V51YJ       +1.6   2570   1.000001613
  VE2WU*      +0.0   8423   1.000000007
  VE6AO       -0.6   3472   0.999999396
  VE6JY       +2.1   8917   1.000002142
  VE6WZ       +2.3   8146   1.000002325
  VE7CC       +0.6   4539   1.000000630
  VK2GEL      +1.8   1688   1.000001802
  VK2RH       -0.6   1561   0.999999380
  VK3RASA     -0.7   2106   0.999999267
  VK6ANC      -2.6   3563   0.999997402
  VR2FUN      +3.6   8853   1.000003588
  VR2FUN-74   +0.8   3923   1.000000849
  VU2CPL      +1.7  10222   1.000001723
  VU2PTT      +1.2   3468   1.000001188
  VY0ERC      +1.3     62   1.000001343
  W1NT-2      +0.5  18826   1.000000467
  W1NT-6      +0.4  21289   1.000000391
  W2LB        +6.5    240   1.000006459
  W2MV        +0.5   2940   1.000000518
  W2NAF       +1.6  18265   1.000001645
  W3LPL       -3.1  19669   0.999996881
  W3OA        +0.3  16793   1.000000348
  W3RGA       +0.2  17779   1.000000155
  W3UA*       -0.0  21717   0.999999957
  W4AX        +3.7   4174   1.000003748
  W4KAZ       -1.3  11672   0.999998679
  W6BB*       +0.1   3729   1.000000055
  W6YX        +0.6    219   1.000000618
  W8WTS       -1.9  11602   0.999998112
  W8WWV       -2.0  15944   0.999998032
  WA7LNW      +0.6   9208   1.000000639
  WB6BEE*     -0.1  10665   0.999999925
  WC2L        +0.7  15464   1.000000710
  WE9V        +0.1  14417   1.000000114
  WZ7I*       +0.0  18386   1.000000042
  YU1EW       +0.7   4161   1.000000669
  ZL2KS       -2.6   3740   0.999997380
  ZL3X        -2.9   7031   0.999997112
  ZL4YL       +1.2   2653   1.000001230

Last updated 2023-05-29 00:26:11 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    0528  0527  0526  0525  0524  0523  0522  0521  0520  0519
---------------------------------------------------------------------
3B8CW      +1.0  +1.0  +1.0  +0.6  +1.2  +0.6  +1.6  +0.8  +1.0  +0.5
3D2AG      +0.0  -0.1  +0.0  -0.1  +0.0  +0.0  +0.0  -0.3  -0.1  +0.0
3V8SS      -1.9  -2.0  -2.1  -1.8  -1.7  -1.1  -1.1  -2.0  -1.8  -2.0
4X6FB                                                +0.4            
5B/HA5PP               +1.7  +1.2                                    
7N4XCV     +1.2  +1.5  +0.1                                          
9M2CNC     -0.3  -0.0  -0.2  -0.2        +0.0  +0.1  +0.2  +0.5  +0.1
AC0C-1     +0.2  +0.3  +0.2  +0.2  +0.3  +0.2  +0.2  +0.1  +0.2  +0.0
BA6KC      -0.1  -0.0  +0.0  -0.1  -0.0  -0.3 -21.8  +1.1  -2.4  +0.2
BA6KC1                                         -0.1  -0.9  +1.4  +0.9
BD0AH                                                +0.4  +0.4  +1.0
BD4QJP     +4.8                                +1.5  +3.7            
