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
432565 RBN spots between 2025-01-20 00:00 and 23:59 UTC. 124099 spots (28.7%) were from reference skimmers (*). Average spot flow was 300 per minute from 207 active CW skimmers. 207354 spots from 204 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 2103 0.999999974 3B8GL +0.0 45 1.000000000 3D2AG +0.4 158 1.000000426 5Z4GO +0.0 11 1.000000000 7N4XCV +2.0 29 1.000002009 AA0O +0.1 114 1.000000115 AC0C-1 -0.2 2192 0.999999824 BA6KC -0.1 86 0.999999876 BD7JNA +0.0 32 1.000000000 BD8CS +0.0 27 1.000000000 BG0AJO +0.0 73 1.000000000 BG2TFW +11.9 83 1.000011904 BG6WRN +0.0 8 1.000000000 BH4RRG +0.0 59 1.000000000 BH4XDZ -0.2 45 0.999999841 BI4MPH-1 +0.0 36 1.000000000 BI4UYX -0.1 34 0.999999895 BY4XRA -0.1 51 0.999999907 CT1EYQ -0.7 2130 0.999999325 DC8YZ* -0.0 2689 0.999999978 DD5XX -2.2 1800 0.999997751 DE1LON +2.6 1865 1.000002612 DF2CK* +0.2 3758 1.000000160 DF7GB* -0.1 1824 0.999999943 DG6FL +0.2 188 1.000000152 DK0TE* -0.1 1690 0.999999905 DK1MAX -0.2 179 0.999999761 DK3UA -0.1 840 0.999999872 DK9IP -0.3 1306 0.999999728 DK9IP-1 -0.3 1612 0.999999718 DL0LA* -0.2 726 0.999999794 DL0PF +4.1 3755 1.000004084 DL1EFW +1.0 299 1.000000980 DL1HWS -0.2 2070 0.999999820 DL1HWS-3* +0.2 1061 1.000000176 DL1HWS-4 -0.3 1836 0.999999681 DL8LAS +0.0 1592 1.000000034 DL8TG* -0.1 1794 0.999999893 DL9GTB +0.5 1826 1.000000529 DM5GG +0.6 2762 1.000000627 DM6EE* -0.0 1749 0.999999967 DP5G -2.3 264 0.999997728 DP7D -0.7 1537 0.999999330 DR4W -1.3 1860 0.999998674 E28AC +1.6 144 1.000001561 EA1RX +1.2 12 1.000001227 EA1URA* +0.0 1417 1.000000038 EA2CW +0.2 1479 1.000000245 EA2RCF-4 -0.3 1053 0.999999686 EA5RQ +0.0 196 1.000000000 EA5RQ/A +0.3 53 1.000000269 EA5WU* +0.1 532 1.000000066 ES2RR* +0.0 1700 1.000000015 F4GOU +4.0 1464 1.000004012 F4VVG* -0.0 1121 0.999999991 F6IIT -1.6 2319 0.999998377 F6KGL* +0.1 1670 1.000000115 F8DGY -6.3 991 0.999993669 G0KTN* -0.0 1905 0.999999982 G3XBI +0.2 779 1.000000165 G3YPP -0.1 146 0.999999902 G4IRN* +0.1 2532 1.000000118 G4ZFE +0.1 2142 1.000000135 GI4DOH-2 -0.3 1983 0.999999659 GI4DOH-3 +0.0 77 1.000000000 HA1VHF -0.3 1676 0.999999685 HA6PX* -0.2 1764 0.999999844 HA8TKS -0.2 1172 0.999999751 HB9BXE* +0.0 1269 1.000000025 HB9DCO -0.5 1372 0.999999497 