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.

if you want to implement an automated calibration of your skimmer you can access the skew data in machine-readable CSV format here https://sm7iun.se/rbnskew.csv

491349 RBN spots between 2024-04-24 00:00 and 23:59 UTC.
163251 spots (33.2%) were from reference skimmers (*).
Average spot flow was 341 per minute from 185 active CW skimmers.

262642 spots from 184 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 
  -------------------------------------
  2E0INH*     -0.0   3612   0.999999991
  3B8CW       -1.9    379   0.999998098
  3D2AG       +0.4     49   1.000000364
  3V8SS       -1.2    626   0.999998783
  7N4XCV      -0.0    187   0.999999981
  9M2CNC      +0.2    176   1.000000242
  AA0O*       +0.2   1510   1.000000154
  AA4VV*      -0.1   1974   0.999999929
  AC0C-1*     +0.1   2634   1.000000087
  BA6KC*      +0.1    439   1.000000071
  BD4QJP      +3.1    121   1.000003077
  BD7JNA      -0.0    229   0.999999977
  BD8CS*      +0.1    692   1.000000056
  BG0AJO      +0.2     58   1.000000164
  BG4GOV      +0.1    106   1.000000067
  BG4WOM*     +0.1    360   1.000000062
  BH4RRG      -0.1    209   0.999999940
  BH4RXP      -0.2    508   0.999999805
  BH4XDZ      -0.0    210   0.999999961
  BI4MPH-1    +0.1    124   1.000000144
  BI4RFP-YZ   +0.0    230   1.000000024
  BI4SSB      +0.1    198   1.000000068
  CR6K        -5.0    216   0.999994997
  CX6VM       -3.6    290   0.999996399
  DC8YZ*      +0.1   3187   1.000000115
  DD5XX       -1.3   2088   0.999998708
  DE1LON      -0.2   2481   0.999999762
  DF2CK       -0.3   5028   0.999999688
  DF7GB*      +0.1   2435   1.000000060
  DJ2BC       -0.4   2325   0.999999641
  DJ9IE       +0.1     96   1.000000103
  DK0TE*      -0.1   2545   0.999999863
  DK3UA       -9.4   1152   0.999990640
  DK3WW       +0.7   3364   1.000000685
  DK9IP       -0.2   1772   0.999999761
  DK9IP-1*    -0.0   2350   0.999999965
  DL0LA       +0.1    867   1.000000119
  DL0PF*      +0.0   1913   1.000000034
  DL1HWS      +0.3    800   1.000000332
  DL8LAS*     +0.0   6339   1.000000049
  DL8TG*      -0.0   1588   0.999999998
  DM5GG       -0.6   3772   0.999999406
  DM7EE*      +0.1   2521   1.000000137
  E28AC       +4.7    185   1.000004750
  EA1RX       -2.7     69   0.999997338
  EA1URA*     -0.0   2022   0.999999974
  EA2CW       +0.3   2076   1.000000306
  ES2RR*      -0.0   3169   0.999999973
  F6IIT       -1.4    184   0.999998599
  F8DGY*      -0.1    652   0.999999942
  G0KTN       +0.2   2485   1.000000196
  G3YPP       -0.0     81   1.000000000
  G4IRN       +0.3   1403   1.000000282
  G4ZFE       +0.3   2944   1.000000293
  GI4DOH      +0.4    517   1.000000362
  HA1VHF      -0.8   1970   0.999999222
  HA2NA-5     +0.4   1127   1.000000384
  HA6PX*      -0.1   2563   0.999999929
  HA8TKS      +0.2   1531   1.000000219
  HB9BXE      +0.2   2479   1.000000243
  HB9DCO      -0.7   1780   0.999999321
  HG0Y        +5.6    244   1.000005574
  HG8A        -0.6   2790   0.999999406