BD7DT      +1.4  +2.0  +1.0  +0.7  -1.0  -1.6  -2.8  +0.4  -0.3  +0.2
BD7JNA1    +0.6  +0.4  +0.6                                          
BD7JNA     +6.8  +6.7  +3.7  -6.9  -1.2  +0.6  +0.2                  
BD7LAE     -5.3  -5.3  -6.5  -6.8                                    
BD8CS                  -0.2  -0.2  -0.0  +0.1  -0.1  +0.0  +0.1  -0.0
BD8CS/8    -0.1  -0.1  -0.0                                          
BG2TEM     -4.9  -5.0  -5.8  -7.0                                    
BG2TFW     +7.6  +7.4  +6.8  +5.5  +5.8  +5.8  +6.8                  
BG2UKX     +5.1  +8.6                                                
BG4GOV3    +1.0  +1.1  +0.2  -0.2  +0.2  -0.8  -2.9  +3.0  -1.6  +0.7
BG4WOM     +1.0        +0.2  -0.0  -0.4  +0.0  -0.0  +0.6  +0.7  +0.4
BG8FZU     +4.8  +4.3  +4.9  +3.5  +3.9  +5.1        +3.7  +5.2  +4.6
BH3BBJ     +1.6  +1.3  +1.5                                          
BH4DEG     +6.1  +5.8  +5.3  +5.8  +4.4  +5.0  +4.1  +5.2  +5.3  +5.0
BH4RRG0    +0.3  +0.5  +0.3  +0.2  +0.2  +0.3  +0.1  +0.7  +0.8  +0.3
BH4RRG     -0.1  +0.1  -0.1  -0.2  +0.0  -0.0  +0.0  -0.3  +0.2  -0.1
BH4RXP     +0.5  +0.6  +0.3  +0.2  +0.3  +0.4  +0.3  +0.4  +0.8  +0.2
BH4XDZ     +0.0  +0.1  +0.4  -0.0  +0.1  -0.2  +0.0  -0.1  +0.7  +0.9
BH4XDZ-1               -0.1  +0.2  +0.3  +0.1  -0.3  +0.8  +0.6  +0.2
BI4RFP     +1.5  +1.4  +1.1  +1.7  +0.9  +0.9  +0.5  +1.5  +1.7  +0.4
CT7ANO     -4.6  -4.5  -4.9                                          
CX6VM                  -3.8  -3.3  -3.6  -4.7  -4.7  -5.1  -4.4  -3.3
CX7ACH    +17.4 +17.5                                                
DC8YZ      +0.1  -0.1  +0.1  +0.1  +0.1  +0.1  +0.0  +0.0  +0.1  +0.1
DD5XX      -0.1  -0.3  +0.1  -0.3  -0.2  -0.0  +0.2  +0.0  +0.1  -0.3
DE1LON     +1.0  +0.8  +0.6  +0.3  +0.3  +0.5  +0.7  +0.4  +0.5  +0.3
DF1DN                        -6.3  -6.5  -5.9  -8.0  -4.5  -9.0  -6.0
DF2CK      +1.7  +1.7  +1.2  +0.9  +1.0  +1.1  +1.2  +1.2  +1.3  +0.8
DF7GB      +0.0  -0.0  -0.1  +0.0  -0.0  -0.0  -0.1  -0.1  -0.0  -0.1
DG8NCY                 +0.0                                          
DJ2BC                                          -0.3  -0.5  -0.5  -0.4
DK0TE      +1.0  +1.0  +0.7  +0.6  +0.5  +0.6  +0.8  +0.7  +0.8  +0.5
DK3UA      -8.2  -7.9                                                
DK8NE                  -2.0                                          
DK9IP      +0.2  +0.2  +0.2  +0.1  +0.1  +0.1  +0.3  +0.1  +0.1  +0.1
DK9IP-1    +0.2  +0.2  +0.2  +0.0  +0.0  +0.1  +0.2  +0.1  +0.1  +0.0
DL0PF      +3.7  +3.0  +3.9  +4.4  +4.4  +4.8  +5.2  +3.5  +3.3  +3.0
DL1AXX     +0.1  +0.2                                                
