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 here is based on archived RBN data from the previous day, 00:00 to 23:59 UTC. When making adjustments, this means that 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.
The software used to calculate the tables below can be found here. It runs as a cron job in an Ubuntu container on my server and uploads to this WordPress site shortly after midnight UTC every night.
The calculation of deviation estimates 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 reference drastically increases the geographical coverage of the algorithm, in turn increasing the number of qualifying spots, thus leading to 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.
311796 RBN spots between 2021-12-01 00:00 and 23:59 UTC. 77125 spots (24.7%) were from reference skimmers (*). Average spot flow was 217 per minute from 173 active CW skimmers. 131332 spots from 168 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 -0.1 32 0.999999851 3D2AG +0.0 109 1.000000022 3V8SS -1.2 1465 0.999998795 5W1SA +1.0 281 1.000001031 9A1CIG +4.3 327 1.000004317 9M2CNC +1.5 56 1.000001505 AA4VV* -0.1 1844 0.999999925 AC0C-1 -0.0 1645 0.999999952 BA7QT +0.0 9 1.000000000 BG4GOV -0.4 19 0.999999623 BG4WOM -7.5 121 0.999992540 BG8DIV -4.3 41 0.999995653 BH4RRG +21.7 11 1.000021687 CX6VM +0.6 59 1.000000600 DD5XX* +0.2 882 1.000000163 DE1LON -0.2 1227 0.999999755 DF2CK* -0.0 608 0.999999965 DF4XX -0.6 890 0.999999358 DF7GB* +0.1 1131 1.000000064 DJ2BC -0.3 1063 0.999999658 DK0TE +1.0 957 1.000001050 DK3UA* +0.1 474 1.000000122 DK9IP* -0.2 916 0.999999804 DL0LA +0.9 1064 1.000000884 DL0PF* -0.2 748 0.999999845 DL1AXX* +0.2 1207 1.000000242 DL1HWS +2.0 1147 1.000001959 DL3DTH* +0.2 1429 1.000000199 DL6KBG +0.0 5 1.000000000 DL8TG -1.1 1446 0.999998912 DL9GTB -0.8 1440 0.999999212 DM6EE -0.4 1257 0.999999582 DM7EE +0.4 638 1.000000407 DO4DXA* -0.1 676 0.999999875 DR4W -1.5 349 0.999998488 E28AC +2.0 230 1.000002033 E76C +20.2 572 1.000020244 EA1URA +0.5 915 1.000000478 EA5WU -0.8 1307 0.999999181 ES5PC* -0.1 1508 0.999999938 ET3AA +0.0 13 1.000000000 EY8ZE -0.4 637 0.999999556 F4EGZ +0.8 993 1.000000777 F6IIT -3.5 1411 0.999996490 G0KTN +0.4 1152 1.000000431 G4AON +0.5 149 1.000000510 G4HSO -0.5 1164 0.999999482 G4ZFE* -0.0 942 0.999999965 GI4DOH -0.4 526 0.999999623 GM6DX +0.6 192 1.000000557 HA1AG +0.4 459 1.000000443 HA1VHF -1.3 1412 0.999998689 HA7GN -0.8 420 0.999999151 HA8TKS* +0.1 559 1.000000146 HB9BXE* -0.0 1326 0.999999994 HB9DCO* -0.0 1044 0.999999980 HB9JCB +1.4 1088 1.000001359 HG8A +0.1 1360 1.000000095 HS8KVH +2.5 64 1.000002460 IK3STG +14.3 81 1.000014282 IK4VET -1.4 1842 0.999998639 JA4ZRK +0.0 6 1.000000000 JH7CSU1 +3.0 67 1.000002990 JI1HFJ -4.3 10 0.999995728 JJ2VLY -0.5 27 0.999999471 JQ1BVI -0.6 31 0.999999387 K1TTT -0.7 1345 0.999999297 K2PO/7 +0.6 392 1.000000580 K3LR -1.0 41 0.999998962 K3PA-1* +0.0 1274 1.000000038 K4PP -0.5 763 0.999999470 K5TR +0.5 237 1.000000541 K7EG +1.3 502 1.000001291 K7MJG -8.9 322 0.999991148 K9IMM* -0.0 1500 0.999999960 K9LC -0.3 1599 0.999999742 K9TM-4 +1.1 1233 1.000001137 KC0VKN -0.8 553 0.999999179 KC4YVA +5.1 614 1.000005092 KD2OGR* -0.0 595 0.999999971 KD7YZ* -0.1 1682 0.999999928 KH6LC +0.2 98 1.000000218 KI4PAD -10.6 689 0.999989444 KM3T* -0.0 2219 0.999999979 KM3T-1 +0.2 492 1.000000173 KM3T-2 -1.8 2281 0.999998178 KO7SS -0.8 1674 0.999999152 KO7SS-7* -0.0 1032 0.999999966 KP2RUM* +0.0 1515 1.000000039 LA6TPA -1.6 345 0.999998422 LZ3CB -0.0 543 0.999999959 LZ4UX* +0.1 628 1.000000061 LZ7AA +0.2 856 1.000000241 M7RMZ +0.0 11 1.000000000 MM0ZBH -1.6 1627 0.999998382 MW0MUT +0.8 1476 1.000000756 N2QT +1.7 1966 1.000001671 N4RLI -1.9 902 0.999998134 N4ZR* +0.3 327 1.000000320 N6TV +0.1 683 1.000000052 N6WIN-7* +0.0 1366 1.000000002 N7TUG +4.1 162 1.000004065 N9MKC* +0.1 1382 1.000000072 NA0B* -0.0 376 0.999999962 NC7J* -0.1 845 0.999999949 NN3RP +0.5 648 1.000000548 OE9GHV* +0.0 1733 1.000000039 OG66X -4.0 19 0.999995994 OH4KA -3.7 766 0.999996278 OH6BG* +0.1 1793 1.000000091 OH8KA +3.2 958 1.000003232 OK1FCJ* +0.0 1201 1.000000046 OK1FPS -0.4 246 0.999999585 OL7M -0.6 400 0.999999415 ON6ZQ -0.5 1095 0.999999482 PA0MBO* +0.3 479 1.000000263 PA1T +11.6 53 1.000011554 PJ2A -1.4 89 0.999998576 R9IR -0.5 122 0.999999455 RK3TD* +0.2 701 1.000000194 RN4WA -0.4 607 0.999999611 RW9AV -0.3 184 0.999999707 S50ARX +0.8 372 1.000000773 S50U +1.2 297 1.000001215 SE5E -2.0 1698 0.999998018 SJ2W* -0.1 678 0.999999949 SM0TCZ +1.0 232 1.000000982 SM6FMB* -0.0 774 0.999999964 SM7IUN -0.2 1412 0.999999795 SP8R -6.6 395 0.999993412 SV8RV +0.4 728 1.000000363 TF3Y +0.5 680 1.000000473 TF4X -1.6 581 0.999998382 UA0S -3.7 107 0.999996268 UA4M +4.1 972 1.000004128 UP2L -3.4 361 0.999996555 UT4U -4.4 355 0.999995621 V51YJ +1.2 154 