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.
264972 RBN spots between 2022-05-17 00:00 and 23:59 UTC. 66963 spots (25.3%) were from reference skimmers (*). Average spot flow was 184 per minute from 185 active CW skimmers. 128886 spots from 181 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 +0.6 84 1.000000594 3D2AG +0.5 44 1.000000486 3V8SS -2.3 1204 0.999997701 5W1SA +0.5 55 1.000000454 9A1CIG +8.3 475 1.000008295 9M2CNC +0.2 192 1.000000165 AA4VV* +0.1 1067 1.000000053 AC0C-1 -0.3 309 0.999999714 BA6KC +0.9 22 1.000000865 BD4QJP +1.5 66 1.000001477 BG4GOV -1.0 29 0.999998989 BG8DIV -4.9 72 0.999995114 BG8PA -0.1 74 0.999999904 BH4DEG +4.3 13 1.000004293 BH4RRG0 +0.0 6 1.000000000 CX6VM +0.6 80 1.000000615 DD5XX +0.4 869 1.000000442 DE1LON +0.8 1773 1.000000803 DF2CK +0.9 2253 1.000000897 DF4XX +0.1 941 1.000000070 DF7GB* +0.0 1573 1.000000042 DG6FL -1.6 18 0.999998416 DJ2BC -0.6 742 0.999999382 DK0TE +3.0 1382 1.000003006 DK9IP* +0.0 1253 1.000000008 DL0LA +0.2 1141 1.000000193 DL0PF +4.9 831 1.000004877 DL1AXX +0.2 69 1.000000206 DL1HWS +0.2 2000 1.000000242 DL8LAS +1.2 2021 1.000001222 DL9GTB -0.4 1777 0.999999555 DM5GG* +0.1 2297 1.000000112 DM6EE -1.1 1853 0.999998893 EA1URA +0.5 1342 1.000000477 EA2NN -0.2 152 0.999999812 EA5WU +0.3 1414 1.000000303 EA8BFK +0.4 1832 1.000000436 ES2RR +0.2 2053 1.000000193 ES5PC* -0.1 755 0.999999896 EY8ZE +0.5 618 1.000000495 F4VSQ +5.7 214 1.000005716 F6IIT -0.2 1664 0.999999787 F8DGY +1.1 372 1.000001110 G0KTN* +0.0 1485 1.000000035 G1VWC +0.2 68 1.000000209 G3XBI +0.2 181 1.000000183 G4AON +1.2 177 1.000001208 G4KZD +0.8 588 1.000000823 G4MKR +1.3 16 1.000001338 G4ZFE* -0.0 1693 0.999999993 GI4DOH +0.4 640 1.000000391 GM6DX +0.7 227 1.000000701 HA1VHF* +0.0 1472 1.000000009 HA5PP -0.6 6 0.999999405 HA6PX +0.1 690 1.000000140 HA8TKS* +0.1 1082 1.000000120 HB9BXE +1.0 1201 1.000001036 HB9DCO* -0.1 1801 0.999999884 HG8A +4.4 1854 1.000004405 