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
280460 RBN spots between 2025-05-06 00:00 and 23:59 UTC. 67873 spots (24.2%) were from reference skimmers (*). Average spot flow was 195 per minute from 202 active CW skimmers. 126495 spots from 197 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 ------------------------------------- 3D2AG +0.5 30 1.000000475 3V9A -0.9 726 0.999999124 5Z4GO +0.8 5 1.000000803 7N4XCV +0.7 10 1.000000713 AC0C-1 +0.1 99 1.000000144 BA6KC +0.1 107 1.000000085 BG0AJO -0.1 102 0.999999907 BG0AJO/0 +0.0 25 1.000000000 BG2TFW +8.4 95 1.000008381 BG4GOV +0.0 9 1.000000000 BH4RRG +0.0 18 1.000000000 BH4RRG- +0.0 20 1.000000000 BH4XDZ -1.3 28 0.999998726 BI4MPH-1 +0.0 12 1.000000000 BY4XRA -0.1 43 0.999999917 CT1EYQ -0.1 802 0.999999916 CX6VM +2.7 118 1.000002661 DD5XX +0.7 1786 1.000000657 DE1LON +2.0 1004 1.000002039 DF2CK +1.5 2792 1.000001523 DF7GB* +0.1 1464 1.000000069 DK0TE +0.8 1287 1.000000774 DK3UA* +0.4 498 1.000000390 DK3WW +0.2 1539 1.000000219 DK9IP +0.0 793 1.000000006 DK9IP-1* +0.0 1346 1.000000026 DL0LA* -0.0 694 0.999999978 DL0PF +8.4 2289 1.000008424 DL1HWS +0.3 1617 1.000000299 DL1HWS-3 +0.6 1168 1.000000565 DL1HWS-4 +0.2 214 1.000000172 DL5RCN +12.6 179 1.000012608 DL8LAS +0.3 805 1.000000269 DL9GTB -0.1 990 0.999999870 DM5GG* -0.2 2347 0.999999766 DM6EE* +0.0 1543 1.000000024 DO4DXA* +0.1 1988 1.000000077 DO4ZT* +0.1 1108 1.000000102 DR4W -4.9 1033 0.999995084 E28AC +0.1 32 1.000000136 EA2CW +0.2 822 1.000000220 EA2RCF-4 +0.4 590 1.000000415 EA5RQ -0.3 15 0.999999683 EA5RQ/A +0.0 8 1.000000000 EA5WU* +0.0 1237 1.000000008 ES2RR* -0.1 1295 0.999999886 ES5PC* +0.0 1911 1.000000021 F4BPO -1.1 561 0.999998884 F4GOU +5.1 1074 1.000005058 F4VVG* -0.4 598 0.999999617 F6IIT -1.0 1225 0.999998969 G0KTN +0.3 1334 1.000000254 G3XBI +0.2 232 1.000000154 G3YPP +0.7 119 1.000000737 G4IRN +0.6 1465 1.000000603 G4ZFE +0.2 1172 1.000000224 GI4DOH-2* +0.1 1184 1.000000129 GX0FRE -0.0 248 0.999999997 HA1VHF +0.2 1661 1.000000244 HA6PX* +0.1 1617 1.000000067 HA8TKS +0.3 1061 1.000000329 HB9BXE +0.2 1309 1.000000186 HB9DCO -0.2 1036 0.999999793 HB9GVO +0.7 40 1.000000714 HG8A +0.6 1680 1.000000589 IK4VET +4.1 1939 1.000004137 IK7YTT +0.0 1368 