  IK4VET      +0.8   3043   1.000000803
  JH7CSU1     +2.8    338   1.000002843
  JI1HFJ      -3.5    212   0.999996534
  JJ2VLY      +0.8    314   1.000000801
  JN1ILK      -0.5   1170   0.999999512
  K1RA        +0.4   2742   1.000000387
  K3PA-1*     -0.0   1468   0.999999973
  K3PA-2      -0.9    117   0.999999066
  K4PP        -0.0   1409   0.999999954
  K5TR        +1.2   1087   1.000001243
  K6FOD*      -0.0    815   0.999999979
  K7EK        +0.2    462   1.000000223
  K7MJG       +0.1    245   1.000000145
  K9IMM*      +0.0   2443   1.000000012
  K9LC*       -0.0   2313   0.999999952
  KA7OEI      +0.2    694   1.000000231
  KC4YVA      +5.3    231   1.000005265
  KH6LC       +0.3    364   1.000000258
  KM3T*       -0.0   1726   0.999999996
  KM3T-2      +0.4   2852   1.000000412
  KM3T-3      +0.3   3087   1.000000265
  KO7SS       -0.3   2293   0.999999732
  KP3CW       +0.4   1704   1.000000398
  KV4TT*      -0.1   2544   0.999999895
  LA6TPA      -2.5   1137   0.999997464
  LA7GIA      -0.2    992   0.999999827
  LB9KJ       -1.2    878   0.999998820
  LU8XW       -0.6     50   0.999999415
  LZ3CB*      -0.0    950   0.999999960
  LZ4AE       +3.3    944   1.000003312
  LZ4UX*      +0.0   1770   1.000000004
  LZ5DI       +0.6   1094   1.000000597
  LZ7AA       +0.4   1778   1.000000382
  MM0ZBH      +0.7   2713   1.000000718
  MM3NDH*     +0.0   3447   1.000000036
  MW0MUT      +0.3   2540   1.000000257
  N0OI        -2.9   1628   0.999997062
  N2QT        -0.1   1703   0.999999901
  N4ZR*       +0.1   1148   1.000000098
  N6TV        +0.4   1335   1.000000439
  N7TUG      +14.3    101   1.000014256
  N9CO*       -0.0   1829   0.999999982
  ND7K        -1.0   1773   0.999999032
  NG7M*       -0.1   1025   0.999999853
  NN3RP       +0.4    708   1.000000387
  NT6Q        +4.2    866   1.000004198
  OE6TZE*     -0.0   2355   0.999999998
  OE9GHV*     -0.1   3085   0.999999943
  OG66X       +0.1    406   1.000000149
  OH4KA       +0.2   3185   1.000000158
  OH4MFA      +0.3     64   1.000000259
  OH6BG       +4.7    290   1.000004734
  OK1FCJ*     -0.0   2949   0.999999993
  OK1HRA      -3.9   2995   0.999996072
  OK4QRO      +1.2   2020   1.000001196
  ON6ZQ       -0.5   2129   0.999999545
  OZ1BZS*     +0.1    640   1.000000131
  OZ4ADX      +0.1    247   1.000000099
  PA0MBO      +0.3    958   1.000000326
  PA8MM       -0.4   2047   0.999999647
  PE5TT*      +0.0   2056   1.000000031
  R1LB        +0.0    680   1.000000042
  R6YY*       -0.1    684   0.999999920
  RK3TD       +0.4   2627   1.000000383
  RN4WA       +0.7    824   1.000000698
  RU9CZD      -9.1   2310   0.999990912
  RW9AV       -0.8    933   0.999999224
  S50U*       -0.1   1332   0.999999896
  S53WW       -1.1   2659   0.999998947
  SE5E*       +0.1   3405   1.000000140
  SM0TCZ      -6.7    120   0.999993344
  SM7IUN*     -0.1   2925   0.999999944
  SQ5J        +3.8   1375   1.000003790
  SQ5OUO      +5.7    794   1.000005711
  SV1CDN      -0.9    126   0.999999094
  SZ1A        +0.2   1543   1.000000249
  TF3Y        +1.3   2301   1.000001263
