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
371741 RBN spots between 2024-12-20 00:00 and 23:59 UTC. 107068 spots (28.8%) were from reference skimmers (*). Average spot flow was 258 per minute from 207 active CW skimmers. 167522 spots from 199 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* +0.1 1769 1.000000122 3B8GL +0.0 82 1.000000049 3D2AG +0.4 71 1.000000357 3V8SS -2.5 304 0.999997481 5Z4GO +0.0 15 1.000000000 7N4XCV +0.6 13 1.000000640 AA0O +0.0 29 1.000000000 AC0C-1 +0.1 1021 1.000000099 BA6KC -0.1 44 0.999999909 BD7JNA +0.0 14 1.000000000 BD8CS -0.1 33 0.999999892 BG2TFW +10.4 55 1.000010447 BG4GOV +0.4 15 1.000000369 BH4RRG -0.3 43 0.999999668 BH4XDZ +0.1 24 1.000000149 BI4MPH-1 +0.2 23 1.000000155 BY4XRA +0.0 31 1.000000000 CT1EYQ -0.8 1610 0.999999229 DC8YZ* +0.0 2080 1.000000027 DD5XX -3.5 1181 0.999996509 DE1LON +1.4 1443 1.000001412 DF2CK* -0.0 2783 0.999999950 DF7GB* -0.0 1415 0.999999997 DK0TE* -0.0 1345 0.999999974 DK1MAX +0.0 52 1.000000000 DK9IP -0.3 959 0.999999729 DK9IP-1* -0.1 1282 0.999999929 DL0LA -0.3 1178 0.999999724 DL0PF +4.0 970 1.000003983 DL1HWS* -0.0 1587 0.999999965 DL1HWS-3 +0.2 793 1.000000177 DL3OBQ +0.6 49 1.000000581 DL5RCN +12.7 142 1.000012710 DL8LAS +6.9 1590 1.000006879 DL8TG* +0.0 979 1.000000025 DL9GTB +0.7 1501 1.000000651 DM5GG +0.8 2167 1.000000757 DM6EE* +0.0 1278 1.000000029 DP7D +0.3 641 1.000000345 DR4W -3.6 1312 0.999996394 DR5X -1.2 1594 0.999998831 EA1RX -3.8 21 0.999996150 EA1URA* -0.1 1235 0.999999915 EA2CW +0.2 1386 1.000000190 EA2RCF-4 -0.2 903 0.999999759 EA5RQ +0.3 373 1.000000252 EA5RQ/A +0.2 88 1.000000162 EA5WU* -0.0 1531 0.999999979 ES2RR* -0.1 1282 0.999999923 ES5PC* -0.0 1046 0.999999992 ET3AA -11.4 132 0.999988639 F4GOU +4.1 1031 1.000004135 F4VVG* -0.0 608 0.999999986 F6IIT -1.0 1880 0.999998987 F6KGL +0.2 1473 1.000000181 F8UKP -1.4 689 0.999998557 G0KTN* +0.0 1482 1.000000014 G3XBI +0.4 583 1.000000440 G3YPP +0.0 124 1.000000000 G4AON +1.0 202 1.000000988 G4IRN +0.3 1835 1.000000257 G4ZFE +0.3 1650 1.000000339 GI4DOH* +0.2 632 1.000000242 GI4DOH-2* -0.1 1369 0.999999880 HA1VHF* -0.1 1477 0.999999934 HA6PX* +0.0 1457 1.000000017 HA8TKS* +0.1 855 1.000000129 HB9BXE -0.1 1230 0.999999935 HB9DCO -0.5 1123 0.999999541 HG0Y +6.7 272 1.000006658 HG8A -0.4 1605 0.999999648 IK3STG +3.8 773 1.000003822 IK4VET +0.4 1656 1.000000388 IK7YTT -0.2 1876 0.999999844 JH7CSU1 +1.8 58 1.000001845 JI1HFJ -2.2 20 0.999997840 JN1ILK -3.3 166 0.999996726 K1RA* +0.0 1537 1.000000048 K2PO/7 -5.0 11 0.999995035 K3LR -0.2 554 0.999999837 K3PA-1* -0.1 832 0.999999899 K3PA-2 +15.0 196 1.000015041 K4PP* -0.1 982 0.999999900 K5EM -0.2 480 0.999999789 K5TR +0.2 1021 1.000000164 K5TR-2* -0.0 804 0.999999992 K6FOD -0.0 389 0.999999964 K7CO +0.4 720 1.000000352 K7EK +0.1 228 1.000000062 K9IMM* -0.0 1446 0.999999981 K9LC +0.1 1523 1.000000130 K9QC +0.1 120 1.000000099 KA7OEI +0.3 138 1.000000264 KD2OGR +0.2 584 1.000000155 KH6LC +0.0 84 1.000000048 KM3T* +0.0 461 1.000000021 KM3T-2 +0.1 1382 1.000000075 KM3T-3 +0.2 1601 1.000000183 KM3T-5* +0.1 987 1.000000052 KO7SS -0.1 364 0.999999948 KV4TT* +0.1 1018 1.000000115 LA6TPA -5.5 426 0.999994504 LA7GIA -0.0 183 0.999999960 LB9KJ +0.2 305 1.000000200 LU6KK +0.0 13 1.000000000 LU8XW +0.0 12 1.000000000 LZ3CB* -0.1 944 0.999999906 LZ4AE -1.4 1296 0.999998578 LZ4UX -0.1 1055 0.999999891 LZ5DI* +0.2 1489 1.000000157 LZ7AA +0.6 1130 1.000000596 M0ORD +6.5 21 1.000006451 MM0ZBH* -0.0 2060 0.999999961 MM3NDH +0.1 1492 1.000000097 N6TV +0.2 519 1.000000156 N7TUG +16.3 8 1.000016331 N8DXE +1.2 711 1.000001242 N9CO* -0.0 1324 0.999999975 ND7K -0.6 805 0.999999393 NG7M -0.1 610 0.999999944 NN3RP -0.3 404 0.999999729 NT6Q +0.4 103 1.000000419 NU4F* -0.1 1028 0.999999918 OE6ADD* +0.1 401 1.000000080 OE6ADD/6 -0.2 60 0.999999763 OE6TZE* +0.0 1081 1.000000004 OE9GHV -1.7 922 0.999998310 OH4KA -2.5 1622 0.999997492 OH6BG -0.4 1433 0.999999550 OK1FCJ +0.2 1842 1.000000236 OK1HRA -3.4 1636 0.999996556 OL9A +1.7 684 1.000001706 ON6ZQ -0.4 1141 0.999999554 OZ1AAB* +0.1 420 1.000000110 OZ1BZS +0.3 295 1.000000294 OZ4ADX +0.3 167 1.000000327 PA8MM* +0.2 892 1.000000189 PC2A +0.1 143 1.000000119 PE1RDP +0.2 88 1.000000162 PE5TT +0.4 1281 1.000000357 PI4CC* -0.1 1954 0.999999873 R1LB -2.0 446 0.999997955 R6YY -0.3 107 0.999999682 RK3TD +1.3 595 1.000001333 RN4WA +1.2 934 1.000001192 RU9CZD -10.7 552 0.999989264 S50ARX -0.1 1576 0.999999887 S50U* -0.1 495 0.999999922 S53A -0.3 1592 