DL1HWS     -1.8  -1.5  -1.2  +0.3  +0.3  +0.3  +0.4  +0.3  +0.4  +0.2
DL8LAS     +1.5  +1.3  +0.9  +0.8  +0.8  +0.9  +1.1  +1.0  +1.1  +0.8
DL8TG      +0.0  +0.1  -0.0  +0.0  -0.0  -0.0  +0.0  -0.0  +0.0  -0.1
DL9GTB     -2.8  -3.0  -0.5  -0.0  +0.3  +0.2                        
DM5GG      +0.4  +0.4  +0.3  +0.2  +0.2  +0.3  +0.7  +0.6  +0.8  +0.5
DM6EE      +0.0  +0.1  +0.0  +0.0  -0.0  +0.1  -0.1  +0.0  +0.1  +0.0
DM7EE      +0.4  +0.4  +0.2                                          
DO4DXA                             -0.4  -0.2  -0.2  -0.2  -0.2  -0.2
DR4W       -2.0  -2.5  -2.4  -2.7  -2.6  -1.3  -0.6  -1.6  -2.1  -3.1
E28AC      +4.8  +4.5  +5.0  +5.6  +4.8  +4.6  +4.9  +3.7            
EA1RX      -6.1  -7.8  -7.8  -8.5  -8.3  -7.2  -6.9  -6.9  -7.2  -7.5
EA1URA     -1.8  -1.5  -0.6  -0.2  -0.0  -0.1  +0.2  +0.2  +0.1  +0.3
EA2CW      +0.8  +0.6  +0.2  +0.1  +0.1  +0.2  +0.1  +0.1  -0.1  -0.0
EA2RCF-4   +0.4  +0.2  +0.1  -0.1  -0.0  -0.0  -0.0  -0.1  +0.1  -0.0
EA5WU      -0.6  -0.5  -1.1  -0.3  +0.0  +0.2  +0.1  +0.1  +0.3  +0.2
ES2RR      -0.0  +0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0  -0.0
ET3AA           +10.1                                                
EY8ZE      +0.6  +0.6  +0.4  +0.4  +0.6  +0.4  +0.7  +0.5  +0.4  +0.4
F1TRE      +0.5                                                      
F4VSQ                              +4.5                    +4.3  +4.2
F4VVG                                                +0.0  +0.1  +0.2
F6IIT      -0.7  -0.8  -0.8  -0.9  -1.0  -0.6  -0.5  -1.2  -1.1  -1.5
F8DGY      -4.1  -4.4  -4.5  -4.5  -4.9  -4.5  -4.2  -4.7  -4.9  -5.4
F           AHD   AHD                                                
G0KTN      +0.8  +0.7  +0.6  +0.3  +0.5  +0.4  +0.5  +0.5  +0.6  +0.4
G0TMX            +0.2                                                
G3XBI      +0.3  +0.3  +0.3  +0.0  +0.2  +0.3  +0.5  +0.0            
G3YPP      +0.2  +0.2  +0.2  +0.2  -0.1  +0.1  +0.2  +0.1  +0.1  +0.0
G4AON                                                            +0.6
G4HSO      +0.2  +0.0  +0.1  -0.3  -0.3  -0.1  -0.0  -0.5  -0.2  -0.2
G4IRN      +0.7  +0.8  +0.4  +0.4  +0.4  +0.5  +0.6        +0.6  +0.5
G4ZFE      +0.5  +0.5  +0.4  +0.3  +0.3  +0.3  +0.3  +0.1  +0.4  +0.3
GI4DOH     -0.1  +0.1  +0.1  -0.0  -0.1  +0.0  -0.2  -0.0  +0.0  +0.2
GM6DX      +0.8  +0.7  +0.6  +0.7  +0.4  +0.7  +0.6  +0.7  +0.9  +0.5
HA1VHF     +1.2  +3.8  +0.8  +0.6  +0.5  +0.4  +0.4  +0.1  -0.0  -0.3
HA6PX      +0.8  +3.2  +5.0  +4.1  +4.6  +5.1  +3.4  +4.5  +3.8  +1.5
HA8TKS     +0.5  +0.5  +0.2  +0.3  +0.3  +0.3  +0.3  +0.3  +0.4  +0.2