  TF4M        -1.4   5170   0.999998571
  TI7W        -0.3   2005   0.999999696
  UA0S        +0.7   1189   1.000000695
  UD4FD       +0.6    364   1.000000611
  UY2RA       +1.0   2360   1.000000976
  V51YJ       +1.8    109   1.000001794
  VE6AO       -1.0    547   0.999999030
  VE6JY       +0.5    222   1.000000546
  VE6WZ       -1.8   1429   0.999998217
  VE7CC       +0.7    411   1.000000697
  VK2EBN      +0.0      9   1.000000000
  VK2GEL      +3.9    238   1.000003931
  VK2RH       +0.0     56   1.000000000
  VK3RASA     -1.0     97   0.999999003
  VK6ANC      -1.3    188   0.999998686
  VU2CPL      +3.3    489   1.000003346
  VY0ERC      +1.0     69   1.000000999
  W1NT-2      +0.3   2654   1.000000320
  W1NT-6      +0.3   3371   1.000000314
  W1UE        -0.4   1513   0.999999562
  W2MV        +0.5    184   1.000000463
  W2NAF       +1.2    363   1.000001169
  W3LPL       -3.8   3035   0.999996230
  W3OA*       -0.0   2781   0.999999954
  W3UA*       -0.0   3351   0.999999962
  W4AX        +4.6    360   1.000004636
  W4KAZ       -0.9   1764   0.999999062
  W6YX*       -0.0   1662   0.999999968
  W8WTS*      -0.1   1503   0.999999939
  W8WWV       -1.7   2559   0.999998317
  WA7LNW      +0.2   1282   1.000000244
  WB6BEE*     -0.0   1427   0.999999964
  WC2L*       +0.1   2298   1.000000057
  WC8GOP      +2.9    103   1.000002904
  WE9V        -0.0   1306   0.999999995
  WF7U        +2.6     50   1.000002645
  WV4P        +0.5    422   1.000000518
  WZ7I*       -0.1   3210   0.999999930
  XV9Q        +0.0      8   1.000000000
  YO2MAX      +5.9   2583   1.000005880
  YO4RDW      -6.3    229   0.999993659
  ZF9CW       -0.3   3037   0.999999707
  ZL3X        -2.5    381   0.999997547
  ZL4YL       +1.3     76   1.000001257

Last updated 2024-04-25 00:15:44 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    0424  0423  0422  0421  0420  0419  0418  0417  0416  0415
---------------------------------------------------------------------
2E0INH     -0.0  -0.0  -0.1  -0.0  -0.0  +0.1  -0.0  -0.1  -0.0  -0.0
3B8CW      -1.9  -1.8  -1.9  -2.0  -1.9  -1.8  -2.2  -2.0  -2.4  -1.9
3D2AG      +0.4  +0.5  +0.5  -0.0  +0.1  +0.3  +0.5  +0.4  +0.1  +0.0
3V8SS      -1.2  -1.4  -1.4  -1.9  -1.8  -1.6  -1.6  -1.8  -0.7  -6.1
5W1SA                  +1.4  +1.4  +1.6  +4.2                    +1.0
7N4XCV     -0.0  +0.0  +0.6  +0.5  +0.6  +0.5  +0.6  +0.7  +0.0  +0.8
7Q6M                               -2.7  -3.6                        
9M2CNC     +0.2  +0.5  +0.3  +0.7  +0.6  +0.5  +0.3  +0.7  +0.4  +0.6
AA0O       +0.2  +0.0  +0.2  +0.0  +0.2  -0.0  +0.0  +0.1  +0.2  +0.1
AA4VV      -0.1  -0.0  +0.0  -0.1  -0.2                    -0.1  -0.0
AC0C-1     +0.1  +0.0  +0.0  -0.0  -0.1  -0.0  -0.0  -0.1  +0.1  +0.0
BA6KC      +0.1  -0.0  +0.0  -0.1  -0.2  +0.2  -0.1  -0.1        +0.2
BA6KC1                       -0.2  -0.0  -0.2  +0.3  +0.0            
BD4QJP     +3.1  +2.1  +2.5  +3.1  +1.6  +2.0  +2.8  +1.7  +1.8  +3.1
BD7JNA     -0.0  -0.5  -0.1  -0.2  -0.2  -0.2  -0.2  -0.2  +0.3  +0.1