1.000001175 VE2WU* +0.1 422 1.000000068 VE6AO -1.3 354 0.999998715 VE6WZ +2.6 853 1.000002588 VE7CC +0.4 435 1.000000364 VK2GEL +4.1 34 1.000004147 VK3RASA +2.1 106 1.000002117 VK4CT -0.3 393 0.999999716 VK6ANC -0.3 178 0.999999677 VU2PTT -0.0 48 0.999999984 W1NT-2 -1.2 1785 0.999998772 W1NT-6 -0.7 2328 0.999999279 W2MV +1.0 178 1.000000958 W2NAF +0.9 1769 1.000000883 W3LPL +1.0 2182 1.000001046 W3OA* +0.1 1474 1.000000075 W3RGA -0.8 542 0.999999212 W3UA* -0.2 1156 0.999999844 W4AX +4.5 504 1.000004465 W4KAZ -1.6 222 0.999998380 W6YX +1.3 1313 1.000001306 W7HR +1.0 352 1.000000996 W8WTS -1.8 1041 0.999998163 W8WWV +0.4 1528 1.000000436 WA7LNW +0.7 1225 1.000000733 WC2L* -0.1 1393 0.999999914 WE9V +0.3 1598 1.000000293 WS3W +1.1 1501 1.000001093 WZ7I* -0.0 1992 0.999999993 ZL2BR -7.5 19 0.999992492 ZL4YL +1.5 281 1.000001533 Last updated 2021-12-02 00:15:28 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 1201 1130 1129 1128 1127 1126 1125 1124 1123 1122 --------------------------------------------------------------------- 3B8CW -0.1 -0.1 +0.1 +0.4 +0.3 +0.2 +0.1 -0.5 +0.4 +0.3 3D2AG +0.0 +0.0 +0.0 +0.0 +0.1 +2.0 -0.1 +0.1 -0.3 +0.8 3V8SS -1.2 -1.8 -1.7 -1.3 -1.7 -3.5 -0.9 -0.8 -0.6 -0.5 5W1SA +1.0 +0.7 +0.5 +0.7 +1.0 +0.7 +0.8 +0.8 +0.6 +0.1 7N4XCV +1.9 +3.6 +2.0 +0.0 9A1CIG +4.3 +4.3 +4.0 +3.8 +3.5 +3.1 +3.1 +4.5 +4.0 +4.1 9G2DX +1.5 +1.0 9M2CNC +1.5 +1.8 +0.7 +2.1 +1.7 +0.2 +0.2 +0.7 +0.6 +1.3 9W2RUT +0.0 +0.0 -0.4 +0.3 AA4VV -0.1 +0.0 -0.0 -0.3 -0.1 +0.1 +0.0 -0.1 AC0C-1 -0.0 +0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.0 +0.2 -0.3 BA1DU +0.0 +0.4 +0.1 BA7QT +0.0 -0.6 +0.0 +0.2 +0.0 BD5XM +3.7 +2.6 +3.3 +2.8 +2.2 +1.8 +4.2 BD7DT +19.9 +18.9 +18.5 +17.8 +20.0 +17.6 +20.5 +19.4 BD7JNA -0.7 +0.4 -0.4 -3.0 +3.6 -1.4 BD7LAE +0.2 +0.2 -13.1 -14.4 BD7LLL -16.2 -12.8 -13.8 -17.9 -20.8 BD8CS +0.4 +0.3 +0.2 +0.0 -0.0 +0.2 -0.1 BG0ARE +20.9 +20.3 +20.7 +21.1 +14.3 BG4GOV -0.4 -1.0 -6.1 +0.8 +0.9 -0.2 -0.4 -3.1 -0.6 +0.0 BG4WOM -7.5 -6.4 -4.6 -4.7 -5.5 -7.6 -7.2 -7.2 -6.8 -7.5 BG6SNJ +0.0 -0.3 -0.1 +0.4 +0.0 -0.0 -0.0 -0.5 +0.4 BG6TDY -2.4 -0.1 -0.1 +0.3 +0.1 +0.4 +0.7 +1.3 +1.2 BG8DIV -4.3 -5.0 -4.7 -4.7 -4.8 -3.6 -5.3 -4.3 -4.5 -4.1 BG8PA +0.0 +0.1 -0.0 +0.0 BH3BBJ +4.3 -1.8 BH4DEG +6.5 BH4RRG0 -14.2 -14.3 -13.2 -12.7 -3.4 -3.0 -1.5 -1.3 BH4RRG1 +10.3 +9.0 +11.0 +13.4 +25.6 +7.6 +6.1 +12.7 BH4RRG +21.7 BH4XDZ +1.3 +1.1 -1.5 +0.8 +0.0 