HS/F8UKP -0.5 72 0.999999528 HS8KVH +5.5 207 1.000005498 IK3STG +7.1 311 1.000007088 IK4VET +0.4 2363 1.000000371 IZ2CPS +0.4 1058 1.000000356 JA4ZRK +0.0 13 1.000000000 JH7CSU1 +4.5 97 1.000004543 JI1HFJ -3.0 50 0.999996987 JJ2VLY +0.1 181 1.000000059 JN1ILK -0.2 347 0.999999758 JQ1BVI +0.1 133 1.000000107 K2PO/7 +0.6 117 1.000000588 K3PA-1 +0.4 858 1.000000422 K4PP* +0.0 367 1.000000020 K5TR +1.5 712 1.000001497 K6FOD +1.0 50 1.000000995 K7EG +0.6 241 1.000000565 K7EK -10.3 228 0.999989739 K7MJG -14.6 137 0.999985435 K9IMM -0.2 401 0.999999827 K9LC* -0.0 788 0.999999968 K9TM-4 +1.2 1010 1.000001177 KC0VKN -1.0 186 0.999999042 KC4YVA +4.7 366 1.000004700 KD2OGR* -0.1 636 0.999999853 KG7V -0.5 185 0.999999536 KH6LC +0.1 99 1.000000144 KM3T* +0.1 1573 1.000000057 KM3T-1 +0.3 278 1.000000307 KM3T-2 +1.2 654 1.000001198 KO7SS +0.8 992 1.000000764 KO7SS-7 +0.2 565 1.000000200 KP2RUM* -0.1 1180 0.999999949 LA6TPA +0.4 686 1.000000386 LZ3CB* -0.0 845 0.999999976 LZ4AE +2.3 863 1.000002315 LZ4UX* -0.0 782 0.999999992 LZ5DB +0.5 403 1.000000504 LZ7AA +0.5 1049 1.000000493 MM0ZBH* -0.1 1884 0.999999853 N4ZR +0.2 1350 1.000000227 N6TV +0.5 341 1.000000534 N7TUG +5.5 93 1.000005539 NA0B +0.1 219 1.000000065 NC7J +0.8 489 1.000000765 NN3RP +0.6 451 1.000000638 NR4U +0.0 5 1.000000000 NT6Q +0.9 149 1.000000930 NU6XB -0.5 133 0.999999518 OE8TED +1.1 975 1.000001083 OE9GHV* -0.0 2235 0.999999954 OG66X -0.8 243 0.999999241 OH4KA -0.5 924 0.999999542 OH6BG +2.5 2476 1.000002482 OH8KA -3.7 1559 0.999996269 OK1FCJ +0.2 1953 1.000000198 OK1HRA -6.2 532 0.999993769 OK2ZAW +1.5 774 1.000001510 ON6ZQ -0.3 335 0.999999745 PA0MBO -0.3 375 0.999999746 PA8MM -5.9 149 0.999994068 PS8CW +0.1 105 1.000000090 R9IR -0.1 110 0.999999921 RK3TD* -0.1 1300 0.999999931 RN4WA -0.4 1387 0.999999647 RU9CZD +0.5 1390 1.000000492 S53WW -1.8 1959 0.999998237 SE5E* +0.1 2193 1.000000086 SM0TCZ +0.7 20 1.000000713 SM6FMB +0.2 1195 