BD8CS      +0.1  -0.0  -0.0  -0.1  -0.0  -0.2  -0.0  +0.0  +0.1  -0.1
BG0AJO     +0.2  +0.1  +0.0  -0.2  +0.0  +0.2  +0.2  +0.2  +1.7  +0.1
BG4GOV     +0.1  +0.3  +0.3  +0.2  +0.2  +0.4  +0.1  +0.3  +0.0  +0.0
BG4WOM     +0.1  +0.0  +0.1  -0.0  +0.1  +0.0  -0.1  +0.2  -0.1  +0.1
BH4RRG     -0.1  +0.1  -0.1  -0.1  +0.0  +0.3  +0.0  -0.0  -0.1  +0.0
BH4RXP     -0.2  -3.7  -3.2  +0.7  -4.6  -4.9  -4.8  -4.8  -5.1  +0.6
BH4XDZ     -0.0  +0.0  +0.1  +0.1  -0.1  +0.2  +0.0  +0.1  -0.3  +0.1
BI4MPH                       +0.0  +0.1  -0.1  +0.3  +0.1  +0.0  +0.1
BI4MPH-1   +0.1  +0.0  +0.2  +0.1  +0.2  +0.0  +0.1  -0.1        +0.2
BI4RFP                             +0.1  +0.1  +0.2  +0.3  +0.0  +0.1
BI4RFP-YZ  +0.0  +0.0  -0.1  -0.1  -0.2  -0.1  +0.4  +0.1  +0.4  +0.2
BI4SSB     +0.1  +0.0  +0.3  +0.1  +0.4  +0.0  +0.3  +0.1        +0.0
CR6K       -5.0  -5.9  -5.7  -5.5  -5.8  -5.5  -5.3  -5.3  -5.1  -5.2
CX6VM      -3.6  -2.4  -2.1  -2.8  -3.1  -3.4  -4.8  -4.3  -2.8  -3.3
DC8YZ      +0.1  +0.1  +0.1  +0.0  +0.1  +0.1  +0.1  +0.2  -0.1  +0.2
DD5XX      -1.3  -1.1  -1.0  -1.5  -0.8        -1.4  -0.8  -0.8  +0.2
DE1LON     -0.2  -0.1  -0.3  -0.3  -0.3  -0.1  -0.1  -0.1  +0.1  +0.2
DF2CK      -0.3  -0.5  -0.5  -0.5  -0.0  -0.1  -0.1  +0.1  +0.2  +0.5
DF7GB      +0.1  +0.0  -0.1  +0.0  -0.0  +0.0  -0.0  +0.0  +0.1  -0.0
DJ2BC      -0.4  -0.5  -0.4  -0.5  -0.4  -0.2  -0.2  -0.3  -0.1  -0.1
DJ9IE      +0.1  +0.4  +0.2  +0.0  +0.1  +0.2  +0.0  -0.0  -0.1  +0.2
DK0TE      -0.1  +0.2  +0.2  +0.2  +0.2  +0.2  +0.4  -0.2  -0.0  +0.6
DK3UA      -9.4  -9.2 -10.0  -8.9  -7.1  -9.5  -8.6  -8.7 -10.0  -8.5
DK3WW      +0.7  +0.8  +1.0  +1.0  +1.3  +1.0  +0.9                  
DK9IP      -0.2  -0.1  -0.1  -0.1  -0.1  -0.1  -0.1  -0.1  +0.1  +0.1
DK9IP-1    -0.0  -0.1  -0.0  +0.1  -0.0  +0.1  +0.1  +0.1  +0.1  +0.1
DL0LA      +0.1  +0.2  +0.2  +0.1  +0.2  +0.0  +0.2  +0.2  +0.1  +0.3
DL0PF      +0.0  +0.1  -0.2  -0.0  +0.0  +0.0  -0.1  +0.1  +0.1  +0.5
DL1AMQ                                                           -1.7
DL1EFW                       +1.5  +1.4        +1.0  +1.0  +0.6  +1.5
DL1HWS     +0.3  +0.3  +0.3  +0.3  +0.3  +0.3  +0.3  +0.4  +0.2  +0.4
DL8LAS     +0.0  +0.1  +0.1  +0.1  +0.0  +0.1  -0.1  +0.2  +0.1  +0.3
DL8TG      -0.0  -0.0  -0.0  -0.0  -0.0  +0.0  +0.1  +0.0  +0.1  +0.0
DL9GTB                       -0.1  -0.1                              
DM5GG      -0.6  -0.6  -0.7  -0.7  -0.7                          +0.7
DM7EE      +0.1  +0.2  +0.2  +0.2  +0.2  +0.3                        
DR4W                         -2.6  -4.0  -3.5  -3.3  -3.0  -3.0  -1.3
DR5X                                     +0.3  +0.5  +0.3            
E28AC      +4.7  +4.7  +5.2  +4.4  +3.9  +3.5  +4.7  +4.8  +4.7  +4.8
EA1RX      -2.7  -1.5  -2.8  -4.9  -2.9  -4.8  -2.4  -6.9 -10.5  -9.5
EA1URA     -0.0  +0.1  +0.4  +0.8  +0.8  +1.0  +0.7  +1.2  +0.7  +1.2
EA2CW      +0.3  +0.4  +0.5  +0.7  +0.6  +0.6  +0.5  +0.5  +0.6  +0.8
EA2RCF-4                                             +0.6  +0.7  +0.6
EA4FIT                                         +0.0  +0.0        +0.0