HG0Y +6.1 324 1.000006073 HG8A -0.4 1939 0.999999614 IK3STG +2.4 1600 1.000002394 IK4VET +0.7 1736 1.000000672 IK7YTT* -0.2 1960 0.999999827 IZ2CPS +0.7 37 1.000000727 IZ6198SWL +0.0 9 1.000000000 JH7CSU1 +2.7 64 1.000002657 JI1HFJ -7.1 10 0.999992865 JN1ILK +1.8 173 1.000001806 K1RA -0.7 1925 0.999999278 K2PO/7 +0.3 771 1.000000251 K3LR +0.2 893 1.000000243 K3PA-1* -0.0 817 0.999999965 K4PP* -0.1 1187 0.999999930 K5EM +0.1 565 1.000000138 K5TR -1.1 1588 0.999998940 K6FOD -0.1 406 0.999999916 K7CO* +0.1 799 1.000000137 K7EK +0.3 74 1.000000289 K9IMM* -0.0 1490 0.999999973 K9LC* +0.2 1643 1.000000245 K9QC -0.1 178 0.999999920 KA7OEI +0.1 180 1.000000057 KD2OGR +0.3 883 1.000000282 KH6LC -0.2 128 0.999999824 KM3T-2 -0.3 1194 0.999999733 KM3T-3 +0.2 1896 1.000000154 KM3T-5* -0.1 1171 0.999999869 KO7SS -0.3 523 0.999999684 KV4TT* +0.2 1468 1.000000192 LA7GIA -0.3 73 0.999999718 LB9KJ +0.3 635 1.000000287 LU6KK -0.0 24 1.000000000 LU8XW +1.2 12 1.000001184 LY3G +0.1 32 1.000000111 LZ3CB* -0.1 1117 0.999999922 LZ4AE -5.0 1839 0.999995009 LZ4UX* -0.1 1217 0.999999892 LZ5DI* -0.0 1662 0.999999994 LZ7AA +0.4 1454 1.000000417 MM0ZBH* +0.0 2354 1.000000019 MM3NDH* +0.1 1900 1.000000088 N2CR -0.4 823 0.999999637 N6TV +0.4 562 1.000000382 N7TUG +14.9 65 1.000014886 N8DXE +0.9 606 1.000000939 N9CO -0.1 1341 0.999999851 ND7K -1.2 1096 0.999998798 NG7M +0.0 790 1.000000025 NN3RP +0.2 369 1.000000187 NT6Q -5.1 937 0.999994881 NU4F* +0.0 1140 1.000000005 OE6TZE* +0.1 1349 1.000000066 OE9GHV -0.1 195 0.999999854 OH4KA -3.2 1923 0.999996815 OH6BG -0.2 1791 0.999999763 OH8KA -5.6 275 0.999994393 OK1FCJ* +0.2 2246 1.000000152 OK1HRA -3.5 1972 0.999996541 ON4EM +1.6 9 1.000001581 ON6ZQ -0.8 1643 0.999999185 OZ1AAB +0.3 554 1.000000285 OZ1BZS +0.6 467 1.000000558 OZ4ADX +0.2 108 1.000000209 PA0MBO +0.2 65 1.000000170 PA2SQ +0.3 138 1.000000338 PA8MM* +0.1 1268 1.000000073 PE5TT -0.2 1777 0.999999808 PI4CC* -0.1 2347 0.999999939 R9IR +0.1 373 1.000000102 RK3TD +0.6 1040 1.000000570 RN4WA +0.9 839 1.000000906 RU9CZD +0.5 673 1.000000504 S50ARX* +0.0 1600 1.000000015 S50U -0.2 973 0.999999834 S53A +1.0 2332 1.000001010 S53WW -1.1 1884 0.999998915 SE5E* -0.0 2143 0.999999969 SM0TCZ +2.1 164 1.000002079 SM1HEV* +0.0 767 1.000000038 SM7IUN* -0.1 2043 