Skimmer frequency accuracy
To be a good RBN citizen a skimmer should have a frequency accuracy of 2ppm or better.
VERY IMPORTANT: 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 the different bands, the deviation number may thus not represent the actual deviation for a particular band. It is a good practice to run a separate instance of RBN Aggregator with a unique SSID for each hardware, (SM7IUN-1, SM7IUN-2, etc.)
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 criteria 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
282441 RBN spots between 2024-09-19 00:00 and 23:59 UTC. 87365 spots (30.9%) were from reference skimmers (*). Average spot flow was 196 per minute from 177 active CW skimmers. 144689 spots from 175 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 1815 0.999999974 3B8CW +0.0 10 1.000000000 5W1SA +1.4 20 1.000001425 5Z4GO -1.0 7 0.999998983 9M2CNC +0.0 33 1.000000000 AA0O +0.0 40 1.000000000 AC0C-1* -0.1 868 0.999999897 BA6KC +0.0 169 1.000000028 BD4QJP +0.0 13 1.000000000 BD7JNA +0.0 23 1.000000000 BG0AJO +0.1 37 1.000000149 BG2TFW -6.7 5 0.999993344 BG4GOV +0.0 17 1.000000000 BH4RRG +0.0 24 1.000000000 BH4XDZ +0.0 20 1.000000000 BI4MPH-1 +0.0 20 1.000000000 CT7ANO +7.7 313 1.000007675 DC8YZ* -0.0 2283 0.999999975 DE1LON +0.8 1707 1.000000830 DF2CK +0.9 3353 1.000000910 DF7GB* -0.0 1812 0.999999994 DK0TE +1.2 1652 1.000001214 DK1MAX -0.1 61 0.999999941 DK9IP* -0.1 1144 0.999999942 DK9IP-1* +0.0 1597 1.000000043 DL0LA* -0.2 1339 0.999999802 DL0PF +5.1 3374 1.000005062 DL1HWS* +0.0 1909 1.000000010 DL1HWS-3 +0.2 987 1.000000213 DL5RCN +11.5 866 1.000011536 DL8LAS -1.0 2672 0.999999013 DL8TG* +0.0 1798 1.000000043 DM5GG +0.4 2811 1.000000418 DM6EE* +0.0 2039 1.000000030 E28AC +1.1 34 1.000001118 EA1RX -3.8 99 0.999996248 EA1URA +0.3 1359 1.000000279 EA2CW -0.3 747 0.999999701 EA2RCF-4 -0.5 1004 0.999999508 EA5RQ +0.3 630 1.000000275 EA5RQ/A +0.0 21 1.000000000 ES2RR* -0.0 2052 0.999999958 F4GOU +3.0 1609 1.000003049 F4VVG* -0.0 512 0.999999978 F6KGL* +0.2 