EA5RQ                       +15.1                                    
EA5RQ/A          -0.3  +0.0  -0.1  -0.1  -0.0  +0.0  -0.1  +0.5  +0.0
ES2RR      -0.0  -0.0  -0.0  -0.1  -0.0  +0.0  -0.1  -0.0  -0.2  -0.1
F5AHD                        +0.7                                    
F6IIT      -1.4  -0.8  -0.8  -1.3  -1.0  -0.3  -1.0  -0.5  -0.7  -0.5
F8DGY      -0.1  -0.0  -3.9  -0.1  -0.1  +0.2  +0.1  +0.1  +0.2  -2.7
G0KTN      +0.2  +0.2  +0.2  +0.3  +0.4  +0.3  +0.3  +0.3  +0.3  +0.3
G3XBI                  +0.0  +0.3  +0.3  +0.1  +0.3  +0.2  +0.2  +0.0
G3YPP      -0.0  +0.2  +0.0  +0.1  +0.2  -0.2  +0.2  +0.1  +0.2  +0.3
G4AON                                          +1.0                  
G4IRN      +0.3  +0.3  +0.2  +0.4  +0.2  +0.3  +0.6  +0.6  +0.5  +0.5
G4ZFE      +0.3  +0.1  +0.2  -0.0  +0.3  +0.2  +0.2  +0.2  +0.2  +0.3
GI4DOH     +0.4  +0.4                          +0.3  +0.3  +0.1  +0.2
HA1VHF     -0.8  -0.5  -0.4  -0.4  -0.6  -0.7  -1.1  -1.9  -1.4  -0.6
HA2NA                              -0.2  -0.1                        
HA2NA-5    +0.4  +0.4  +0.6  +0.6                    +0.6  +0.1  +0.4
HA6PX      -0.1  -0.0  +0.0  -0.0  -0.0  -0.1  -0.1  -0.1  -0.0  -0.0
HA8TKS     +0.2  +0.1  +0.3  +0.2  +0.2  +0.3  +0.2  +0.2  +0.3  +0.2
HB9BXE     +0.2  +0.2  +0.2  +0.2  +0.2  +0.3  +0.1  +0.0  +0.2  +0.2
HB9DCO     -0.7  -0.4  -0.5  -0.5  -0.4  -0.5  -0.5  -0.5  -0.3  -0.3
HG0Y       +5.6  +5.4  +6.1  +5.5  +5.9  +5.9  +5.7  +6.0  +6.2  +8.2
HG8A       -0.6  -0.4  -0.4  -0.4  -0.3  -0.1  +0.0  +0.2  +0.4  +0.8
IK3STG                             +3.2  +2.2  +1.6  +1.9  +1.4  +2.1
IK4VET     +0.8  +0.4  +0.7  +1.8  +2.4  +1.6  +1.5  +2.3  +2.8  +3.3
IK7YTT                       -0.2  -0.2  -0.2  -0.7                  
IU2RPU                                               +0.0  -1.1      
IZ2CPS                       +1.1  +1.2        +1.0  +0.9  +0.5  +0.7
J68HZ                             +12.6 +11.8 +11.5 +11.7 +12.0 +11.8
JH4UTP           +0.4  +0.9  +0.1  +0.4  +1.1                        
JH7CSU1    +2.8  +3.4  +3.4  +3.1  +2.2  +2.8  +2.9  +2.5  +2.6  +2.9
JI1HFJ     -3.5  -1.7  -2.4  -3.4  -7.2  -5.0  -1.7  -8.5  +0.1  -1.6
JJ2VLY     +0.8  +0.9  +0.3  +1.9  +1.2  +1.0  +0.4  +0.9  +0.2  +1.0
JN1ILK     -0.5  -0.2  +0.0  +0.1  +0.2  -0.5  -0.1  +0.4  +0.1  +0.5
K1RA       +0.4  +0.1  +0.0  +0.0  +0.3  +0.5  +0.7  +0.6  +0.7  +0.5
K2PO/7           +0.2  +0.4  +0.4  +0.5  +0.3  +0.7  +0.6  +0.2      
K3PA-1     -0.0  -0.0  +0.1  -0.1  -0.1  +0.1  +0.0  -0.1  -0.0  -0.0
K3PA-2     -0.9  -0.9  -0.8  -2.0  -1.5  -1.4  -1.1  -0.6  -0.6  -1.2
K4PP       -0.0  -0.3  -0.5  -0.2  +0.7  +0.5  +0.9  +1.0  +0.9  +0.6
K5EM                                                       -0.0  +0.0
K5TR       +1.2  +0.8  +0.9  +2.4  +2.4  +0.5  +0.9  +1.0  +0.3  +1.1
K6FOD      -0.0  +0.1  +0.1  +0.2  +0.0  -0.1  +0.0  +0.0  +0.1  -0.2
K7EK       +0.2  +0.5  +0.3  +0.4  +0.5  +0.5  +0.9  +1.1  +0.5  +0.4
K7MJG      +0.1  -0.1  +0.4  +0.5  +0.4  +0.2  +0.7  +0.4  +0.1  -0.0