0.999999886 SQ5J +8.2 1714 1.000008237 SV1CDN +0.2 55 1.000000195 SZ1A* +0.0 880 1.000000033 TF3Y +1.6 1147 1.000001630 TI7W -0.2 1658 0.999999751 UA0S -0.4 681 0.999999586 UA4CC +12.5 31 1.000012492 UY2RA -2.8 376 0.999997212 V51YJ +1.2 58 1.000001229 VE3EID -0.9 2172 0.999999106 VE6AO -2.4 365 0.999997643 VE6JY +2.0 869 1.000001994 VE6WZ +2.9 1184 1.000002947 VE7CC +0.4 333 1.000000388 VK2GEL +0.9 158 1.000000943 VK2RH +0.0 14 1.000000000 VK3RASA +1.2 133 1.000001155 VR2FUN-77 +0.1 768 1.000000087 VU2PTT +0.0 110 1.000000037 VU2TUM +2.5 45 1.000002454 W1NT-2* -0.0 1806 0.999999957 W1NT-6* -0.0 2235 0.999999964 W2MV* -0.0 284 1.000000000 W2NAF +0.6 1214 1.000000560 W3DAN +1.1 646 1.000001056 W3LPL -2.7 541 0.999997333 W3OA +5.0 1718 1.000004961 W3OA-1 +0.9 756 1.000000916 W3RGA* -0.0 1604 0.999999984 W4AX +3.7 218 1.000003705 W4KAZ -4.5 560 0.999995480 W6YX -0.7 1098 0.999999308 W8WTS -0.4 1178 0.999999607 W8WWV -1.7 1394 0.999998253 WA7LNW -0.4 1362 0.999999608 WB6BEE* +0.0 1216 1.000000044 WC2L -0.5 1497 0.999999455 WC8GOP +5.2 29 1.000005161 WE9V* -0.5 1592 0.999999468 WS2C +4.0 1497 1.000004033 WS3W +1.5 627 1.000001509 WT9U +0.6 364 1.000000645 WV4P +0.3 527 1.000000297 WX7V/5 +0.2 122 1.000000243 WZ7I -3.8 2113 0.999996205 YO2CK -0.8 1745 0.999999202 YO2MAX +0.3 2054 1.000000296 YO5LD +0.2 1758 1.000000170 ZF9CW -0.3 2361 0.999999747 ZL3X* -0.1 268 0.999999894 ZL4YL +1.4 343 1.000001388 ZS1NN -3.4 64 0.999996650 Last updated 2025-01-21 00:15:39 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 0120 0119 0118 0117 0116 0115 0114 0113 0112 0111 --------------------------------------------------------------------- 2E0INH -0.0 -0.0 -0.0 +0.1 +0.1 -0.1 +0.1 +0.2 -0.0 -0.1 3B8GL +0.0 +0.0 +0.1 +0.3 -0.1 +0.2 +0.4 -0.1 -0.1 3D2AG +0.4 +0.4 +0.5 +0.4 +0.3 +0.4 -0.1 +0.5 +0.3 +0.3 3V8SS +0.2 3V9A -0.3 5Z4GO +0.0 +0.6 +0.6 -0.3 +0.0 +1.8 +0.0 +0.4 +0.6 +1.0 7N4XCV +2.0 +1.4 +1.3 +0.4 +0.7 +1.2 AA0O +0.1 +0.5 +0.4 +0.1 +0.7 +0.5 +0.4 +0.5 +0.7 +0.6 AC0C-1 -0.2 +0.0 +0.5 +0.3 +0.3 +0.3 +0.5 +0.5 +0.5 BA6KC -0.1 +0.1 -0.0 +0.1 -0.2 -0.1 -0.2 -0.0 -0.2 -0.0 BD7JNA +0.0 +0.2 +0.2 +0.1 +0.0 +0.1 +0.5 +0.0 -0.2 -0.1 BD8CS +0.0 +0.0 +0.1 +0.1 BG0AJO +0.0 +0.2 +0.2 +0.0 -0.0 +0.3 +0.4 -0.0 +0.0 BG2TFW +11.9 +10.9 +11.7 +11.4 +11.8 +11.8 +11.8 +12.0 +10.7 +11.5 BG6WRN +0.0 +0.6 +0.6 +0.6 +0.0 +0.0 +0.4 +0.1 BH4RRG +0.0 +0.3 +0.1 +0.2 -0.1 +0.1 +0.0 +0.7 +0.0 +0.1 BH4XDZ -0.2 +0.2 +0.0 +0.0 -0.2 -0.5 +0.2 -0.1 -0.2 -0.1 BI4MPH-1 +0.0 +0.1 +0.1 +0.0 +0.0 +0.5 -0.2 +0.3 -0.0 +0.0 BI4UYX -0.1 -0.1 -0.0 BY4XRA -0.1 +0.2 +0.1 -0.2 -0.2 +0.7 -0.1 +0.3 +0.1 -0.1 CT1EYQ -0.7 -1.9 -1.7 -1.3 -1.7 -1.4 -1.0 -0.8 -0.5 -0.5 CT7ANO +4.6 +0.0 DC8YZ -0.0 +0.4 -0.0 +0.0 +0.1 +0.0 +0.0 +0.1 -0.1 -0.0 DD5XX -2.2 -3.0 -2.3 -2.6 -2.4 -2.8 -2.6 -2.9 -2.6 -2.9 DE1LON +2.6 +2.7 +2.9 +2.1 +2.3 +2.1 +2.0 +2.9 +2.7 +1.0 DF1DR +0.0 +0.0 DF2CK +0.2 -0.1 +0.1 -0.0 -0.1 -0.3 -0.4 -0.6 -0.5 -0.5 DF7GB -0.1 +0.0 +0.0 +0.1 +0.1 +0.0 -0.2 +0.1 -0.1 -0.0 DG6FL +0.2 +0.3 +0.3 +0.0 DK0TE -0.1 +0.0 +0.1 +0.2 +0.2 +0.2 +0.1 +0.2 +0.0 +0.2 DK1MAX -0.2 +0.0 +0.0 +0.0 +0.0 -0.3 DK3UA -0.1 -1.5 -0.9 -0.7 +0.5 +1.4 DK9IP -0.3 -0.2 -0.2 -0.2 -0.1 -0.3 -0.2 -0.1 -0.2 -0.2 DK9IP-1 -0.3 -0.3 -0.2 -0.2 -0.2 -0.2 -0.1 -0.1 -0.2 -0.2 DL0LA -0.2 -0.3 -0.2 -0.2 -0.2 -0.2 -0.2 -0.1 -0.3 -0.2 DL0PF +4.1 +3.7 +3.7 +4.2 +3.8 +5.3 +3.9 +4.1 +3.8 DL1EFW +1.0 -1.2 +1.3 +1.5 DL1HWS -0.2 -0.2 -0.2 -0.2 -0.1 -0.2 -0.2 -0.2 +0.0 +0.2 DL1HWS-3 +0.2 +0.5 +0.4 +0.3 +0.2 +0.3 +0.3 +0.4 +0.3 +0.3 DL1HWS-4 -0.3 -0.3 -0.4 -0.3 -0.2 -0.4 -0.7 -0.7 -0.6 -0.3 DL3OBQ -14.1 -9.5 -9.3 -7.1 -2.4 -2.8 DL5RCN +11.9 +12.0 +10.8 +1.5 +11.0 +12.1 +9.2 +11.8 DL6ZB +2.2 +0.6 DL8LAS +0.0 +0.0 +0.1 -0.2 +0.1 +0.2 -0.4 +0.2 -0.3 -0.2 DL8TG -0.1 -0.0 -0.0 -0.1 -0.1 -0.1 -0.1 -0.1 -0.2 -0.0 DL9GTB +0.5 +0.7 +0.6 +0.6 +0.0 +0.5 +0.4 +0.5 +0.4 DM5GG +0.6 +0.0 +0.1 +0.5 +0.2 +0.7 +0.5 +0.8 +0.2 +0.3 DM6EE -0.0 -0.0 -0.1 -0.1 -0.2 -3.2 -0.1 -0.8 -0.8 DM7EE +0.1 +0.2 DP5G -2.3 -3.2 -3.4 -3.3 -3.0 -3.7 DP7D -0.7 -0.7 -0.3 -0.1 -0.1 +6.9 +11.1 +7.8 -0.1 DR4W -1.3 -3.6 -3.7 -3.4 -2.1 -4.1 -3.8 -3.9 -2.9 -3.7 E28AC +1.6 +2.9 +1.5 +1.6 +1.7 +1.1 +1.3 +1.0 +1.8 +2.1 EA1RX +1.2 -0.3 -1.1 -1.6 -2.5 -0.4 -0.8 EA1URA +0.0 -0.1 -0.5 -0.2 -0.2 -0.1 -0.2 +0.0 +0.1 +0.3 EA2CIA +0.6 EA2CW +0.2 +0.3 +0.4 +0.0 +0.1 +0.1 +0.1 +0.2 +0.1 +0.2 EA2RCF-4 -0.3 -0.5 -0.5 -0.3 -0.3 -0.3 -0.3 -0.2 -0.2 -0.2 EA4FIT +1.0 EA5RQ +0.0 -0.0 +0.0 +0.2 +0.1 +0.4 +0.4 +0.0 +0.2 EA5RQ/A +0.3 +0.0 +0.5 +0.0 +1.4 +0.0 -0.3 -0.0 +0.5 EA5WU +0.1 -0.0 -0.1 +0.0 -0.1 -0.1 -0.1 -0.1 -0.1 