0.999999722 S53F +3.2 1412 1.000003201 S53WW -0.4 1572 0.999999563 SE5E* +0.0 1845 1.000000049 SM7IUN* +0.1 742 1.000000071 SQ5J +8.1 1270 1.000008113 SV1CDN +0.5 140 1.000000511 SZ1A* +0.1 1542 1.000000121 TF3Y +1.6 1502 1.000001582 TI7W -0.6 1628 0.999999405 UA0S -0.9 423 0.999999102 UD4FD -1.7 164 0.999998348 V51YJ +0.3 21 1.000000340 VE3EID -0.4 2137 0.999999648 VE6JY +1.1 952 1.000001096 VE6WZ +3.7 796 1.000003723 VE7CC +0.4 325 1.000000427 VK2GEL +1.7 143 1.000001691 VK3RASA +0.4 100 1.000000357 VK6ANC -0.5 102 0.999999537 VR2FUN-77 -0.4 504 0.999999601 VU2CPL +0.1 67 1.000000124 VU2PTT +0.0 73 1.000000049 W1NT-2* -0.0 1606 0.999999992 W1NT-6* -0.1 2292 0.999999929 W2LB +0.0 74 1.000000000 W2MV -0.1 217 0.999999934 W2NAF +0.9 1004 1.000000867 W3DAN +1.0 739 1.000001040 W3LPL -2.0 537 0.999998004 W3OA* -0.0 1411 0.999999997 W3RGA* -0.1 1230 0.999999865 W4AX +4.2 78 1.000004160 W4KAZ -2.0 1031 0.999997970 W6YX -0.1 330 0.999999914 W8WTS -0.4 1092 0.999999579 W8WWV -1.7 1019 0.999998250 WA7LNW* +0.2 1122 1.000000246 WB6BEE* -0.0 1264 0.999999957 WC2L* +0.1 1099 1.000000133 WC8GOP +7.7 62 1.000007710 WE9V -0.2 1423 0.999999835 WS2C +3.7 1253 1.000003723 WS3W +2.9 268 1.000002886 WV4P* +0.1 1175 1.000000078 WZ7I* +0.0 2045 1.000000020 YO2CK +1.3 1424 1.000001276 YO2MAX -0.4 655 0.999999615 YO5LD +0.2 1257 1.000000197 ZF9CW -0.2 919 0.999999788 ZS1NN -3.6 19 0.999996371 Last updated 2024-12-21 00:15:34 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 1220 1219 1218 1217 1216 1215 1214 1213 1212 1211 --------------------------------------------------------------------- 2E0INH +0.1 +0.2 +0.0 +0.0 +0.1 +0.0 +0.0 +0.1 +0.1 3B8CW +1.2 3B8GL +0.0 +0.1 -0.1 -0.4 +0.2 -0.3 3D2AG +0.4 +0.2 +0.4 +0.2 +1.0 +0.8 +0.8 +0.7 +0.4 +0.8 3V8SS -2.5 -3.0 -2.8 -2.5 -2.1 -2.6 -2.1 -2.3 -2.4 5Z4GO +0.0 +1.4 +0.0 +0.3 +0.4 +0.3 +1.7 7N4XCV +0.6 +0.2 -0.6 +0.5 +0.2 +2.5 +0.5 AA0O +0.0 +0.0 +0.4 +0.0 +0.1 +0.4 +0.4 +0.1 +0.2 +0.2 AA4VV -0.0 -0.1 -0.0 +0.0 -0.0 +0.1 AC0C-1 +0.1 +0.1 -0.0 +0.1 +0.1 +0.2 +0.0 -0.3 BA6KC -0.1 +0.0 -0.1 -0.1 -0.1 -0.0 +0.1 -0.1 BD7JNA +0.0 -0.3 -0.2 -0.1 +0.0 -0.2 BD8CS -0.1 -0.0 +0.2 +0.0 +0.2 -0.0 +0.0 -0.2 -0.2 -0.1 BG0AJO -0.2 -0.0 +0.5 BG2TFW +10.4 +10.9 +11.0 +11.2 +10.7 +9.4 +9.3 +9.3 +10.5 +9.4 BG4GOV +0.4 +0.0 +0.0 +0.2 +0.3 +0.5 +0.3 +0.3 +0.0 +0.3 BH4RRG -0.3 +0.0 +0.7 +0.3 -0.3 +0.1 +0.2 -1.7 +0.1 +0.1 BH4XDZ +0.1 +0.0 +0.1 +0.0 -0.1 +0.0 -0.1 +0.3 +0.1 +0.2 BI4MPH-1 +0.2 +0.0 +0.0 +0.1 +0.0 +0.1 +0.2 +0.5 +0.0 +0.0 BY4XRA +0.0 +0.5 +0.0 +0.2 +0.0 +0.1 +0.2 +0.3 +0.2 +0.5 CT1EYQ -0.8 -0.5 -0.6 -0.8 -1.2 -1.7 -1.5 -1.3 -1.3 -1.3 DC8YZ +0.0 +0.0 +0.0 -0.0 +0.0 -0.1 -0.0 +0.0 +0.1 -0.0 DD5XX -3.5 -1.9 -3.1 -2.8 -2.5 -3.6 -4.5 -4.2 -3.4 -3.3 DE1LON +1.4 +2.7 +0.8 -0.4 -0.6 -0.6 -0.4 +0.3 +1.7 +2.0 DF2CK -0.0 +0.3 -0.0 +0.2 -0.2 -0.2 -0.3 -0.4 -0.2 -0.2 DF7GB -0.0 +0.1 -0.0 +0.0 -0.1 -0.0 +0.1 +0.0 +0.0 +0.0 DJ1RK -0.4 -0.9 -0.7 -0.3 +0.0 -0.4 -0.2 -0.0 -0.4 DK0TE -0.0 +0.1 +0.3 +0.1 +0.1 -0.1 -0.1 -0.1 +0.0 +0.0 DK1MAX +0.0 +0.0 -0.0 -0.2 -0.2 -0.1 +0.0 -0.1 DK3UA -7.1 -7.5 -8.0 -7.4 -2.0 -3.3 -8.6 -8.7 -6.8 DK8NE +0.0 DK9IP -0.3 -0.3 -0.4 -0.4 -0.4 -0.8 -0.8 -0.3 -0.5 -0.5 DK9IP-1 -0.1 -0.1 -0.1 -0.2 -0.1 -0.4 -0.4 -0.1 -0.1 -0.1 DL0LA -0.3 -0.3 -0.1 -0.2 -0.3 -0.3 -0.4 -0.3 -0.3 -0.3 DL0PF +4.0 +4.0 +3.8 +3.9 DL1HWS -0.0 -0.1 -0.0 -0.1 -0.1 -0.1 -0.0 +0.0 -0.0 -0.0 DL1HWS-3 +0.2 +0.1 +0.2 +0.1 +0.1 +0.2 +0.1 +0.2 +0.3 DL3OBQ +0.6 +0.7 +5.5 +12.1 +0.1 +0.2 DL5RCN +12.7 +12.3 +11.6 +11.6 DL8LAS +6.9 +12.3 +4.5 +4.9 -4.8 -4.7 -4.4 -4.6 -4.5 DL8TG +0.0 -0.1 -0.1 -0.0 -0.0 -0.4 +0.0 DL9GTB +0.7 +0.4 +0.6 +0.5 +0.8 +0.7 +0.6 +0.6 +0.4 +0.6 DM5GG +0.8 +0.9 +0.7 +0.4 +0.5 +0.0 +0.6 +0.5 -0.1 +0.6 DM6EE +0.0 -0.0 +0.0 +0.0 +0.1 -0.0 -0.0 +0.1 +0.0 +0.0 DM7EE +0.3 +0.0 DP5G +0.0 DP7D +0.3 +0.4 +0.3 +0.7 +0.9 +0.4 +0.8 +0.6 +10.4 +8.3 DR4W -3.6 -2.8 -3.4 -3.5 -3.7 -4.2 -4.1 -3.5 -3.6 -3.5 DR5X -1.2 -2.5 E28AC +3.4 +3.3 +0.7 +0.0 +7.1 EA1RX -3.8 -1.3 -3.7 -2.0 -0.8 +1.8 +2.5 -1.4 -1.4 EA1URA -0.1 +0.5 +0.1 -0.0 -0.2 -0.2 -0.3 -0.1 -0.3 -0.3 EA2CW +0.2 +0.3 +0.1 +0.1 +0.3 +0.2 +0.0 -0.0 +0.0 +0.1 EA2RCF-4 -0.2 -0.2 -0.3 -0.3 -0.4 -0.5 -0.6 -0.4 -0.3 -0.2 EA4FIT +1.2 +1.2 +0.2 EA5RQ +0.3 +0.0 -0.1 +0.4 +0.5 +0.3 +0.4 +0.2 +0.5 +0.4 EA5RQ/A +0.2 +1.2 -0.3 +0.0 +0.1 +0.1 -0.4 +0.0 EA5WU -0.0 -0.1 -0.0 -0.1 -0.2 -0.0 -0.0 -0.0 -0.1 ES2RR -0.1 -0.1 -0.1 -0.1 -0.1 -0.0 -0.0 +0.1 +0.1 -0.0 ES5PC -0.0 +0.1 -0.1 -0.0 -0.1 -0.0 -0.1 +0.1 -0.0 -0.0 ET3AA -11.4 -12.3 -12.7 -12.7 -12.9 -12.6 -13.2 -12.9 -12.7 -12.1 F1TRE -1.8 F4GOU +4.1 +3.3 +3.9 +3.5 +3.8 +4.1 +3.7 +3.2 +3.7 +3.8 F4VVG -0.0 +0.0 -0.0 -0.1 -0.2 -0.2 -0.0 +0.0 +0.2 -0.0 F6IIT -1.0 -0.6 -0.8 -0.6 -0.6 -1.3 -1.0 -1.1 -1.3 -1.0 F6KGL +0.2 +0.3 +0.2 +0.2 +0.3 +0.3 +0.2 +0.0 +0.1 +0.3 F8UKP -1.4 -1.2 -1.6 -1.6 -1.6 -2.0 -2.4 -1.7 -1.7 G0KTN +0.0 +0.2 +0.1 +0.1 +0.2 +0.1 +0.1 +0.0 -0.1 +0.0 G0TMX -0.1 G3XBI +0.4 +0.5 +0.3 +0.2 +0.2 +0.1 G3YPP +0.0 +0.5 -0.1 -0.1 -0.1 +0.1 +0.1 +0.2 +0.1 G4AON +1.0 +0.7 +1.5 +1.1 +1.5 +0.8 +1.0 G4FRE +1.1 G4HSO -0.8 -0.3 +0.0 -1.1 -1.1 G4IRN +0.3 +0.2 +0.4 +0.3 +0.3 +0.5 +0.1 +0.1 +0.1 G4IRN-1 +9.9 G4ZFE +0.3 +0.3 +0.3 +0.2 +0.3 -0.1 -0.2 +0.3 +0.1 +0.2 GI4DOH +0.2 +0.1 +0.2 +0.1 +0.2 +0.9 +1.0 GI4DOH-2 -0.1 -0.1 -0.0 +0.1 +0.6 +0.4 +0.1 +0.2 +0.1 +0.0 HA1VHF -0.1 +0.1 -0.1 -0.2 -0.3 -0.4 -0.7 -0.4 -0.4 -0.3 HA5PP +3.0 HA6PX +0.0 +0.0 -0.0 -0.0 -0.1 -0.1 -0.1 -0.0 +0.0 -0.0 HA8TKS +0.1 +0.2 +0.2 +0.1 +0.1 +0.2 +0.1 +0.2 +0.1 +0.1 HB9BXE -0.1 +0.1 +0.1 +0.1 +0.1 -0.0 -0.1 +0.0 +0.1 +0.1 HB9DCO -0.5 -0.4 -0.5 -0.4 -0.6 -0.5 -0.6 -0.6 -0.4 -0.6 HG0Y +6.7 +6.6 +6.4 +6.1 +6.1 +6.3 +6.5 +6.5 HG8A -0.4 -0.3 -0.0 -0.7 -0.6 -2.1 -2.1 -0.3 -0.1 -0.1 IK2LFF +0.0 IK3STG +3.8 +3.5 +3.3 +2.9 +2.9 +3.0 +3.0 +3.3 +2.8 +3.3 IK4VET +0.4 +0.4 +0.4 +0.4 +0.4 +0.4 +0.4 +0.3 +0.4 +0.4 IK7YTT -0.2 -0.1 -0.1 -0.1 -0.1 -0.1 -0.0 IZ2CPS +0.0 +0.0 +0.0 -0.8 -0.7 -0.2 -0.9 JE1TRV +0.0 +7.1 +14.3 JG1DLY -0.2 -0.1 JH4UTP -2.7 -2.2 -1.6 -2.4 JH7CSU1 +1.8 +1.8 +1.2 +0.9 +1.8 +2.5 +3.9 +1.5 JI1HFJ -2.2 -4.4 -2.9 -2.8 -2.0 +1.4 +1.2 -4.2 -2.6 -2.2 JJ2VLY -0.1 -1.6 -3.4 JN1ILK -3.3 -2.4 -1.8 -0.4 -1.0 -3.1 -3.3 -3.4 -1.7 -2.1 K1RA +0.0 -0.3 -0.2 +0.4 -0.0 -0.5 +0.0 K2PO/7 -5.0 -12.5 -8.0 -5.9 -6.3 -1.5 -1.5 -9.3 -8.3 -6.0 K3LR -0.2 -0.2 +0.3 +0.5 +0.5 +0.1 +0.6 +0.3 +0.4 +0.3 K3PA-1 -0.1 +0.0 -0.0 -0.1 -0.0 -0.1 -0.1 -0.0 +0.0 -0.0 K3PA-2 +15.0 +14.9 +15.3 +15.0 +15.4 +15.4 +1.2 -1.7 -1.1 -1.9 K4PP -0.1 -0.1 -0.1 +0.0 -0.1 -0.0 -0.1 -0.0 -0.2 -0.2 K5EM -0.2 +0.3 +0.5 +0.3 +0.3 +1.2 +0.4 +0.2 +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.
DF7GB ES2RR KM3T LZ3CB LZ4UX MM3NDH WB6BEE Last updated 2024-12-21 00:15:42 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.