K7RUT                                                -1.3            
K9IMM      +0.0  +0.1  +0.1  +0.0  -0.0  +0.1  -0.0  +0.2  -0.0  +0.0
K9LC       -0.0  +0.1  +0.1  +0.1  +0.0  -0.0  +0.0  +0.1  +0.2  +0.0
KA7OEI     +0.2  +0.4  +0.2  +0.4  +0.4  +0.2  +0.3  +0.3  +0.2  +0.3
KC4YVA     +5.3  +5.0  +6.0  +5.7  +6.2  +5.1  +5.4  +5.6  +4.4  +4.8
KH6LC      +0.3  +0.2  +0.2  +0.4  +0.2  +0.2  +0.6  +0.3  +0.4  +0.2
KM3T       -0.0  -0.0  -0.0  -0.0  -0.1  -0.1  +0.0  -0.1  -0.2  -0.0
KM3T-2     +0.4  +0.3  +0.4  +0.5  +0.5  +0.2  +0.4  +0.3  +0.5  +0.4
KM3T-3     +0.3  +0.2  +0.2  +0.3  +0.3  +0.1  +0.3  +0.2  +0.3  +0.2
KO7SS      -0.3  -0.1  -0.2  -0.5  -0.5  -0.4  -0.6  -0.9  -0.9  -0.8
KP3CW      +0.4  +0.3  +0.3  +0.4  +0.5  +0.3  +0.3  +0.3  +0.3  +0.3
KV4TT      -0.1  -0.1  -0.1  +0.0  -0.0  +0.0  -0.1  +0.0  +0.0  -0.1
LA6TPA     -2.5  -2.2  -3.5  -2.6  -2.7  -2.9  -2.9  -2.7  -3.0  -2.5
LA7GI                              -0.1                              
LA7GIA     -0.2  -0.1  -0.0  -0.2  +0.0  -0.1  -0.1  -0.1  +0.0  +0.0
LB9KJ      -1.2  -1.0  -1.0  -1.1  -1.4  -1.0  -1.3  -0.9  -1.5      
LU3MG                                                            +0.0
LU8XW      -0.6  -1.1  -2.6  -2.2  -2.4  -2.7  -1.9  -0.6  -1.0  -1.3
LY2XW                        +0.5  +0.4                              
LY3G                                           +0.3              -5.1
LZ3CB      -0.0  -0.1  +0.0  +0.0  -0.0  -0.0  -0.1  -0.0  -0.0  +0.0
LZ4AE      +3.3  +3.1  +2.7  +3.3  +3.4  +3.2  +3.5  +3.3  +3.1  +3.1
LZ4UX      +0.0  +0.0  -0.1  +0.0  -0.0  -0.0  +0.0  -0.1  -0.1  -0.0
LZ5DI      +0.6  +0.4  +0.5  +0.6  +0.5  +0.4  +0.5  +0.7  +0.5  +0.6
LZ7AA      +0.4  +0.4  +0.5  +0.5  +0.5  +0.5  +0.6  +0.7  +0.7  +1.0
M0JYE                                    -8.8                   -11.1
MM0ZBH     +0.7  +0.5  -0.1  +0.6  +2.2  +0.2  +0.2  +0.1  -0.3  -0.2
MM3NDH     +0.0  -0.0  -0.1  -0.0  +0.0  -0.3  +0.0  +0.0  +0.0  +0.0
MW0MUT     +0.3  +0.2  +0.3  +0.1  +0.2  +0.1  +0.2  +0.0  +0.2  +0.1
N0OI       -2.9  -0.8              +0.1  +0.1  +0.5  +0.3  +0.0  -0.3
N2QT       -0.1  -0.0  +0.0  +0.1  +0.2  +0.2  +0.3  +0.1  +0.3  +0.2
N4ZR       +0.1  -0.0  -0.1  -0.1  +0.1        +0.1  +0.0  +0.1  +0.0
N6TV       +0.4  +0.3  +0.4  +0.6  +0.4  +0.4  +0.6  +0.4  +0.4  +0.3
N7TUG     +14.3 +14.1 +14.1 +14.0 +14.5 +13.7 +14.3 +13.9 +14.2 +14.2
N9CO       -0.0  -0.0  -0.1  -0.1  -0.1  +0.1  +0.1  +0.3  -0.1  -0.0
ND7K       -1.0  -0.7  -0.9  -1.2        -0.9  -1.2  -1.2  -1.1  -1.6
NG7M       -0.1  -0.2  -0.2  -0.4  -0.3  -0.4  -0.4  -0.2  -0.4  -0.3
NN3RP      +0.4  +0.1  +0.2  +0.5  +0.4  +0.2  +0.9  +0.4  +0.8  +0.3
NT6Q       +4.2  +3.5  +4.4  +4.0  +3.8  +3.6  +4.0  +2.7  +2.6  +3.2
NU6XB                              +0.7  +0.4  +0.3  +0.3  +0.5  +0.5
OE6ADD                       -0.1  -0.0  +0.1  +0.2  +0.1  +0.0  +0.2
OE6TZE     -0.0  +0.1  +0.1  +0.2  +0.1  +0.2  +0.1  +0.1  +0.0  +0.2
OE9GHV     -0.1  -0.0  -0.1  -0.1  -0.1  -0.0  -0.1  -0.1  -0.0  -0.0
OG66X      +0.1  +0.1  -0.1  -0.1  +0.1  -0.2  +0.0  -0.1  -0.3  +0.1