ES2RR +0.0 -0.0 -0.0 -0.0 -0.0 -0.0 -0.0 -0.0 -0.1 +0.0 ES5PC -0.0 -0.1 +0.0 -0.0 -0.0 -0.2 +0.0 -0.0 +0.0 ET3AA -11.7 -11.8 -13.2 -12.0 -12.0 F4GOU +4.0 +3.8 +4.0 +3.8 +3.7 +4.0 +3.3 +3.8 +4.0 +4.4 F4VVG -0.0 +0.0 +0.0 +0.0 +0.1 +0.0 -0.1 -0.1 -0.2 -0.0 F5AHD +0.7 +0.7 +0.6 F6IIT -1.6 -2.0 -1.8 +5.4 -2.6 -2.1 -1.8 -1.5 F6KGL +0.1 +0.3 +0.3 +0.0 +0.1 +0.2 +0.2 +0.2 F6KOP +1.4 F8DGY -6.3 -6.5 -2.7 -4.6 F8RTL +1.2 F8UKP +0.0 G0KTN -0.0 -0.0 +0.1 +0.1 -0.0 -0.0 +0.0 +0.1 -0.1 -0.1 G0TMX -0.3 G3XBI +0.2 +0.3 +0.3 +0.3 +0.0 +0.3 +0.4 +0.1 +0.3 +0.4 G3YPP -0.1 +0.1 +0.1 +0.2 -0.0 -0.1 +0.0 +0.0 -0.3 -0.1 G4IRN +0.1 +0.0 +0.2 +0.3 +0.3 +0.4 +0.3 +0.2 -0.0 -0.1 G4ZFE +0.1 +0.2 +0.3 +0.3 +0.3 +0.5 +0.2 +0.4 -0.0 +0.1 GI4DOH-2 -0.3 -0.3 -0.2 +0.2 +0.1 +0.3 +0.2 +0.2 +0.0 -0.0 GI4DOH-3 +0.0 -0.3 +0.7 +0.3 +0.2 +0.0 +0.5 +0.4 +0.1 +0.2 GX0FRE-5 +0.2 HA1VHF -0.3 -0.0 -0.1 -0.6 -0.7 -0.7 -0.6 -0.8 -0.6 -0.1 HA5PP +2.1 HA6PX -0.2 +0.0 +0.0 +0.0 -0.0 +0.0 +0.4 -0.0 -0.1 HA8TKS -0.2 -0.3 -0.4 -0.3 -0.1 -0.5 -0.5 +0.0 +0.7 HB9BXE +0.0 +0.1 +0.1 -0.0 +0.1 +0.1 -0.1 +0.0 +0.1 +0.1 HB9DCO -0.5 -0.6 -0.5 -0.3 -0.5 -0.4 -0.5 -0.4 -0.4 -0.4 HG0Y +6.1 +6.1 +6.0 +6.3 +5.7 +5.5 HG8A -0.4 -1.7 -1.8 -0.8 -0.4 -0.2 -0.6 -0.3 -1.0 -0.2 IK3STG +2.4 +2.5 +3.6 +3.0 +2.9 +3.1 +2.6 +3.0 +2.8 +2.7 IK4VET +0.7 +0.5 +0.8 +0.5 +0.6 +0.7 +0.4 +0.7 +0.6 +1.0 IK7YTT -0.2 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 +0.0 -0.2 -0.0 IZ2CPS +0.7 +1.0 +0.7 +1.1 +1.3 IZ6198SWL +0.0 +0.4 +0.0 +0.0 +0.0 +2.4 JG1DLY -0.3 -0.6 -0.5 -0.1 JH7CSU1 +2.7 +2.1 +1.4 +1.8 +1.1 +1.6 +1.1 +1.7 +2.2 +1.6 JI1HFJ -7.1 -2.0 -5.1 -2.8 -3.5 -4.2 -2.2 -1.3 -1.3 -4.0 JN1ILK +1.8 +1.2 +0.1 +0.1 +0.2 +1.1 +3.4 +0.9 +0.4 +0.2 K0GB +1.6 +3.0 +0.8 K1RA -0.7 -0.1 -0.3 -0.3 -0.5 -0.6 -0.3 -0.2 -0.6 -0.6 K2PO/7 +0.3 +0.2 +0.3 +0.2 +0.2 +0.5 +0.3 +0.5 +0.6 +0.5 K3LR +0.2 +1.1 +1.3 +0.3 -0.0 +0.3 +0.3 +0.4 +0.2 +0.5 K3PA-1 -0.0 -0.0 +0.0 +0.1 -0.1 +0.1 +0.0 +0.1 -0.0 -0.0 K3PA-2 +14.9 +15.1 +14.9 +14.9 +15.1 K4PP -0.1 -0.1 -0.1 -0.1 +0.0 -0.2 -0.1 +0.1 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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.
DF7GB ES2RR KM3T-5 LZ3CB LZ4UX MM3NDH OE9GHV WB6BEE Last updated 2025-01-21 00:15:49 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.