1.000000048 IT9GSF +0.7 232 1.000000737 JI1HFJ +4.3 17 1.000004334 JJ2VLY +14.8 66 1.000014773 JN1ILK -0.0 232 0.999999957 K1RA +0.0 217 1.000000040 K2PO/7 +0.6 365 1.000000579 K3PA-1 +0.1 356 1.000000064 K3PA-2 +0.0 33 1.000000000 K4PP* +0.1 455 1.000000086 K5EM +0.8 267 1.000000791 K5TR +0.8 337 1.000000823 K6FOD +0.3 201 1.000000263 K7CO -0.1 363 0.999999876 K7EK +0.5 144 1.000000456 K9IMM +0.2 506 1.000000168 K9LC +0.4 578 1.000000404 K9QC +0.3 49 1.000000258 KC4YVA -3.2 231 0.999996808 KD2OGR +0.3 318 1.000000348 KD7EFG +0.4 163 1.000000398 KH6LC +0.2 31 1.000000230 KM3T-2 +0.4 626 1.000000440 KM3T-3* +0.1 883 1.000000095 KM3T-5* -0.1 510 0.999999877 KO7SS +0.3 198 1.000000330 KP2RUM +0.2 805 1.000000213 KP3CW +0.2 349 1.000000225 KV4TT* -0.0 600 0.999999961 LA6TPA -2.6 446 0.999997378 LB9KJ +1.1 360 1.000001056 LU6KK +0.0 12 1.000000000 LZ3CB -0.0 811 0.999999968 LZ4AE +1.1 1462 1.000001107 LZ4UX* -0.1 949 0.999999919 LZ5DI +1.5 1611 1.000001457 LZ7AA +1.3 1158 1.000001278 MM0GPZ -0.2 1255 0.999999798 MM0ZBH -0.6 1597 0.999999449 N2CR -0.0 374 0.999999980 N6TV +0.8 219 1.000000758 N7OR -0.1 104 0.999999863 N8DXE +2.8 15 1.000002845 N9CO +0.2 283 1.000000186 ND7K -0.2 362 0.999999826 NG7M +0.4 286 1.000000368 NN3RP +0.5 189 1.000000548 NT6Q -4.1 390 0.999995890 NU4F* +0.0 475 1.000000029 OE3KLU-3 +12.8 30 1.000012826 OE6TZE -0.4 19 0.999999625 OE9GHV* -0.1 478 0.999999940 OG66X +0.1 241 1.000000118 OH4KA +0.4 312 1.000000421 OH6BG* +0.0 1821 1.000000019 OH8KA -4.6 1488 0.999995352 OK1FCJ +0.5 1625 1.000000533 OK1HRA -4.4 1552 0.999995568 OK4QRO +1.9 1462 1.000001893 ON6ZQ* +0.1 1113 1.000000078 OZ1BZS +0.5 192 1.000000536 OZ4ADX* +0.1 473 1.000000141 PA8MM* +0.2 501 1.000000186 PE5TT +0.4 1148 1.000000417 PI4CC +0.2 1653 1.000000234 PY2KJ +1.1 23 1.000001137 PY2PE +5.6 10 1.000005592 R1LB -0.1 528 0.999999932 R4NCU -0.4 142 0.999999649 R9IR +0.5 1020 1.000000535 RK3TD +0.2 767 1.000000232 RK3TD-2* -0.0 897 0.999999965 RN4WA +1.0 1007 1.000001033 RU9CZD -0.0 936 0.999999967 S50U +0.4 104 1.000000422 S53A +0.5 1025 1.000000516 S53F +1.1 655 1.000001096 S53WW +0.1 1518 1.000000143 SE5E +0.4 1893 1.000000447 SM0TCZ -0.8 21 0.999999207 SM1HEV +0.1 384 1.000000076 SM7IUN* +0.1 