BY1CY +0.0 CT7ANO -0.8 -0.7 -0.7 -0.7 -0.5 CX6VM +0.6 +0.4 +1.0 +1.4 +1.2 +1.0 +1.6 +0.7 +0.7 +0.8 CX7ACH +2.9 +2.1 DD0VS +6.0 +2.4 DD5XX +0.2 +0.2 +0.1 +0.2 +0.1 +0.1 -0.0 +0.1 +0.1 +0.0 DE1LON -0.2 -0.4 +0.1 -0.0 +0.0 -0.3 -0.3 -0.5 -0.1 -0.1 DF0RW -1.4 -6.1 -1.9 -2.6 -2.3 -2.4 DF2CK -0.0 -0.8 -0.0 -0.2 -0.3 -0.0 -0.4 -0.1 -0.3 DF4XX -0.6 -0.8 -0.9 -0.8 -0.4 -0.3 -0.5 -0.3 -0.4 -1.2 DF7GB +0.1 +0.1 -0.1 +0.0 +0.0 +0.0 +0.0 +0.0 -0.0 -0.1 DH3AKA +1.9 +0.3 +0.7 +1.5 +1.6 DJ2BC -0.3 -0.5 -0.4 -0.3 -0.4 -0.5 -0.5 -0.6 -0.6 -0.6 DJ9FBA +8.0 +6.2 +7.2 DK0TE +1.0 +1.0 +1.1 +2.0 +2.1 +1.2 +1.5 +1.5 +1.4 +1.4 DK1MAX +6.1 +5.4 DK3UA +0.1 +0.1 -0.1 -0.2 -0.2 -0.2 -0.0 -0.3 -0.3 -0.4 DK9IP -0.2 -0.0 -0.1 -0.2 -0.2 -0.2 -0.0 -0.1 -0.1 -0.2 DL0LA +0.9 +0.9 +0.7 +1.5 +1.6 +0.9 +1.0 +0.9 +1.0 +1.0 DL0PF -0.2 -0.2 +0.0 +0.2 -0.4 -0.2 -0.5 -0.4 -0.3 -0.2 DL1AMQ +0.9 +1.1 -1.6 DL1AXX +0.2 +0.1 -0.1 -0.1 +0.0 -0.0 -0.2 -0.3 DL1HWS +2.0 +1.8 +0.7 +2.5 +1.2 -1.3 -1.2 -1.1 -0.9 -1.0 DL3DTH +0.2 +0.3 +0.1 +0.2 +0.2 +0.1 +0.1 +0.1 +0.1 +0.1 DL6KBG +0.0 +0.3 +0.4 +0.1 DL6ZB -0.2 -0.3 DL8LAS +7.1 +7.3 +1.4 +0.6 +0.9 +1.0 +0.9 +0.9 DL8TG -1.1 -0.9 -1.1 -1.3 -1.3 -0.9 -0.7 -1.0 -1.0 -1.0 DL9GTB -0.8 -1.1 -0.3 -0.2 +0.3 -0.5 -0.3 -0.1 +0.0 +0.1 DM6EE -0.4 -0.1 -0.6 -1.1 -0.0 -0.2 +0.1 -0.7 -0.6 -0.9 DM7EE +0.4 +0.5 +0.5 +0.8 +1.0 +0.3 +0.6 +0.5 +0.7 +0.5 DO4DXA -0.1 -0.2 +0.0 -0.6 -0.7 -0.3 -0.1 -0.1 -0.0 -0.1 DR4W -1.5 -2.0 -1.5 -1.7 -2.1 -1.5 -1.6 -1.4 -1.5 -1.2 DU3TW +7.7 E28AC +2.0 +2.0 +2.3 +3.1 +3.0 +2.4 +2.4 +3.6 +2.6 E76C +20.2 +19.2 +20.7 +21.4 +21.5 +21.3 +20.7 +20.2 +22.4 EA1URA +0.5 +0.5 +0.3 +0.3 +2.1 +13.3 -0.0 +0.1 +9.5 +14.3 EA5WU -0.8 -0.8 -1.1 -1.2 -0.9 -0.5 -0.7 -0.5 -0.5 ES5PC -0.1 +0.0 -0.1 +0.0 +0.0 -0.1 +0.1 +0.0 -0.0 +0.0 ET3AA +0.0 +0.3 +0.0 +0.6 +0.5 +0.9 +1.0 +0.3 +0.8 EY8ZE -0.4 -0.2 -0.4 -0.2 -0.6 -0.9 -1.0 -1.2 -1.2 F4EGZ +0.8 +1.1 +0.6 +0.7 +0.8 +0.4 +0.0 +0.6 +0.8 F4VSQ +5.0 +5.0 +3.1 +4.7 +4.6 +4.5 +5.0 F5AHD -3.6 -10.9 F6IIT -3.5 -6.0 -5.7 -4.1 -4.8 -5.0 -5.1 -3.8 -3.7 -4.7 G0KTN +0.4 +0.3 +0.1 +0.4 +0.5 +0.2 G3BJ +1.0 G3WW +0.0 +0.0 +0.0 G3XBI +0.5 +0.2 +0.3 +0.2 +0.1 +0.3 +0.2 G4AON +0.5 +1.0 +0.7 +1.0 +1.0 +1.1 G4HSO -0.5 -0.6 -1.3 -1.6 -1.6 -0.6 -0.6 -0.5 -0.4 -0.9 G4ZFE -0.0 -0.1 -0.4 -0.5 -0.5 -0.2 -0.1 -0.3 -0.1 -0.3 GI4DOH -0.4 -0.4 +0.1 -0.2 -0.4 +0.0 +0.9 +0.5 +0.6 +0.4 GM6DX +0.6 +0.8 +0.3 +0.8 +0.8 +0.4 +0.9 +0.8 +0.3 +0.3 