920 1.000000160 F8DGY +0.3 1143 1.000000322 G0KTN +0.2 1740 1.000000181 G4AON +1.1 256 1.000001110 G4FRE +14.5 278 1.000014545 G4IRN +0.3 2381 1.000000343 G4MKR +0.2 30 1.000000238 G4YBU -0.4 1135 0.999999628 G4ZFE +0.5 1954 1.000000504 GI4DOH +0.4 841 1.000000415 HA1VHF -0.5 1691 0.999999495 HA6PX* -0.0 1782 0.999999976 HA8TKS +0.1 1337 1.000000075 HB9DCO -0.2 1319 0.999999754 HG0Y +7.6 638 1.000007574 HG8A -0.9 1976 0.999999079 IK3STG +26.0 58 1.000025978 IK4VET +1.8 2279 1.000001760 JH7CSU1 -0.4 36 0.999999604 JI1HFJ -2.9 15 0.999997147 JJ2VLY +1.7 38 1.000001667 JN1ILK +0.2 197 1.000000183 K1HTV +14.0 1191 1.000014040 K3PA-1 -0.0 541 0.999999987 K3PA-2 +0.0 47 1.000000000 K4PP* +0.0 539 1.000000016 K5TR +0.2 372 1.000000240 K6FOD +0.1 408 1.000000136 K7CO -0.5 504 0.999999486 K7EK +0.3 69 1.000000310 K7MJG +0.1 173 1.000000124 K9IMM +9.4 106 1.000009381 K9LC +0.3 796 1.000000303 KA7OEI +0.1 175 1.000000093 KD2OGR +0.2 449 1.000000183 KH6LC +0.2 154 1.000000185 KM3T* -0.1 707 0.999999862 KM3T-2 +0.7 1029 1.000000698 KM3T-3 +0.1 1258 1.000000088 KO7SS +0.4 495 1.000000378 KP3CW +0.3 959 1.000000252 LA6TPA -0.6 696 0.999999416 LA7GIA* -0.1 504 0.999999926 LB9KJ -0.5 311 0.999999462 LU8XW -0.3 18 0.999999736 LZ3CB* -0.0 1107 0.999999995 LZ4AE* +0.1 1633 1.000000057 LZ4UX* -0.0 1141 0.999999966 LZ5DI -0.5 1997 0.999999506 MM0ZBH* +0.1 1983 1.000000060 MM3NDH +0.0 2374 1.000000025 MM3NDH-2* -0.0 1468 0.999999969 MM3NDH-3 +0.2 531 1.000000215 MW0MUT +0.2 1908 1.000000162 N6TV +0.8 466 1.000000835 N7TUG +16.3 165 1.000016275 N9CO* +0.1 682 1.000000098 ND7K -0.5 520 0.999999465 NG7M -0.4 345 0.999999569 NN3RP +0.0 29 1.000000000 NT6Q +0.3 674 1.000000311 NU4F +0.0 9 1.000000000 OE6TZE* +0.1 1332 1.000000089 OE9GHV* -0.1 1612 0.999999885 OG66X +0.6 11 1.000000649 OH4KA* +0.1 1920 1.000000128 OH6BG* -0.2 1852 0.999999827 OH8KA -4.9 270 0.999995083 OK1FCJ* +0.1 1270 1.000000076 OK1HRA -3.8 2020 0.999996194 OK4QRO +1.8 1588 1.000001782 ON6ZQ +0.2 1340 1.000000165 OZ1AAB* -0.0 577 0.999999988 