OH4KA      +0.2  -0.1  -0.2  -0.1  -0.1  -0.3                    +0.2
OH4MFA     +0.3  +0.4  +0.1                                          
OH6BG      +4.7  +4.9  +3.0  +4.6  +3.6  +4.4  +4.5  +5.0  +5.0  +4.7
OK1FCJ     -0.0  -0.0  +0.0  -0.1  +0.0                              
OK1HRA     -3.9  -4.0  -4.2  -4.2  -4.1  -4.1  -4.3  -3.9  -3.4  -3.5
OK4QRO     +1.2  +1.2  +1.5  +1.7  +1.8  +1.4  +1.4  +1.5  +1.1  +1.7
ON4EM                  +0.2        -0.3              -0.8            
ON6ZQ      -0.5  -0.4  -0.5  -0.4  -0.7  -0.3  -0.3  -0.3  -0.3  -0.1
OZ1AAB                       -0.1  -0.0  -0.0  +0.0  -0.1  -0.0  -0.0
OZ1BZS     +0.1  +0.1  +0.0  +0.1  +0.1  +0.2  -0.0  +0.1            
OZ4ADX     +0.1  +0.2  +0.2  -0.1  +0.1        +0.3  +0.1  -0.0  +0.2
P40L                                                             +1.2
PA0MBO     +0.3  +0.3  +0.2  +0.3  +0.3  +0.3  +0.3  +0.3  +0.2  +0.4
PA5KT                        -2.5  -1.7  -1.4                        
PA8MM      -0.4  -0.2        -0.2  -0.3  -0.1  -0.1  -0.1  -0.4      
PE5TT      +0.0  -0.2  +0.3  -0.2  +0.3  -0.1  -0.3  +0.1  -0.1  -0.0
PJ2A                                                             +0.0
R1LB       +0.0  -0.0  -0.0  -0.2  +0.1  -0.2  +0.0  +0.0  -0.1  +0.1
R6YY       -0.1  -0.1  -0.2  -0.1  +0.1  -0.1  +0.4  +0.2  -0.1  -0.2
RK3TD      +0.4  +0.3  +0.3  +0.5  +0.4  +0.1  +0.8  +0.4  +0.1  +0.2
RK3TD-2                      +0.4  +0.4  +0.3  +0.4  +0.4  +0.3  +0.4
RN4WA      +0.7  +0.6  +0.6  +1.1  +1.4  +0.9  +0.9  +1.0  +0.9  +1.0
RU9CZD     -9.1  -8.1  -4.4  -2.7  -1.1  -3.2  -3.6  -5.0  -6.8  -6.7
RW9AV      -0.8  -0.8  -0.7  -0.7                    -0.8  -1.0  -0.7
S50U       -0.1  -0.0  -0.0  -0.1  +0.1  +0.3  +0.1  +0.0  +0.1  +0.1
S53A             +0.9  +1.2  +1.5  +1.6  +1.2  +1.4  +1.3  +1.1  +1.6
S53WW      -1.1  -0.9  -1.0  -1.0  -1.0  -0.7  -0.6  -0.4  -0.0  +0.3
SE5E       +0.1  +0.0  +0.2  +0.4  +0.3  +0.0  +0.1  +0.1  +0.1  +0.2
SM0TCZ     -6.7  -7.2  -7.0  -3.6  -2.4  -3.2  -3.6  -2.5  -4.9  -0.2
SM7IUN     -0.1  -0.2  -0.2  -0.1  -0.1  -0.2  -0.0  +0.0  -0.1  +0.0
SQ5J       +3.8  +3.4  +3.1  +3.8  +3.9  +3.5  +3.6  +3.7  +3.2  +3.8
SQ5OUO     +5.7  +6.3  +5.2  +6.0  +7.0  +6.7  +5.9  +5.9  +5.2  +5.8
SV1CDN     -0.9  -0.6  -0.5  -1.1  -1.1  -1.2  -0.4  -0.8  -1.1  -0.7
SZ1A       +0.2  +0.5  +0.0  -0.5  +1.4  -0.8  -0.4  -0.3  -0.6  +0.3
TF3Y       +1.3  +1.2  +1.4  +1.7  +1.7  +1.2  +1.2  +1.2  +1.1  +1.2
TF4M       -1.4  -1.4  -1.4  -1.6  -1.5  -1.5  -1.3  -1.2  -1.2  -1.6
TI7W       -0.3  -0.3  -0.2  -0.4  -0.3  -0.3  -0.4  -0.3  -0.3  -0.3
TZ4AM            -0.4  -1.6  -3.1  -1.5  -0.1  +0.6        -6.4  -3.0
UA0S       +0.7  +1.0  +0.7  +1.0  +1.2  +1.4  +1.1  +1.4  +1.2  +1.2
UD4FD      +0.6  +1.2  +1.3  +1.5  +1.4  +1.4  +0.8  +0.6  +0.3  +0.3
UY2RA      +1.0  +1.1  +0.9  +1.4  +1.4  +1.3  +1.8  +1.8  +1.0  +1.5
V51YJ      +1.8  +1.1  +1.2  +2.1  +1.6  +1.7  +1.8  +2.3  +2.2  +1.3
VE6AO      -1.0  -0.8  -0.9  -1.4  -1.2  -1.4  -1.8  -2.0  -0.8  -0.7
VE6JY      +0.5  +0.5  +0.5  +0.5  +0.7  +0.8  +0.2  +0.6  +1.4  +0.4