HB9BXE     +0.1  +0.0  +0.0  -0.1  -0.1  -0.0  +0.0  -0.1  -0.0  +0.0
HB9DCO     +0.1  +0.2  +0.1  -0.0  -0.1  +0.2  -0.2  +0.1  -0.0  +0.1
HB9RB      -2.8  +0.5                                +0.8            
HG0Y       +2.0  +2.2  +1.4                                          
HG5FMV     +0.4  +0.2  +0.2  +0.6  +0.2              +0.3  +0.3      
HG8A       +1.9  +2.1  +1.7  +1.3  +1.4  +1.0  +1.3  +0.8  +0.9  +0.5
HS/F8UKP   -0.2  +0.0  +0.1  +0.5  -0.2  -0.1  -0.4  +0.0  -0.0  +0.2
IK3STG     +7.2  +7.3  +6.5  +7.2  +7.0  +7.2  +7.2  +6.5  +6.7  +6.9
IK4VET     +3.8                    +3.8  +3.2  +2.8  +1.8  +1.5  +1.5
IV3DXW     -3.8  -2.0                                                
JA4ZRK     -0.0  +0.2  -0.1  +0.0  +0.0  +0.0  +0.3  -0.1  -0.1  +0.0
JG1DLY     -0.6                                      -0.8            
JH4UTP     +0.7  +0.8  +0.3  +0.3  +0.0  +0.3  +0.6  +0.8            
JH7CSU1    +5.1  +5.2  +4.4  +5.1  +4.9  +5.5  +5.5  +4.9  +4.9  +4.0
JI1HFJ     -1.4  -1.9  -3.0  +1.3  -4.2  -2.2  -3.8  -2.8  -3.1  -6.0
JJ2VLY     +2.5  +2.5  +1.0  +1.0  +0.6  +0.7  +0.5  +3.0  +1.5  +1.0
JN1ILK     +0.8  +0.7  -0.0  +0.1  +0.7  -0.5  +0.3  +0.9  +0.6  +0.2
K1TTT      -0.4  -0.4  -0.4  -0.3  -0.1  -0.3  -0.5  -0.2  +0.0  -0.2
K2PO/7     -4.9  -4.4  -4.9  -5.9  -4.4  -6.8  -5.0  -6.5  -4.8  -4.8
K3PA-1     +0.1  +0.2  +0.1  +0.1  +0.1  -0.1  +0.0  -0.0  +0.0  +0.1
K4PP       +0.2  +0.2  +0.0  -0.1  -0.1  -0.0  -0.1  -0.0  -0.2  -0.0
K5EM       +0.1  +0.2                                                
K5TR       +0.8  +0.7  +0.4  +1.1  +0.3  +0.6  +0.4  +0.7  +0.5  +0.5
K6FOD      +0.1  +0.1  +0.0  +0.1  +0.2  +0.2  +0.0  +0.3  +0.1  +0.1
K7EG       +1.4  +1.9        +0.9  +0.0                              
K7EK       +1.3  +1.1  -0.5  -1.6  -0.4  -1.1  -1.3  -2.9  -0.5  +0.1
K7MJG      +0.5  +0.7  +0.2  +0.4  +0.4  +0.2  +0.5  +0.6  +0.1  +0.3
K9IMM      -0.1  -0.1  -0.1  -0.1  -0.0  -0.1  -0.1  -0.1  -0.2  -0.1
K9LC       +0.3  +0.3  +0.3  +0.3  +0.4  +0.2  +0.1  +0.1  +0.3  +0.2
KB9AMG     +8.0  +6.8                                                
KC4YVA     +5.8  +5.7  +5.3  +5.5  +5.0  +4.1  +5.1  +5.5  +5.3  +5.6
KD2OGR     -0.0  +0.1  +0.1  +0.0  +0.1  +0.1  -0.0  +0.2  +0.4  +0.1
KH6LC      +0.4  +0.2  +0.2  +0.1  +0.2  +0.4  +0.1  +0.0  -0.2  +0.1
KL7RA      +1.1  +1.1  +0.1  +1.8  +1.8  +3.0  +3.0  +2.8            
KM3T       -0.0  +0.0  -0.1  -0.1  -0.1  +0.0  +0.0  -0.0  +0.0  +0.0
KM3T-2     +1.2  +1.1  +0.7  +0.8  +0.8  +0.6  +0.7  +0.8  +0.9  +0.7
KM3T-3     -0.1  -0.1  -0.1  -0.1  -0.1  -0.1  -0.1  +0.0  -0.1  -0.0
KO7SS      +1.2  +1.2  +1.0  +1.1  +1.1  +0.9  +1.0  +1.0  +1.0  +0.6