HA1AG +0.4 +0.5 +1.2 +1.5 +1.3 +0.8 +1.0 +0.1 HA1VHF -1.3 -1.2 -1.0 -1.4 -1.4 -1.0 -0.9 -0.7 -0.6 -0.7 HA5PP +2.3 +2.0 +0.0 +0.6 HA6PX -4.9 -4.9 -5.2 -5.5 -4.6 -3.5 -2.3 -1.7 HA7GN -0.8 -0.9 +0.1 +0.1 -0.5 -0.4 -0.4 -0.3 HA8TKS +0.1 -0.1 +0.1 +0.2 +0.1 -0.0 -0.1 +0.0 +0.1 +0.1 HB9BXE -0.0 +0.2 +0.0 -0.2 -0.2 -0.2 +0.0 -0.1 +0.1 +0.1 HB9DCO -0.0 -0.0 -0.0 -0.1 -0.1 +0.1 -0.0 +0.0 -0.0 +0.0 HB9JCB +1.4 +1.6 +1.5 +2.4 +2.3 +1.4 +1.5 +1.5 +1.6 +1.5 HB9RB -5.9 HG8A +0.1 -0.4 -0.3 -1.7 -1.6 -0.5 -0.3 -0.8 -0.3 -0.0 HL1VAU +3.0 HS8KVH +2.5 +1.4 +2.3 +3.5 +4.6 +3.0 +2.6 +2.5 +3.0 HS/F8UKP -1.1 -1.5 -0.8 -0.4 -2.9 -1.3 -0.7 II9P +0.8 IK1PMR +5.1 IK2LFF +4.2 +2.9 +2.6 IK3STG +14.3 +14.5 +15.0 +15.5 +15.4 +14.8 +14.2 +14.2 +14.8 +14.3 IK4VET -1.4 -1.6 -1.9 -1.7 -1.4 -1.4 -1.4 -1.3 -1.0 -1.4 JA4ZRK +0.0 -1.4 +0.0 +0.1 +0.1 -1.2 +0.0 +1.1 +0.0 +0.0 JG1DLY -0.9 -0.5 +1.1 JH4UTP -0.9 -1.0 -1.5 -0.3 JH7CSU1 +3.0 +3.2 +3.3 +4.4 +4.1 +3.7 +3.6 +4.1 +3.0 +3.7 JI1HFJ -4.3 -3.9 -5.1 -6.1 -7.0 -4.9 -4.6 -4.1 -4.9 JJ2VLY -0.5 -2.3 -3.0 +0.4 +1.1 -1.7 -2.3 -0.6 -0.6 JQ1BVI -0.6 +0.4 -1.0 -0.9 -0.9 -0.4 -0.4 -0.5 +0.0 -0.2 K1TTT -0.7 -0.9 -0.6 -0.6 -0.4 -0.3 -0.4 -0.6 -0.6 -0.4 K2PO/7 +0.6 +0.8 +1.0 +0.8 +0.8 +0.3 +0.1 +0.3 +0.2 +0.3 K3LR -1.0 +0.1 +0.2 -1.2 -1.1 +0.3 +0.4 -0.2 +0.5 +0.3 K3PA-1 +0.0 -0.0 -0.1 +0.1 +0.0 -0.0 -0.0 +0.1 -0.0 +0.0 K4PP -0.5 -0.4 -0.4 -0.5 -0.5 -0.2 -0.4 -0.5 -0.5 -0.4 K5TR +0.5 +0.4 +0.5 +0.7 +1.5 +0.5 +0.7 +0.7 +0.5 +0.3 K7EG +1.3 +0.6 +0.8 +1.1 +1.1 +0.6 +0.7 +0.8 +0.6 +0.3 K7MJG -8.9 -10.9 -10.0 -9.8 -9.5 -10.2 -9.4 -8.8 -0.3 -0.3 K9IMM -0.0 -0.0 +0.0 +0.0 +0.0 +0.0 +0.1 +0.1 +0.1 -0.0 K9LC -0.3 -0.2 -0.2 -0.5 -0.5 -0.3 -0.4 -0.4 -0.3 -0.3 K9TM-4 +1.1 +0.7 +0.7 +1.3 +1.3 +0.8 +0.8 +1.0 +0.8 +0.7 KB9AMG +2.3 +3.6 KC0VKN -0.8 -1.3 -0.8 -1.5 -1.6 -1.8 -0.6 -0.9 -0.8 -1.2 KC2IEB -9.1 KC4YVA +5.1 +4.1 +3.8 +5.3 +5.3 +4.3 +4.7 +5.0 +4.9 +3.9 KD2OGR -0.0 -0.2 +0.0 +0.1 +0.0 -0.1 -0.1 -0.0 +0.0 +0.1 KD7YZ -0.1 +0.1 -0.0 +0.5 +0.9 +0.7 +0.6 +0.3 +0.2 +0.3 KH6LC +0.2 +0.0 +0.0 +0.2 +0.1 -0.2 +0.8 +0.2 +0.4 -1.0 KI4PAD -10.6 -11.7 -12.6 -10.4 -10.9 KM3T -0.0 -0.2 -0.0 -0.0 +0.0 +0.0 -0.0 -0.1 +0.1 -0.1 KM3T-1 +0.2 +0.5 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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 AC0C-1 DF7GB K3PA-1 KM3T KM3T-1 OE9GHV Last updated 2021-12-02 00:15:34 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.