1042 1.000000118 SQ5J +9.0 446 1.000008977 SV1CDN +1.0 7 1.000001020 SZ1A -2.1 1311 0.999997937 TF3Y +1.4 264 1.000001445 TI7W +0.5 694 1.000000547 UT5R +4.6 898 1.000004626 UT5R-1 +2.2 1085 1.000002199 UY2RA -2.6 719 0.999997447 V51YJ +1.5 12 1.000001494 VE3EID +0.7 803 1.000000657 VE6JY +3.5 280 1.000003460 VE6WZ +4.8 386 1.000004763 VE7CC +1.0 87 1.000001009 VK2GEL +0.2 53 1.000000224 VK2RH +0.0 5 1.000000000 VK3RASA +0.5 43 1.000000498 VK6ANC +0.1 39 1.000000122 VR2FUN-77 +0.8 733 1.000000795 VU2PTT +0.8 72 1.000000759 VU2TUM +0.3 166 1.000000253 W1NT-2 -0.0 310 0.999999977 W1NT-6* -0.1 743 0.999999933 W2MV +0.8 72 1.000000791 W2NAF +1.1 495 1.000001057 W3DAN +1.6 18 1.000001584 W3OA +0.1 643 1.000000146 W3RGA* -0.1 335 0.999999851 W3UA +0.1 52 1.000000069 W4AX +4.9 85 1.000004905 W4KAZ -0.2 568 0.999999781 W6YX +0.5 378 1.000000515 W8WTS* -0.0 321 0.999999978 W8WWV -0.8 562 0.999999243 WA7LNW +0.3 505 1.000000309 WB6BEE +0.0 489 1.000000006 WC2L +0.4 581 1.000000374 WC8GOP +11.0 36 1.000011009 WE9V +3.3 636 1.000003313 WS2C +6.3 390 1.000006267 WS3W +0.6 97 1.000000587 WT9U +0.6 80 1.000000603 WV4P* -0.0 285 0.999999975 WX7V/5 +1.1 19 1.000001120 WZ7I +0.6 1047 1.000000628 YO2CK* -0.2 2244 0.999999834 YO2MAX* +0.0 1906 1.000000024 ZL3X -0.2 116 0.999999815 ZL4YL +1.4 213 1.000001398 ZS1NN -4.7 16 0.999995292 Last updated 2025-05-07 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 0506 0505 0504 0503 0502 0501 0430 0429 0428 0427 --------------------------------------------------------------------- 2E0INH -0.1 3D2AG +0.5 +0.5 +0.1 +0.4 +0.1 +0.6 +0.7 +0.5 +1.0 +1.3 3V9A -0.9 -1.0 -1.5 -1.4 -1.3 -1.3 5Z4GO +0.8 +1.1 +0.2 +0.5 +0.0 +0.0 -0.3 +0.3 +1.0 7N4XCV +0.7 +0.3 +0.5 +0.4 +0.0 +0.4 +1.0 +0.1 +0.1 +0.5 AA0O +1.0 +0.0 +0.7 +0.3 +0.5 +1.0 AA4VV -9.9 AC0C-1 +0.1 +0.0 -0.3 +0.0 -0.2 +0.0 -0.1 +0.0 +0.0 BA6KC +0.1 +0.5 +0.1 -0.0 -0.1 -0.0 -0.0 +0.0 +0.0 +0.0 BD7JNA +0.0 -1.2 BD8CS +0.1 -0.0 +0.1 +0.0 +0.1 +0.1 BG0AJO/0 +0.0 -1.2 +0.1 +0.0 -0.1 +0.0 +0.0 +0.0 +0.0 +0.0 BG0AJO -0.1 -0.2 +0.4 +0.7 +0.3 +0.4 +0.2 +0.6 +0.7 +0.4 BG2TFW +8.4 +9.1 +9.2 +9.9 +8.8 +9.3 +9.2 +9.5 +8.9 +8.9 BG4GOV +0.0 +0.1 +0.3 +0.0 BH4RRG +0.0 +0.0 +0.2 +0.1 +0.4 +0.0 +0.2 +0.1 -0.1 +0.2 