LA6TPA     -1.5  -1.7  -0.8  -0.1  +0.1  +0.7  +1.0  +0.5  +0.5  -0.1
LY2XW      +0.6  +0.6                                +0.6            
LY3G                   +0.5  +0.3                                    
LZ3CB      -0.0  +0.1  +0.1  +0.0  -0.0  -0.0  +0.1  +0.0  -0.1  -0.1
LZ4AE      +3.3  +3.4  +3.2  +2.9  +3.1  +2.9  +2.4  +3.1  +2.8  +2.7
LZ4UX      -0.1  -0.1  +0.1  +0.2  +0.1  -0.0  -0.0  +0.0  +0.0  +0.0
LZ5DI      -0.0  -0.0  -0.2  -0.3  -0.0  +0.0  +0.0  -0.1  -0.1  +0.0
LZ7AA      +0.9  +0.8  +0.7  +0.6  +0.6  +0.6  +0.5  +0.7  +0.7  +0.5
M0JYE      -5.8  -8.5 -10.9 -10.6 -10.0             -10.5            
MM0ZBH     +1.0  +1.4  +1.2  +1.1  +1.1  +0.8  +1.0  +0.9  +1.2  +1.0
MM3NDH     +0.0  +0.0  -0.0  -0.0  -0.0  +0.0  +0.1  -0.1  -0.0  +0.0
N2QT       +2.7  +2.8  +2.0                                          
N4ZR       +0.3  -0.0  +0.0  +0.1  -0.0  -0.1  -0.0                  
N6TV       +0.6  +0.6  +0.3  +0.3  +0.5  +0.4  +0.2  +0.8  +0.5  +0.3
N7TUG     +11.2 +11.3 +11.4 +11.5 +12.4 +11.8 +11.0 +11.2 +11.1 +12.4
N9CO       +0.1  +0.0  -0.1  +0.0  +0.1  +0.2  +0.1  -0.1  -0.1  +0.1
NA0B             -0.2  -1.6        +0.0                          +0.0
ND7K       +0.4  +0.4                                +0.3            
NG7M       +0.0  +0.1  +0.0  +0.1  +0.2  +0.1  -0.0  +0.3  +0.0  +0.1
NH6HI                                                      +5.3      
NN3RP      +0.4  +0.4  +0.1  +0.2  +0.1  +0.3  +0.1  +0.1  +0.0  +0.1
NR4U       -0.7  -2.8  +0.0  -0.5  -1.5  -0.1  -0.6  -0.3  -0.5  -0.4
NT6Q                   +0.9  +0.9  +1.1  +1.1  +1.1  +1.8  +1.3  +1.1
NU6XB      +0.0  +0.0  +0.1  +0.1  -0.0  +0.0  +0.0  -0.1  -0.2  +0.1
NX5M       +1.3  +0.9                                                
OE9GHV     -0.0  -0.0  +0.0  -0.1  -0.1  -0.0  -0.0  -0.1  -0.0  -0.0
OG66X            -0.3  -0.3              -0.2  -0.5        +0.0      
OG73X      +1.1  +1.3  +0.4                                          
OH6BG      +2.8  +3.6  +4.4  +4.2  +3.8  +4.5  +3.3  +3.6  +3.0  +3.9
OH8KA      +1.2  +1.3  +0.9  +0.7  +0.4  -1.0  -1.6  -1.9  +1.0  +0.9
OK1FCJ     +0.3  +0.3  +0.2  +0.2  +0.2  +0.2  +0.1  +0.1  +0.1  +0.1
OK4QRO     +2.3  +2.4  +1.5  +1.2  +1.3  +1.3  +1.5  +1.5  +1.6  +1.0
ON6ZQ      -0.7  -1.2  -0.7  -0.7  -0.8  -0.6  -0.6  -0.9  -0.9  -1.1
OZ4ADX     +7.7  +7.9  +8.7  +5.6  +5.1  +4.8  +5.3  +5.4  +4.8  +3.5
PA0MBO     +0.7  +0.6  +0.2  +0.1  +0.4  +0.2  +0.8  +0.5  +0.4  +0.3
PA2SQ      +0.0                                                      
PA5KT      -0.8  -1.0        -1.2                    -0.7  -0.7      