VE6WZ      -1.8  -6.1  -5.0  -2.0  -3.4  -6.3  -1.2  -5.8  -7.8  -5.6
VE7CC      +0.7  +0.8  +0.8  +0.9  +0.7  +0.5  +0.6  +0.6  +0.4  +0.5
VK2EBN     +0.0  -1.8        -0.3  -0.1                    +0.0  +0.0
VK2GEL     +3.9  +4.1  +3.7  +3.6  +3.3  +3.3  +4.4  +3.3  +4.2  +4.6
VK2RH      +0.0  -0.1  +0.2  -0.2  +0.1  +0.0  -0.1  -0.2  +0.0  +0.1
VK3RASA    -1.0        -0.8  -1.2  -1.0  -1.6  -0.8  -0.4  -0.7  -0.1
VK6ANC     -1.3  -1.3  -1.0  -1.0  -1.6  -1.5  -0.9  -0.5  -1.0  -0.9
VR2FUN-74                          +6.3  +6.2  +6.0  +6.3  +6.5  +6.1
VR2FUN-77        +0.3  +0.2  +0.1  +0.1  +0.0  +0.1  -0.1        +0.2
VU2CPL     +3.3  +3.2  +3.5  +3.0  +3.0  +2.9  +3.2  +2.8  +2.2  +3.3
VY0ERC     +1.0  +0.4  +0.0  +0.8  +0.8  +0.9  +0.0  +0.0        +0.7
W1NT-2     +0.3  +0.3  +0.3  +0.5  +0.3        +0.4  +0.3  +0.4  +0.3
W1NT-6     +0.3  +0.3  +0.2  +0.4  +0.4  +0.2  +0.3  +0.2  +0.3  +0.3
W1UE       -0.4  -5.4  -2.4  -5.4  -5.6  -5.6  -5.3  -5.8  -5.4  -5.3
W2MV       +0.5  -1.9  +0.1  +0.6  +0.3  -0.1  +0.5  +0.5  +0.6  +0.6
W2NAF      +1.2  +0.9  +1.0  +1.3  +1.5  +1.0  +1.2  +1.3  +0.9  +1.1
W3LPL      -3.8  -3.9  -3.7  -3.8  -4.0  -3.5  -4.0  -3.3  -3.0  -3.5
W3OA       -0.0  -0.0  +0.0  +0.0  +0.1  -0.0  -0.0  +0.1  +0.0  +0.0
W3UA       -0.0  -0.0  -0.0  -0.1  -0.1  -0.1  -0.1  -0.0  +0.0  -0.1
W4AX       +4.6  +4.3  +4.9  +4.8  +4.6  +4.7  +4.6  +4.9  +4.6  +4.6
W4KAZ      -0.9  -2.0  -1.7        -0.5  -0.3  -0.4  -0.4  -0.2      
W6BB                               +0.6  +0.6  +0.5  +0.6  +0.6  +0.6
W6YX       -0.0  +0.1  +0.3  +0.2  +0.2  -0.0  +0.3  +0.1  +0.0  -0.2
W8WTS      -0.1  -0.0  +0.1  +0.2  +0.1  +0.2  +0.2  +0.0  +0.1  +0.2
W8WWV      -1.7  -1.2  -1.2  -1.8  -1.8  -1.2  -1.4  -1.4  -1.1  -1.4
WA7LNW     +0.2  +0.2  +0.2  +0.2  +0.2  +0.1  +0.1  -0.1  -0.4  -0.3
WB6BEE     -0.0  +0.0  +0.0  +0.0  -0.0  +0.0  +0.1  +0.2  -0.1  -0.0
WC2L       +0.1  +0.0  +0.1  +0.2  +0.2  +0.0  +0.2  +0.4  +0.0  +0.1
WC8GOP     +2.9  +3.5  +5.4  +4.7  +4.6  +4.8  +3.5  +6.4  +2.6  +5.8
WE9V       -0.0  +0.1  -0.3  +0.6  -0.1  -0.3  -0.1  -0.1  +0.5  +0.1
WF7U       +2.6                                            +1.9  +4.0
WV4P       +0.5  +0.4  +0.7  +0.8  +0.8  +0.5  +0.7  +0.7  +0.6  +0.3
WZ7I       -0.1  -0.1  +0.0  -0.1  -0.1  -0.1  +0.1  -0.1  +0.0  +0.0
XV9Q       +0.0  +0.0        -0.3                    +0.0  +0.0  +0.0
YO2MAX     +5.9  +6.0  +5.7  +6.1  +6.0  +6.0  +6.0  +5.9  +5.5  +6.0
YO4RDW     -6.3  -8.3  -3.6  +0.5  +0.4  +0.6  +0.5  +0.7  +0.4  +0.5
YU7GM                        +0.6  +0.6                          +0.4
ZF9CW      -0.3  -0.2  -0.2  -0.2  -0.5  -0.2  -0.6  -0.4  -0.3  -0.6
ZL3X       -2.5  -0.3  -8.0  -0.2  -0.7  -0.4  -0.8  -0.9  -0.2  -0.2
ZL4YL      +1.3  +0.5  +0.7  +1.2  +1.4  +1.2  +1.3  +1.4  +0.6  +0.7

Last updated 2024-04-25 00:15:55 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 ES2RR KM3T LZ3CB LZ4UX MM3NDH OE9GHV WB6BEE 

Last updated 2024-04-25 00:15:55 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.