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 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-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.