PA5WT                  -2.2                                          
PA8MM                  -5.9  -5.8  -6.1        -5.2              -6.1
PC5Q                   +3.1  -0.3                          +0.5      
PE5TT                                                      +1.3  +0.7
PJ2A       +0.1  -0.1  +0.3  +0.1  +0.1  +0.2  -0.0  -0.1  +0.1  +0.0
PY7ZC      -2.6              -1.9  -1.0  -0.2  -1.5  -2.1  -3.8  -4.1
R6YY       +0.2  +0.2  -0.1  -0.0  -0.1  -0.7  -0.6  -0.5  -0.4  -0.2
RK3TD      -0.2  -0.2  -0.2  -0.1  -0.2  -0.1  -0.4  -0.2  -0.4  -0.3
RN4WA      -8.8  -8.9  -9.1  -9.0  -9.1  -9.0  -9.2  -9.1  -9.5  -9.5
RU9CZD     +4.4  +4.2  +3.0  +3.5  +3.6  +2.7  +2.2  +3.4  +2.3  +1.4
S50ARX     +3.6  +3.5  +3.0  +2.5                                +1.8
S53A       +0.9  +0.9  +0.5  +0.6  +0.6  +0.5  +0.7  +0.6  +0.6  +0.3
S53M       +0.6  +0.5  -0.2                                          
S53WW      +0.3  +0.5  +0.4  +0.3  +0.2  +0.3  +0.4  -0.0  +0.0  -0.2
SE5E       +0.4  +0.4  +0.3  +0.1  +0.1  +0.1  +0.2  +0.2  +0.3  +0.2
SM0TCZ     -1.3  -1.1  +0.3                                          
SM7IUN     +0.1  +0.0  +0.1  -0.2  -0.0  +0.0  +0.1  -0.1  +0.0  -0.0
SP6FCS                                         +0.1  +0.0            
SQ5J       +2.7  +2.7  +2.5  +0.0  -3.5                          -0.8
SV1CDN                 +8.2  +8.0  +3.8  +4.2        +3.6  +3.6  +4.4
SV1DPJ                                                           +0.8
SV8RV      -0.3  +0.2  +0.1  +0.2  +0.2  +0.3  +0.5  +0.4  +0.4  +0.2
SZ1A       -8.5        -5.4  +0.0  -0.3  -2.7  +2.0  +3.2  +5.2      
TF3Y       +1.6  +1.7  +1.1  +1.1  +1.2  +1.2  +1.2  +1.3  +1.5  +1.1
TF4M       -1.4  -1.3  -1.1  -1.1  -1.4  -1.2  -1.0                  
TI7W       +4.7  +4.6  +5.1  +5.1  +5.1  +4.8  +4.8  +4.9  +4.6  +5.2
TZ4AM      -2.4  -2.0  -3.5        -1.5              -2.7  -4.4      
UA0S       -0.1  -0.1  -1.4  -0.5  +0.8  -0.1  -0.3  -0.3  -1.3  -0.5
UA4M       +5.1  +5.1                                      +3.6  +4.7
UP2L                         -4.5  -4.2  -4.5  -3.9  -4.3  -3.9  -4.8
UY2RA                  +2.5  +4.2  +3.6  +2.3  +2.2  +2.5  +2.5  +2.3
V51YJ      +1.6  +1.7  +1.5  +2.1  +0.7  +1.3  +1.4  +1.5  +1.6  +1.1
VE2WU      +0.0  +0.0  +0.1  +0.0  -0.0  -0.0  -0.1  -0.1  +0.0  -0.0
VE6AO      -0.6  -0.5  -0.6  +0.2  -0.3  -0.8  -0.3  -0.5  +0.0  -0.5
VE6JY      +2.1  +2.4  +1.2  +1.0  +1.2  +1.5  +1.0  +1.3  +0.7  +1.2
VE6WZ      +2.3  +2.8  +1.6  +1.9  +2.8  +2.2  +3.0  +2.2  +2.6  +2.7
VE7CC      +0.6  +0.6  +0.3  +0.6  +0.6  +0.2  +0.4  +0.5  +0.8  +0.3
VK2GEL     +1.8  +1.8  +1.0  +0.8  +0.8  +1.0  +0.6  +2.7  +2.4  +0.8