BH4RRG- +0.0 +3.2 BH4XDZ -1.3 +0.0 +0.2 +0.1 +0.0 -0.1 +0.7 +0.0 +0.2 +0.0 BI4MPH-1 +0.0 +0.0 +0.0 -0.0 +0.0 +0.0 +0.0 +0.0 +0.0 -0.1 BY4XRA -0.1 +0.0 +0.1 +0.2 +0.0 +0.1 +0.2 +0.0 +0.1 +0.1 CT1EYQ -0.1 -0.1 -0.3 -0.1 -0.0 -0.2 -0.2 -0.0 -0.3 -0.1 CX6VM +2.7 +1.7 +2.1 +2.3 +1.0 +0.8 +0.9 +0.9 +1.1 +1.4 DD0VS +16.1 DD5XX +0.7 +0.6 +1.1 +1.6 +1.4 +1.1 +1.1 +1.0 +1.1 +1.0 DE1LON +2.0 +2.0 +2.0 +2.7 +2.8 +2.6 +2.4 +1.8 +2.2 +2.3 DF2CK +1.5 +1.1 +1.4 +1.9 +1.5 +1.4 +1.3 +1.2 +1.1 +1.1 DF5EG -0.3 DF7GB +0.1 -0.1 -0.0 +0.0 -0.0 -0.0 +0.0 +0.0 +0.1 +0.0 DK0TE +0.8 +0.5 +2.0 +2.5 +1.8 +1.7 +1.7 +1.0 +1.0 +1.2 DK1MAX +0.0 DK3UA +0.4 -0.4 +1.2 +0.2 +0.1 +0.4 DK3WW +0.2 +0.2 -0.0 -0.1 +0.1 -0.1 -0.0 +0.2 +0.4 +0.3 DK8NE +0.0 +0.0 DK9IP +0.0 -0.1 -0.2 -0.0 -0.0 -0.0 -0.1 -0.1 -0.2 DK9IP-1 +0.0 -0.1 -0.1 -0.1 +0.0 +0.0 -0.1 -0.1 -0.1 DL0LA -0.0 -0.0 -0.1 -0.1 -0.1 -0.2 -0.1 -0.0 -0.1 -0.1 DL0PF +8.4 +9.4 +8.2 +8.3 +8.8 +9.2 +7.5 +8.5 +9.1 +8.3 DL1AMQ -1.2 DL1EFW +0.1 -0.4 DL1HWS +0.3 +0.2 +0.4 +0.4 +0.3 +0.3 +0.3 +0.2 +0.4 +0.5 DL1HWS-3 +0.6 +0.4 +0.6 +0.6 +0.5 +0.5 +0.6 +0.5 +0.7 +0.3 DL1HWS-4 +0.2 +0.2 +0.3 +0.4 +0.3 +0.3 +0.2 +0.0 +0.9 +0.7 DL3OBQ -7.4 -7.1 -9.9 DL4CF +0.0 +0.2 +0.0 DL5RCN +12.6 -0.3 +13.2 +12.6 +12.7 +12.6 +12.4 DL5RMH +0.1 +0.1 DL8LAS +0.3 +0.5 +0.5 +0.8 +0.9 DL8TG +0.0 +0.1 +0.0 -0.1 -0.0 +0.2 +0.1 DL9GTB -0.1 -0.3 +0.4 +0.8 +0.7 +0.9 +0.3 +0.3 +0.5 +0.6 DM5GG -0.2 +0.1 +0.4 +0.5 +0.4 +0.3 +0.2 +0.1 +0.3 +0.4 DM6EE +0.0 +0.1 +0.1 -1.4 +0.1 +0.1 DO4DXA +0.1 -0.0 -0.1 -0.0 +0.0 -0.0 -0.0 -0.1 +0.0 +0.0 DO4ZT +0.1 -0.0 -0.0 +0.0 -0.0 +0.0 +0.0 -0.0 +0.1 -0.0 DR4W -4.9 -4.9 -2.8 -2.6 -2.5 -2.7 -2.7 -3.2 -3.5 -4.8 E28AC +0.1 +0.0 -1.1 -0.9 -0.5 -0.2 -1.3 +3.4 +4.3 +4.4 EA1DIW +4.7 EA1RX +0.5 -1.4 +0.2 EA2CW +0.2 +0.3 +0.5 +0.6 +0.5 +0.3 +0.3 +0.1 +0.1 -0.1 EA2RCF-4 +0.4 +0.7 +0.8 +0.8 +0.5 +0.6 +0.7 +0.5 +0.8 +0.7 EA5RQ -0.3 -0.0 +0.0 -0.1 +0.0 -0.0 -0.1 -0.1 -0.0 +0.0 EA5RQ/A +0.0 +0.1 +0.0 +0.3 +0.3 EA5WU +0.0 +0.1 +0.0 -0.0 +0.1 +0.0 +0.0 -0.0 +0.2 +0.0 ES2RR -0.1 -0.0 -0.0 -0.0 -0.0 -0.1 -0.1 -0.0 +0.0 +0.0 ES5PC +0.0 +0.1 -0.0 +0.0 -0.0 +0.0 +0.0 -0.0 +0.0 +0.0 F4BPO -1.1 -0.8 -0.9 -0.6 -0.3 -0.3 -0.6 +0.0 -0.9 -1.1 F4GOU +5.1 +5.2 +6.0 +6.4 +6.0 +5.9 +5.6 +5.1 +4.9 +4.7 F4VVG -0.4 -0.3 +0.1 +0.1 -0.0 +0.2 +0.2 F5AHD +0.8 F5VLY +0.4 +0.1 +0.0 -0.1 +1.4 +0.5 F6IIT -1.0 -1.1 -0.7 -0.2 -0.3 -0.3 -0.1 -0.4 -0.4 -0.7 G0KTN +0.3 +0.3 +0.3 +0.5 +0.5 +0.5 +0.4 +0.4 +0.6 +0.5 G0TMX +0.1 G3XBI +0.2 +0.4 +0.4 +0.2 +0.1 +0.2 +0.1 -0.3 +0.2 +0.5 G3YPP +0.7 -1.0 +0.2 +0.0 -0.0 +1.1 +0.5 +0.1 +0.0 -0.0 G4IRN +0.6 +0.6 +0.6 +0.8 +0.6 +0.5 +0.6 +0.5 +0.7 +0.7 G4ZFE +0.2 +0.3 +0.5 +0.9 +0.8 +0.7 +0.7 +0.5 +0.7 +0.4 GI4DOH-2 +0.1 +0.0 +0.0 +0.0 +0.1 +0.3 +0.3 +0.2 +0.2 +0.2 GI4DOH-3 +0.5 +0.4 GX0FRE -0.0 -0.4 +0.4 +0.5 +0.1 +0.4 +0.6 +0.4 +0.4 HA1VHF +0.2 +0.5 +0.8 +1.0 +0.7 +0.5 +0.5 +0.2 +0.4 +0.2 HA6PX +0.1 -0.0 -0.0 -0.0 +0.0 +0.0 -0.0 +0.0 +0.1 -0.0 HA8TKS +0.3 +0.4 +0.3 +0.4 +0.3 +0.3 +0.4 +0.3 +0.4 +0.4 HB9BXE +0.2 -0.0 +0.1 +0.2 +0.1 -0.0 +0.0 +0.0 +0.2 +0.2 HB9DCO -0.2 -0.3 -0.4 -0.3 -0.2 -0.3 -0.1 -0.1 -0.1 -0.3 HB9GVO +0.7 +1.1 +0.5 +0.6 +0.0 +1.2 +0.7 +0.0 +0.8 +1.1 HG0Y +8.1 +8.0 +7.8 +7.7 +7.8 +7.5 +7.6 +7.4 HG8A +0.6 +0.8 +1.0 +1.0 +0.6 +0.7 +0.6 +0.4 +0.6 +0.7 IK3STG +1.2 +1.8 +2.0 +1.6 +1.9 +2.2 +1.9 +2.2 +2.3 IK4VET +4.1 +3.8 +4.2 +4.4 +3.9 +3.7 +3.9 +3.8 +3.8 +3.9 IK7YTT +0.0 +0.1 +0.0 +0.0 +0.0 -0.0 -0.0 -0.0 +0.0 -0.0 IT9GSF +0.7 +0.0 +0.8 +0.2 +0.2 +0.1 +0.3 +0.5 JG1DLY -1.3 -0.3 -0.4 -0.9 -0.8 JH4UTP +0.5 JH7CSU1 +4.8 +2.1 +1.4 +0.7 +0.8 +2.6 +1.4 +1.6 JI1HFJ +4.3 +4.0 -3.5 -3.7 -3.7 -0.2 -3.8 -1.9 -2.5 -2.3 JJ2VLY +14.8 +14.8 +14.9 +14.6 +14.8 +14.8 +14.6 +14.7 +14.7 JK1QLQ +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.1 JN1ILK -0.0 +0.1 +0.3 +0.2 -0.2 +0.3 -0.1 -0.4 +1.2 +1.4 K1RA +0.0 +0.7 +0.5 +0.5 +0.7 +0.1 +0.3 -0.2 K2PO/7 +0.6 +0.4 +0.5 +0.8 +0.2 +0.3 +0.6 +0.4 +0.4 +0.5 K3PA-1 +0.1 -0.1 -0.0 -0.2 +0.0 -0.1 -0.0 -0.1 -0.0 -0.0 K3PA-2 +0.0 -0.5 -0.3 -0.2 -0.4 +0.0 +0.0 -0.2 -0.2 K4PP +0.1 -0.2 -0.2 +0.2 +0.3 +0.2 +0.3 +0.2 +0.5 +0.2 K5EM +0.8 +0.5 +0.6 +0.8 +0.5 +0.8 +0.6 +0.5 +0.7 K5TR +0.8 +0.7 +0.7 +0.7 +0.3 +0.5 +0.8 +1.3 +0.6 +0.3 K6FOD +0.3 +0.0 +0.1 -0.0 -0.1 +0.1 -0.1 -0.0 -0.0 -0.0 K7CO -0.1 +0.3 +0.9 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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 OE9GHV WB6BEE Last updated 2025-05-07 00:15:32 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.