1.000000217 SM7IUN* -0.1 1467 0.999999938 SP8R -6.7 571 0.999993301 SV1CDN +0.5 37 1.000000514 SV8RV +0.3 694 1.000000342 SZ1A +1.4 806 1.000001407 TF3Y +1.0 1434 1.000000952 TF4X -1.5 1702 0.999998544 UA0S* -0.0 496 0.999999976 UA3REO +0.3 268 1.000000287 UA4M +4.6 69 1.000004620 UP2L -5.2 396 0.999994841 V51YJ +1.4 62 1.000001381 VE2WU +0.2 493 1.000000173 VE6AO -0.4 124 0.999999633 VE6JY +0.9 987 1.000000937 VE6WZ +2.6 527 1.000002552 VE7CC -0.2 378 0.999999800 VK2GEL +2.7 67 1.000002720 VK3RASA -0.0 176 0.999999975 VK4CT -0.3 415 0.999999662 VK6ANC -1.5 67 0.999998529 VU2PTT +6.6 128 1.000006572 W1NT-2 -1.3 1505 0.999998745 W1NT-6* -0.1 1926 0.999999894 W2LB +0.8 167 1.000000764 W2MV +0.4 160 1.000000401 W2NAF +1.2 1392 1.000001239 W3LPL +1.1 1253 1.000001134 W3OA* +0.0 402 1.000000036 W3RGA* +0.2 837 1.000000204 W3RGA-2* +0.1 569 1.000000135 W3UA* -0.1 275 0.999999930 W4AX +3.5 230 1.000003468 W4KAZ -0.5 1208 0.999999493 W6BB -0.7 176 0.999999326 W6YX +0.7 609 1.000000650 W7HR +0.5 260 1.000000542 W8WTS -0.7 716 0.999999275 W8WWV +0.8 1024 1.000000820 W9XG +1.8 569 1.000001805 WA2ZYU +3.6 12 1.000003569 WA7AI +0.3 322 1.000000289 WA7LNW +0.6 531 1.000000610 WB6BEE* +0.1 715 1.000000061 WC2L +0.0 86 1.000000000 WE9V* -0.2 1038 0.999999767 WF7U +1.1 352 1.000001061 WS3W +1.1 1075 1.000001119 WZ7I* +0.0 829 1.000000040 ZL2HAM -0.7 414 0.999999348 ZL2KS -4.8 150 0.999995179 ZL4YL +1.7 145 1.000001653 Last updated 2022-05-18 00:15:23 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 0517 0516 0515 0514 0513 0512 0511 0510 0509 0508 --------------------------------------------------------------------- 3B8CW +0.6 +0.0 +0.2 +0.4 +0.5 +0.3 -0.0 +0.3 +0.0 +0.4 3D2AG +0.5 +0.0 +1.8 +0.5 +0.6 +0.0 +0.4 -0.2 -0.1 3V8SS -2.3 -2.4 -2.6 -2.3 -2.1 -2.6 -2.5 -2.4 -2.5 -2.5 5W1SA +0.5 +0.7 +0.3 +0.8 +0.8 +0.7 +0.7 9A1CIG +8.3 +8.8 +9.8 +6.7 +6.0 +7.4 +7.7 +11.6 +9.4 +5.7 9M2CNC +0.2 -0.2 +0.9 +0.6 +1.0 +0.6 +0.2 +0.3 AA4VV +0.1 -0.1 -0.1 -0.2 -0.0 -0.0 -0.0 +0.0 -0.0 -0.0 AC0C-1 -0.3 +0.1 -0.3 +0.1 -0.1 -0.1 +0.0 +0.0 -0.1 -0.0 AC0C-2 +0.2 +0.0 +0.1 +0.0 +0.1 -0.1 BA6KC +0.9 +1.1 +0.7 +1.0 +0.7 +0.4 +0.7 +0.0 BD4QJP +1.5 +2.0 +2.1 +0.9 +1.9 +1.3 +2.1 BD7JNA +0.7 +0.0 BG4GOV -1.0 +0.2 -0.0 -0.3 +0.0 -0.8 -0.3 -0.9 -1.4 -0.1 BG8DIV -4.9 -5.1 -4.1 -4.6 -4.3 -3.8 -4.8 -4.4 -4.3 -3.5 BG8FZU +4.5 +3.1 +3.5 +4.7 +5.2 +5.0 +4.2 BG8PA -0.1 -0.1 +2.1 +11.3 +11.0 +11.5 +11.4 +11.0 BH3BBJ +2.9 -3.1 -1.2 -0.5 -3.9 BH4DEG2 +2.1 +2.1 +1.9 +1.2 +1.1 BH4DEG +4.3 +4.0 +4.8 +3.3 +4.0 +4.1 +3.1 +3.8 +3.5 +4.5 BH4RRG0 +0.0 +0.0 +0.1 +0.8 +0.4 +0.6 -0.4 -0.3 BH4XDZ +1.6 +1.4 +0.6 +0.3 +0.8 +0.6 +1.0 +1.7 CT7ANO +0.1 CX6VM +0.6 +0.5 +0.1 +0.8 +0.8 +1.1 +0.9 +1.2 +1.2 +1.3 DD5XX +0.4 +0.3 +0.4 +0.5 +0.4 +0.4 +0.4 +0.3 +0.3 +0.3 DE1LON +0.8 +0.5 +0.6 +0.7 +0.4 +0.5 +0.8 +0.5 +0.3 +0.4 DF2CK +0.9 +0.7 +0.8 +1.0 +0.9 +0.8 +0.5 +0.5 +0.4 -0.7 DF2CK/1 -0.0 -0.1 +0.2 DF4XX +0.1 +0.2 +0.2 +0.3 +0.0 +0.2 +0.2 +0.1 +0.2 +0.0 DF7GB +0.0 +0.0 -0.0 -0.0 -0.0 -0.1 -0.0 -0.0 -0.0 -0.1 DG6FL -1.6 -1.1 -0.6 -0.6 -2.1 -3.4 -0.4 +0.0 -0.9 -0.8 DJ2BC -0.6 -0.7 -0.7 -0.6 -0.5 -0.7 -0.4 -0.1 DK0TE +3.0 +2.8 +3.3 +2.9 +2.5 +2.8 +3.0 +2.2 +2.6 +3.0 DK3UA -0.3 -0.4 -0.6 DK9IP +0.0 -0.1 -0.1 +0.0 +0.0 -0.0 +0.1 -0.1 -0.1 -0.1 DL0LA +0.2 +0.2 +0.3 +0.3 +0.2 +0.2 +0.2 -0.0 +0.2 DL0PF +4.9 +4.2 +4.6 +4.6 +4.5 +4.6 +4.5 +4.2 +3.7 +4.0 DL1AXX +0.2 +0.5 +0.4 +0.1 +0.2 +0.0 +0.3 +0.1 +0.1 DL1HWS +0.2 +0.2 +0.2 +0.1 +0.2 +0.2 +0.2 +0.1 +0.1 +0.1 DL5RMH +0.0 DL8LAS +1.2 +1.1 +1.4 +1.3 +0.9 +1.1 +1.4 +1.2 +1.2 +1.3 DL8TG -1.1 -1.0 -1.0 -0.9 -1.0 -1.1 DL9GTB -0.4 -0.5 -0.3 -0.8 -0.4 +0.2 +0.2 +0.1 +0.0 -0.3 DM5GG +0.1 +0.0 +0.1 +0.1 -0.0 +0.1 +0.1 +0.0 -0.0 +0.1 DM6EE -1.1 -1.5 -1.7 -0.2 -0.6 -1.1 -1.0 -1.1 -1.7 -1.4 DO4DXA -0.1 -0.1 -0.1 +0.1 +0.0 DU3TW -11.6 +0.6 -1.4 -0.8 -1.1 -1.9 +0.0 EA1URA +0.5 +0.3 +0.3 +0.3 +0.1 +0.1 +0.2 +0.3 +0.4 +0.2 EA2NN -0.2 -0.1 +0.2 +0.1 +0.2 EA5WU +0.3 +0.1 +0.1 +0.3 +0.0 +0.2 -0.0 +0.0 +0.1 +0.1 EA8BFK +0.4 +0.4 +0.5 +0.4 +0.4 +0.4 +0.5 +0.3 +0.3 +0.4 ES2RR +0.2 +0.2 -0.0 +0.4 +0.4 +0.1 +1.0 +0.2 +0.4 +0.4 ES5PC -0.1 -0.1 -0.1 -0.1 -0.1 -0.0 +0.1 -0.1 -0.1 -0.0 ET3AA +0.8 +0.4 +0.9 +0.9 +0.7 EY8ZE +0.5 +0.4 +0.7 +0.6 +0.5 +0.5 +0.6 +0.5 +0.4 +0.5 F4VSQ +5.7 +5.4 +4.3 +4.2 +5.0 +4.5 +4.8 +4.5 F6IIT -0.2 -0.3 -0.4 -0.5 -0.5 -0.5 -0.4 -0.4 -0.7 -0.7 F8DGY +1.1 +0.3 +0.6 G0KTN +0.0 -0.1 +0.1 +0.3 +0.1 +0.1 +0.0 +0.2 +0.1 +0.1 G0TMX -0.0 G0TTV +0.9 G1VWC +0.2 +0.2 -0.1 -0.3 +0.0 -0.1 -0.1 G3XBI +0.2 +0.0 +0.0 +0.2 +0.0 +0.1 G4AON +1.2 +0.8 +1.2 +0.8 +1.4 +1.6 +1.2 G4IRN +0.0 G4KZD +0.8 +0.5 +0.4 +0.8 +0.6 -0.1 +0.2 +0.4 -0.0 +0.1 G4MKR +1.3 +0.4 G4ZFE -0.0 -0.0 -0.1 +0.0 +0.0 -0.0 -0.0 +0.1 +0.0 -0.0 GI4DOH +0.4 +0.0 +0.6 +0.6 +0.2 +0.5 +0.5 +0.5 +0.3 +0.4 GM6DX +0.7 +0.5 +0.6 +0.2 +0.7 +0.5 +0.6 +0.6 HA1VHF +0.0 +0.0 -0.0 -0.1 +0.0 +0.0 -0.0 -0.2 -0.2 -0.4 HA5PP -0.6 +2.3 -1.7 +3.6 HA5PP-2 +0.5 HA6PX +0.1 +0.1 +0.2 +0.2 +0.4 +0.4 +0.2 -0.4 -0.5 -0.7 HA7GN -0.5 -0.5 +2.8 +1.3 +1.2 -10.6 -13.4 -13.1 HA8TKS +0.1 +0.1 +0.1 +0.0 +0.2 +0.2 +0.1 +0.1 +0.1 +0.2 HB9BXE +1.0 +1.1 +1.2 +1.5 +2.5 +10.7 +9.4 +9.4 +9.0 HB9CAT +4.8 +4.2 +4.3 +4.2 HB9DCO -0.1 -0.2 +0.0 -0.2 -0.2 -0.2 -0.1 -0.1 -0.1 -0.1 HG8A +4.4 +4.4 +4.3 +4.3 +4.5 +4.7 +4.2 +3.9 +3.7 +3.7 HS8KVH +5.5 +5.5 +4.7 +4.9 +1.5 +2.1 +2.0 +0.6 +0.2 HS/F8UKP -0.5 -0.1 -0.6 -0.4 -0.2 -0.6 -0.3 -0.4 -0.4 -0.4 IK3STG +7.1 +7.2 +6.6 +7.0 +7.5 +6.9 +7.0 +6.6 +6.8 +6.5 IK4VET +0.4 +0.4 +0.6 +0.4 +0.4 +0.4 +0.4 +0.8 IQ8SN +1.1 +1.0 IZ2CPS +0.4 +0.2 +0.3 +0.3 +0.5 +0.4 +0.3 +0.2 +0.1 +0.1 JA4ZRK +0.0 -0.3 +0.2 -0.2 +0.0 +0.5 +0.0 +2.8 +0.7 -0.2 JH7CSU1 +4.5 +5.5 +4.7 +4.4 +4.5 +5.3 +5.1 +4.2 +5.2 +5.0 JI1HFJ -3.0 +2.9 -2.4 -5.5 -5.7 -4.1 -4.0 -5.3 -2.8 JJ2VLY +0.1 -0.1 +1.4 +0.9 +0.2 -0.2 +0.5 +0.2 +0.1 +0.3 JN1ILK -0.2 -0.0 +0.7 +1.1 +1.0 +0.7 +0.9 +0.7 +0.8 +1.2 JQ1BVI +0.1 -0.0 +0.1 -0.2 -0.3 -0.5 +0.2 -0.1 +0.6 +0.5 K2PO/7 +0.6 +0.5 +0.5 +0.6 +0.6 +0.3 +0.8 +0.3 +0.3 +1.0 K3PA -0.0 K3PA-1 +0.4 -0.1 +0.1 +0.3 +0.0 +0.0 +0.0 -0.0 -0.0 -0.0 K4PP +0.0 +0.2 +0.4 +0.2 +0.3 +0.2 +0.2 +0.1 +0.1 -0.1 K5TR +1.5 +1.4 +1.4 +1.4 +0.7 +0.2 +0.2 +0.4 +1.1 +1.5 K6FOD +1.0 +0.4 +0.3 +0.0 +0.3 -0.2 +0.1 +0.4 +0.0 +0.2 K7EG +0.6 +0.7 +0.6 +0.7 +0.6 +0.8 +1.1 +0.7 +0.8 +0.9 K7EK -10.3 -9.9 -10.4 -8.4 -9.3 -10.7 -9.7 -9.8 -9.3 -9.2 K7MJG -14.6 -15.0 -14.6 -15.1 +5.9 -18.1 -17.2 -19.8 -18.0 -17.5 K9IMM -0.2 +0.1 +0.0 -0.0 +0.0 +0.0 +0.1 +0.1 +0.1 +0.1 K9LC -0.0 +0.0 -0.0 -0.1 -0.0 +0.0 +0.0 +0.1 -0.1 -0.3 K9TM-4 +1.2 +0.9 +1.0 +1.1 +1.0 +0.7 +1.1 +0.9 +0.9 +1.1 KC0VKN -1.0 -0.7 -1.0 -1.5 -1.2 -1.0 -1.1 -1.0 -0.7 -1.1 KC4YVA +4.7 +5.4 +4.2 +5.1 +5.2 +5.7 +5.2 +5.1 +4.8 +5.7 KD2OGR -0.1 -0.2 -0.1 +0.0 -0.2 -0.2 -0.0 -0.0 -0.0 +0.0 KG7V -0.5 -1.0 -0.9 -0.9 -1.0 -1.4 -1.1 -0.8 -1.2 -1.3 KH6LC +0.1 +0.3 -0.1 +0.1 +0.1 -0.1 -0.0 +0.2 +0.0 +0.1 KM3T +0.1 -0.1 -0.1 -0.1 -0.0 +0.1 -0.0 +0.0 -0.0 -0.1 KM3T-1 +0.3 +0.0 -0.5 +0.0 +0.0 -0.0 -0.0 +0.2 -0.3 -0.2 KM3T-2 +1.2 +1.0 +0.8 +1.3 +0.6 +0.6 +0.4 +0.4 +0.2 +0.1 KO7SS +0.8 +0.5 +0.5 +0.1 -0.1 -0.2 -0.3 -0.2 -0.2 +0.2 KO7SS-7 +0.2 +0.2 +0.2 +0.2 +0.1 +0.1 +0.1 +0.3 +0.2 +0.6 KP2RUM -0.1 -0.1 -0.0 +0.1 -0.1 +0.0 +0.1 +0.1 -0.0 -0.0 LA6TPA +0.4 +0.1 +0.0 +0.2 +0.4 +0.7 +1.4 +3.1 +1.6 +1.1 LZ3CB -0.0 -0.1 -0.1 +0.0 -0.1 +0.0 +0.1 -0.1 -0.1 -0.0 LZ4AE +2.3 +2.6 +3.0 +2.5 +1.8 +1.9 +1.9 +2.2 LZ4UX -0.0 -0.1 -0.2 -0.1 -0.1 +0.0 +0.0 +0.0 -0.1 -0.0 LZ5DB +0.5 +0.4 +0.0 LZ7AA +0.5 +0.4 +0.5 +0.5 +0.6 +0.5 +0.6 +0.5 +0.3 +0.5 M7RMZ +0.4 +0.4 +0.0 MM0ZBH -0.1 -0.5 +1.8 +2.2 +1.1 +0.9 +1.9 +1.1 +1.1 -2.2 N4ZR +0.2 +0.3 +0.3 +0.3 +0.2 +0.3 +0.2 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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 DF7GB KM3T LZ3CB OE9GHV WB6BEE Last updated 2022-05-18 00:15:28 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.