VK2RH      -0.6  -0.2  +0.0  +0.0  +0.0  +0.0  +0.0  -0.1  -0.6  +0.0
VK3RASA    -0.7  -0.5  -0.7  -0.6  -0.1  -0.2  +0.0  -0.3  -0.9  -0.5
VK6ANC     -2.6  -2.2  -4.4  -2.9  -1.2  -1.1  -1.8  -1.5  -2.6  -1.8
VR2FUN     +3.6  +3.5  +3.5  +3.5        +3.1  +3.2  +3.9  +3.3      
VR2FUN-74  +0.8  +0.7  +0.6  +0.4  +0.1  +0.3  +0.3  +1.5  +1.1      
VR2FUN-77       +16.1                               +18.2 +18.1 +17.6
VU2CPL     +1.7  +1.7  +1.4  +1.0  +0.6  +1.2  +0.0  +0.8  +1.9  +2.3
VU2PTT     +1.2  +1.1  +0.4  +0.1  -0.0  +0.6  +0.2  +0.8  +1.1  +0.5
VY0ERC     +1.3  +1.3  +0.0                          +0.0            
W1NT-2     +0.5  +0.4  +0.3  +0.4  +0.4  +0.4  +0.3  +0.5  +0.6  +0.4
W1NT-6     +0.4  +0.2  +0.2  +0.3  +0.3  +0.4  +0.2  +0.3  +0.4  +0.2
W2LB       +6.5        +3.0  +2.3  +1.6  +2.0  +1.4  +1.5  +1.8  +0.5
W2MV       +0.5  +0.4  +0.2  +0.4  -0.0  +0.4  +0.4  +0.4  +0.2  -0.2
W2NAF      +1.6  +1.8  +1.0  +1.2  +1.2  +0.8  +1.0  +1.3  +1.3  +1.2
W3LPL      -3.1  -3.0  -2.9  -2.6  -2.8  -2.5  -3.4                  
W3OA       +0.3  +0.4  +0.3  +0.4  +0.2  +0.4  +0.4  +0.3  +0.4  +0.3
W3RGA      +0.2  +0.1  +0.0  -0.1  -0.0  +0.0  +0.0  +0.3  +0.4  -0.1
W3UA       -0.0  -0.0  -0.1  -0.0  -0.0  -0.0  -0.0  +0.0  -0.0  -0.0
W4AX       +3.7  +4.0  +3.5  +3.1  +3.4  +3.0  +3.2  +3.0  +4.0  +3.4
W4KAZ      -1.3  -1.2  -0.8  -0.6  -0.7  -0.4  -0.5  -0.6  -0.8  -0.8
W6BB       +0.1  +0.0  -0.0  -0.0  -0.2  -0.1  -0.1  +0.3  +0.1  +0.2
W6YX       +0.6  +0.4  +0.0  +0.0  +0.0  +1.1        +0.0            
W8WTS      -1.9  -1.8  -1.4  -1.0  -1.4  -1.1  -1.4  -1.2  -1.6  -1.7
W8WWV      -2.0  -2.0  -1.8  -1.4  -1.3  -1.2  -1.5  -1.3  -1.7  -1.7
WA7LNW     +0.6  +0.5  +0.4  +0.4  +0.4  +0.5  +0.4  +0.5  +0.6  +0.3
WB6BEE     -0.1  -0.0  -0.0  -0.0  -0.1  +0.1  -0.1  -0.2  -0.1  +0.1
WC2L       +0.7  +0.3  +0.1  +0.2  +0.2  +0.1  +0.2  +0.5  +0.3  +0.2
WE9V       +0.1  -0.1  +0.5  +0.6  +0.3  +0.3  +0.3  +1.3  +1.3  -0.0
WS3W             +1.0  +0.8  -0.1  +1.6  +0.2  -1.0  -1.9  +0.7  +1.9
WZ7I       +0.0  +0.1  +0.1  +0.1  +0.1  +0.2  +0.1  +0.1  +0.0  +0.0
YU1EW      +0.7  +0.6  +0.6                                          
ZF1A                   +0.3                                          
ZL2KS      -2.6  -2.6  -2.3  -3.4  -3.6  -2.0  -2.8  -3.1  -3.1  -3.4
ZL3X       -2.9  -2.1  -1.7  -2.6  -5.3  -2.1  -3.6  -2.8  -3.3  -3.7
ZL4YL      +1.2  +1.0  +0.8  +1.6  +1.6  +1.0  +2.2  +2.0            

Last updated 2023-05-29 00:27:33 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 2023-05-29 00:27:33 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.