OZ1BZS +0.4 315 1.000000430 OZ4ADX* -0.1 568 0.999999950 PA0MBO +0.2 389 1.000000181 PA8MM +0.2 1275 1.000000169 PE5TT +0.5 1354 1.000000482 R6YY +0.2 622 1.000000157 R9IR -0.2 596 0.999999846 RK3TD +0.6 1597 1.000000583 RN4WA +0.4 774 1.000000356 RU9CZD -4.6 908 0.999995449 S50U* +0.0 553 1.000000046 S53A +1.0 2469 1.000001034 S53WW* +0.1 1818 1.000000127 SM1HEV -0.9 544 0.999999111 SM7IUN* +0.0 1971 1.000000019 SQ5J +8.8 1410 1.000008849 SQ5OUO +5.0 992 1.000004986 SV1CDN +1.7 223 1.000001725 SV1DPJ +0.4 527 1.000000439 TF3Y +1.7 701 1.000001714 TI7W* -0.1 894 0.999999896 UA0S -0.8 284 0.999999166 UW5EMC +2.1 64 1.000002116 V51YJ +3.0 34 1.000002987 VE6AO -0.9 171 0.999999102 VE6JY +2.9 590 1.000002934 VE6WZ -14.3 240 0.999985728 VE7CC +1.0 245 1.000001008 VK2EBN -1.2 6 0.999998812 VK2RH +0.2 23 1.000000241 VK3RASA -1.0 73 0.999998970 VK6ANC -2.5 72 0.999997458 VR2FUN-77 +0.0 7 1.000000000 VU2PTT +5.6 89 1.000005646 W1NT-2 +0.7 911 1.000000670 W1NT-6 +0.4 1160 1.000000434 W2MV +0.4 182 1.000000391 W2NAF +1.5 626 1.000001527 W3LPL -2.5 610 0.999997486 W3OA* -0.0 1131 0.999999989 W4AX +3.4 63 1.000003362 W4KAZ* -0.1 519 0.999999945 W6YX +0.3 752 1.000000340 W8WWV -1.8 664 0.999998235 WA7LNW* +0.3 872 1.000000286 WB6BEE -0.2 761 0.999999781 WC2L* +0.0 859 1.000000019 WC8GOP +11.0 75 1.000010975 WE9V +0.6 780 1.000000584 WS2C +3.4 861 1.000003432 WS3W +1.0 296 1.000001000 WV4P +0.1 1078 1.000000108 YO2MAX* -0.1 1981 0.999999926 YO4RDW -7.8 213 0.999992191 YO5LD -1.0 14 0.999999039 ZL3X -0.6 317 0.999999434 ZL4YL +1.3 258 1.000001278 ZS1NN -3.8 28 0.999996218 Last updated 2024-09-20 00:15:26 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 0919 0918 0917 0916 0915 0914 0913 0912 0911 0910 --------------------------------------------------------------------- 2E0INH -0.0 -0.0 -0.0 +0.1 -0.0 -0.1 -0.0 -0.1 +0.0 -0.0 3B8CW +0.0 +1.2 -1.0 -0.2 +0.0 +0.0 +0.0 +0.1 +0.4 5W1SA +1.4 +2.0 +1.6 +2.6 5Z4GO -1.0 +0.0 +0.0 -0.0 +0.0 +0.4 +0.4 -0.7 +1.0 +0.6 9M2CNC +0.0 +0.2 +0.3 -0.0 +0.1 +0.5 +0.3 +0.5 +0.8 +0.4 AA0O +0.0 +0.2 +0.2 +0.3 +0.2 +0.2 +0.2 +0.1 +0.3 +0.2 AC0C-1 -0.1 -0.1 -0.1 -0.1 -0.0 -0.1 -0.1 -0.1 -0.0 -0.2 BA6KC +0.0 +0.0 +0.0 +0.0 -0.1 -0.0 -0.4 +0.2 +0.1 -0.0 BD4QJP +0.0 -0.2 +0.0 -0.1 +0.0 +0.5 +0.0 +0.8 +0.1 +0.1 BD7JNA +0.0 -0.2 +0.0 -0.2 +0.3 +0.4 -0.9 BG0AJO +0.1 +0.0 +0.0 +0.0 -0.2 -0.1 +0.3 +0.0 +0.1 +0.6 BG2TFW -6.7 -7.6 -6.2 -7.1 -6.6 -5.5 -8.1 -6.5 BG4GOV +0.0 +0.6 +0.0 +0.0 -0.3 +0.0 +0.5 +0.0 BH4RRG +0.0 +0.1 +0.7 -0.2 +0.0 +0.1 -0.6 +0.4 +0.1 -0.3 BH4RXP +0.0 -0.0 +0.3 -0.1 -0.2 BH4XDZ +0.0 -0.0 +0.0 -0.1 +0.0 +0.1 +0.0 +0.5 +0.2 +0.2 BI4MPH-1 +0.0 +0.1 -0.6 +0.0 -1.3 +0.0 +0.0 +0.7 +0.1 +0.1 CT7ANO +7.7 +7.5 +8.0 +7.7 CW1SKIM -0.7 DC8YZ -0.0 +0.1 +0.1 -0.0 -0.0 +0.0 +0.0 +0.1 +0.1 +0.0 DE1LON +0.8 +1.0 +0.9 +0.9 +0.4 +0.8 +0.5 +0.7 +1.0 +0.9 DF2CK +0.9 -0.1 +0.1 -0.1 -0.1 +0.0 -0.4 +0.0 +0.0 +0.2 DF2CK-1 +3.3 +5.6 -0.7 DF7GB -0.0 +0.0 +0.1 -0.1 +0.0 -0.0 -0.1 +0.0 -0.1 -0.0 DG6FL +0.0 +0.0 DJ9IE-10 -0.1 DJ9IE-6 +0.3 +0.0 +0.1 DJ9IE-7 -0.3 +0.0 +0.1 DJ9IE-8 +0.1 -0.1 +0.2 +0.0 +0.1 +0.0 DJ9IE-9 +0.2 +0.1 DK0TE +1.2 +0.9 +0.7 +0.8 +0.7 +1.0 +1.0 +1.0 +0.7 +0.4 DK1MAX -0.1 +0.1 -0.2 -0.0 -0.1 +0.0 +0.0 DK8NE +1.7 DK9IP -0.1 +0.1 +0.2 +0.0 -0.0 -0.0 -0.1 +0.0 +0.1 +0.0 DK9IP-1 +0.0 +0.0 +0.1 +0.2 +0.1 +0.1 +0.0 +0.1 +0.2 +0.2 DL0LA -0.2 -0.2 -0.3 -0.3 -0.1 -0.1 -0.1 -0.0 +0.0 +0.1 DL0PF +5.1 +5.0 -0.5 -0.6 -0.4 -0.4 -0.1 DL1HWS +0.0 +0.1 +0.1 +0.0 +0.0 +0.1 +0.1 +0.1 +0.1 +0.1 DL1HWS-2 +0.5 +0.5 +0.5 +0.3 DL1HWS-3 +0.2 +0.7 +0.8 +0.5 +0.4 +0.7 DL5RCN +11.5 -0.0 +1.2 +12.6 DL8LAS -1.0 -0.6 +0.2 +0.2 +0.1 +0.2 +0.1 +0.2 +0.3 +0.3 DL8TG +0.0 +0.0 +0.0 -0.1 -0.1 -0.1 -0.1 +0.6 -0.0 -0.1 DM5GG +0.4 +0.5 +0.3 +0.3 +0.1 +0.2 +0.3 +0.3 +0.6 +0.6 DM6EE +0.0 +0.0 -0.0 -0.1 -0.0 -0.0 -0.0 +0.0 -0.0 -0.1 E28AC +1.1 +0.0 +1.6 +2.2 +2.7 +1.0 EA1RX -3.8 -1.8 -3.2 -3.8 -4.3 -3.0 -1.9 -4.6 EA1URA +0.3 +0.4 +0.3 +0.2 +0.1 -0.0 +0.1 +0.1 +0.2 +0.3 EA2CW -0.3 -0.4 -0.2 -0.1 EA2RCF-4 -0.5 -0.6 -0.5 -0.9 -0.5 -0.7 -0.6 -0.4 -0.4 -0.4 EA5RQ +0.3 +0.2 +0.3 +0.4 +0.2 +0.3 +0.2 +0.4 +0.4 +0.5 EA5RQ/A +0.0 -0.2 +0.0 +0.0 +0.1 +0.0 EA5WU -0.0 -0.1 -0.1 -0.1 ES2RR -0.0 -0.0 -0.1 -0.1 -0.1 -0.0 -0.0 -0.0 -0.1 -0.1 ET3AA -13.1 -13.2 -12.9 F4GOU +3.0 +2.7 +2.3 +2.8 +2.3 +3.1 +2.8 +2.6 +2.9 +2.8 F4VVG -0.0 +0.1 +0.3 +1.4 +0.5 +0.8 F6KGL +0.2 +0.1 +0.1 +0.1 +0.2 +0.2 +0.1 +0.2 +0.3 +0.2 F8DGY +0.3 +0.3 +0.3 +0.2 +0.1 +0.1 +0.1 -0.2 -0.2 -0.0 G0KTN +0.2 +0.3 +0.2 +0.2 +0.1 +0.1 +0.1 +0.0 +0.0 +0.2 G0TMX +0.3 G4AON +1.1 G4FRE +14.5 +14.8 +14.9 G4IRN +0.3 +0.5 +0.4 +0.3 +0.3 +0.4 +0.2 +0.3 +0.4 G4MKR +0.2 +0.0 +0.2 G4YBU -0.4 -0.2 -0.2 G4ZFE +0.5 +0.3 +0.3 +0.4 -0.1 -0.2 -0.1 -0.0 +0.1 +0.2 GI4DOH +0.4 +0.5 +0.5 +0.3 +0.2 +4.5 +4.3 +3.4 +0.2 HA1VHF -0.5 -0.4 -0.6 -0.9 -1.0 -1.1 -0.8 -0.1 +0.1 +0.2 HA5PP +8.9 +3.5 +2.1 HA6PX -0.0 +0.0 -0.1 -0.0 -0.1 -0.1 -0.1 -0.0 -0.1 -0.1 HA8TKS +0.1 +0.1 +0.6 +0.5 +0.1 +0.3 +0.2 +0.3 +0.3 +0.3 HB9BXE +0.1 +0.1 +0.1 +0.0 -0.0 +0.0 -0.0 HB9DCO -0.2 -0.2 -0.3 -0.4 -0.2 -0.4 -0.2 -0.2 -0.2 -0.1 HG0Y +7.6 +7.5 +7.3 +7.3 +7.2 +7.4 +7.6 +7.6 +7.8 +7.7 HG8A -0.9 -0.9 -0.9 -1.5 -1.1 -1.0 -0.6 -0.1 -3.3 -5.8 IK3STG +26.0 IK4VET +1.8 +1.7 +2.8 +3.5 +3.0 +3.2 +2.8 +3.5 +4.1 +3.9 IU0MVD +0.1 IZ2CPS -0.3 -0.3 -0.0 -0.0 -0.1 IZ6198SWL +0.0 +0.0 -0.3 -0.8 +0.0 -0.2 J68HZ +16.3 +16.2 +14.9 JH7CSU1 -0.4 +0.7 +0.2 -0.0 +0.1 +0.1 +0.0 +0.4 +0.8 +0.3 JI1HFJ -2.9 -4.5 -1.4 -2.8 -2.0 -1.4 -0.4 -2.0 -4.6 JJ2VLY +1.7 +1.8 +1.8 +1.5 +1.6 +1.9 +0.5 +2.8 +1.7 +1.5 JK1QLQ +1.0 +0.0 +0.0 +0.0 +0.0 +0.0 JN1ILK +0.2 +0.4 +0.3 +0.3 +0.2 +0.3 +0.1 +0.7 +0.4 +0.1 K1HTV +14.0 +14.7 +13.7 +13.5 K3PA-1 -0.0 -0.0 -0.1 -0.1 +0.0 +0.0 -0.1 +0.1 -0.1 -0.1 K3PA-2 +0.0 +0.0 -0.2 -0.3 -0.1 -0.7 -0.0 -0.4 -0.3 K4PP +0.0 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 -0.0 +0.0 -0.2 K5TR +0.2 +1.3 +0.2 +0.7 +1.8 +0.6 +0.9 +1.6 +0.8 K6FOD +0.1 +0.2 +0.0 +0.4 K7CO -0.5 +1.8 +0.1 +0.9 +0.5 +1.5 +0.4 +2.8 +0.6 +1.7 K7EK +0.3 -0.0 -0.0 +0.1 +0.0 K7MJG +0.1 +0.3 +0.0 +0.5 +0.0 +0.5 +0.1 +0.2 +0.1 +0.2 K9IMM +9.4 +1.9 +0.5 +0.4 +1.5 +0.8 +0.9 +0.9 -0.2 K9LC +0.3 +0.5 +0.0 +0.4 +0.2 +0.3 +0.2 +0.3 +0.3 +0.3 KA7OEI +0.1 +0.1 +0.0 +0.1 +0.1 +0.3 +0.3 +0.2 +0.2 +0.2 KD2OGR +0.2 +0.4 +0.1 +0.4 +0.2 +0.4 +0.3 +0.2 +0.3 +0.3 KH6LC +0.2 -0.1 -0.0 +0.1 +0.2 +0.0 +0.5 +0.5 +0.3 KM3T -0.1 -0.1 -0.2 -0.1 -0.1 -0.0 -0.1 +0.0 +0.0 -0.1 KM3T-2 +0.7 +0.8 +0.5 +0.7 +0.4 +0.9 +0.4 +0.6 +0.7 +0.5 KM3T-3 +0.1 +0.1 -0.0 +0.2 +0.1 +0.0 -0.0 +0.1 +0.2 +0.1 KO7SS +0.4 +0.6 +0.1 +0.5 +0.4 +0.8 +0.4 +0.6 +0.2 +0.5 KP3CW +0.3 +0.4 +0.0 +0.3 +0.1 +0.3 +0.2 +0.3 +0.2 +0.1 KV4TT +0.1 +0.1 +0.0 -0.0 +0.1 -0.0 LA6TPA -0.6 -1.3 -0.4 -1.6 -1.6 -1.5 -1.8 -1.2 -1.2 -0.6 LA7GIA -0.1 +0.1 -0.1 +0.0 -0.0 -0.1 -0.1 -0.2 -0.0 -0.0 LB9KJ -0.5 -0.3 -0.3 -0.6 -0.2 -0.3 -0.3 -0.6 -0.4 -0.4 LU8XW -0.3 +0.3 -0.5 -0.5 -1.1 -0.8 +0.0 -0.1 -0.8 +0.0 LY3G -3.4 LZ3CB -0.0 +0.0 +0.1 -0.1 -0.0 -0.1 -0.0 -0.0 -0.1 -0.1 LZ4AE +0.1 -0.2 -0.8 -0.7 -0.8 -0.5 -0.2 -0.4 -0.4 -0.2 LZ4UX -0.0 -0.1 +0.1 +0.1 +0.0 +0.1 +0.0 -0.1 -0.0 -0.0 LZ5DI -0.5 -0.5 -0.5 -0.5 -0.7 -0.7 -0.3 -0.3 -0.7 -0.1 MM0ZBH +0.1 +0.1 +0.1 +0.0 +0.1 +0.1 -0.0 +0.0 +0.0 -0.0 MM3NDH +0.0 -0.0 -0.1 +0.0 -0.0 +0.1 +0.1 -0.0 +0.1 +0.1 MM3NDH-2 -0.0 -0.0 -0.0 -0.0 -0.1 +0.0 +0.0 -0.2 -0.0 -0.1 MM3NDH-3 +0.2 -0.0 -0.1 -0.0 +0.1 +0.2 +0.3 -0.0 +0.1 +0.0 MW0MUT +0.2 -0.0 +0.2 +0.2 +0.1 +0.3 +0.3 +0.3 +0.4 +0.3 N6TV +0.8 +1.0 +0.0 +0.6 +0.5 +0.8 +0.5 +0.9 +0.4 +0.6 N7TUG +16.3 +16.0 +14.2 +15.8 +15.7 +16.0 +15.2 +15.5 N9CO +0.1 +0.1 -0.2 -0.1 -0.0 -0.1 -0.2 +0.2 +0.1 +0.0 ND7K -0.5 -0.5 -0.3 -0.3 -0.3 -0.4 -0.5 -0.4 -0.4 NG7M -0.4 -0.3 +0.0 -0.2 -0.1 -0.4 -0.2 +0.1 -0.1 -0.1 NN3RP +0.0 +0.0 +0.0 +0.1 +0.0 -0.1 -0.1 -0.1 -0.3 NT6Q +0.3 +0.3 +0.1 +0.4 +0.8 +0.8 +0.4 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YO5LD -1.0 -0.7 -0.7 -1.4 -1.1 -0.5 -0.4 -0.4 -0.3 ZL3X -0.6 -0.6 -1.0 -1.0 -0.5 -0.8 -1.1 -1.1 -0.2 -0.3 ZL4YL +1.3 +1.2 +1.5 +1.5 +0.9 +1.0 ZS1NN -3.8 -3.6 -3.8 -5.6 -3.9 -4.2 -4.8 -6.0 -5.0 -5.5 Last updated 2024-09-20 00:15:33 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 2024-09-20 00:15:33 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.