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
350695 RBN spots between 2025-03-25 00:00 and 23:59 UTC. 123405 spots (35.2%) were from reference skimmers (*). Average spot flow was 244 per minute from 210 active CW skimmers. 189836 spots from 205 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 ------------------------------------- 3B8GL +0.0 12 1.000000000 3D2AG +0.1 75 1.000000095 3V9A -2.0 163 0.999998031 5Z4GO +0.4 9 1.000000446 7N4XCV +0.7 42 1.000000708 AA0O +0.1 75 1.000000063 AC0C-1 -0.1 345 0.999999853 BD8CS -0.0 163 0.999999978 BG0AJO +0.2 58 1.000000157 BG0AJO/0 -0.0 201 0.999999956 BG2TFW +10.7 89 1.000010726 BH4RRG +0.2 50 1.000000214 BH4XDZ -0.1 60 0.999999940 BI4MPH-1 -0.0 55 1.000000000 BY4XRA +0.2 50 1.000000214 CT1EYQ -0.9 144 0.999999075 CX6VM +2.6 96 1.000002563 DC8YZ* +0.0 2365 1.000000017 DD5XX +0.5 1572 1.000000501 DE1LON +1.3 687 1.000001283 DF2CK +1.1 3602 1.000001067 DF7GB* +0.0 1814 1.000000043 DK0TE +0.9 1892 1.000000870 DK1MAX +0.0 7 1.000000000 DK3UA -0.7 409 0.999999257 DK9IP* -0.1 1265 0.999999891 DK9IP-1 -0.1 1643 0.999999904 DL0LA -0.3 870 0.999999711 DL0PF +4.7 2616 1.000004656 DL1HWS* +0.0 1595 1.000000013 DL1HWS-3 +0.3 930 1.000000270 DL1HWS-4 -0.0 357 0.999999962 DL5RCN +12.6 599 1.000012595 DL8LAS +0.5 1282 1.000000474 DL9GTB +0.9 1892 1.000000909 DM5GG +1.4 2611 1.000001370 DM6EE* -0.1 2012 0.999999943 DO4DXA* -0.1 2156 0.999999872 DO4ZT* -0.0 1540 0.999999973 DR4W -2.6 926 0.999997445 E28AC +5.9 201 1.000005907 EA1RX +0.0 9 1.000000000 EA2CW* -0.1 1745 0.999999875 EA2RCF-4 +0.1 1314 1.000000149 EA5RQ -0.0 246 0.999999952 EA5WU* -0.0 2127 0.999999963 ES2RR* -0.0 1967 0.999999971 ES5PC* -0.1 2531 0.999999928 ET3AA -11.0 138 0.999989032 F4GOU +5.0 2043 1.000005023 F4VVG* -0.1 1095 0.999999926 F6KGL* +0.1 1750 1.000000142 G0KTN +0.1 1953 1.000000148 G3XBI +0.2 527 1.000000189 G3YPP -6.6 187 0.999993429 G4IRN +0.4 2712 1.000000433 G4ZFE +0.3 1885 1.000000275 GE0FRE -0.5 109 0.999999542 GI4DOH-2 +0.2 1828 1.000000209 GI4DOH-3* +0.1 559 1.000000057 GX0FRE* -0.2 999 0.999999845 HA1VHF +1.5 2205 1.000001495 HA6PX* -0.1 1883 0.999999949 HA8TKS* +0.2 1190 1.000000165 HB9BXE +0.2 1717 1.000000212 HB9DCO* -0.1 1455 0.999999906 HB9GVO +0.5 90 1.000000474 HG0Y +6.9 432 1.000006897 HG8A* +0.1 2110 1.000000068 IK3STG +2.4 1899 1.000002386 IK7YTT* -0.0 690 0.999999967 JH7CSU1 +1.8 103 1.000001802 JI1HFJ -2.4 37 0.999997635 JJ2VLY +14.1 85 1.000014102 JK1QLQ +0.0 9 1.000000000 JN1ILK +5.0 317 1.000005005 K1RA -0.5 1280 0.999999509 K2PO/7 +0.2 833 1.000000243 K3PA-1 +0.0 482 1.000000033 K3PA-2 +0.2 150 1.000000220 K4PP +0.3 892 1.000000340 K5EM +0.3 69 1.000000327 K5TR +0.3 1604 1.000000335 K6FOD -0.1 465 0.999999861 K7CO +2.5 543 1.000002481 K7EK -0.2 246 0.999999783 K9IMM* +0.0 1099 1.000000026 K9LC +0.4 1130 1.000000409 K9QC -0.2 374 0.999999848 KA7OEI +0.2 444 1.000000173 KD2OGR +0.3 698 1.000000314 KH6LC +0.4 157 1.000000430 KM3T-2* -0.1 883 0.999999863 KM3T-3* -0.0 1714 0.999999999 KM3T-5* -0.1 922 0.999999931 KO7SS +0.2 460 1.000000203 KP2RUM +0.6 1321 1.000000556 KP3CW* -0.0 755 0.999999980 KV4TT* +0.0 1230 1.000000050 LA6TPA -2.3 668 0.999997680 LA7GIA -0.1 102 0.999999906 LB9KJ* +0.1 546 1.000000134 LZ3CB* -0.1 969 0.999999866 LZ4AE -0.4 1987 0.999999638 LZ4UX* -0.0 1507 0.999999955 LZ5DI +0.8 2117 1.000000768 LZ7AA +0.5 1259 1.000000513 M0ORD -0.8 2475 0.999999204 MM0ZBH +0.6 2469 1.000000615 N2CR -0.2 738 0.999999811 N6TV +0.6 512 1.000000615 N8DXE +1.2 455 1.000001157 N9CO* -0.1 1051 0.999999883 NG7M -0.2 616 0.999999841 NN3RP +0.5 235 1.000000471 NT6Q -3.9 790 0.999996087 NU4F* -0.0 1506 0.999999996 OE3KLU +7.1 55 1.000007066 OE6TZE* -0.1 775 0.999999883 OG66X* +0.1 548 1.000000113 OH4KA +0.1 307 1.000000064 OH6BG -0.5 2059 0.999999520 OH8KA +4.2 1471 1.000004161 OK1FCJ +0.1 1817 1.000000147 OK1HRA -4.2 1876 0.999995776 ON6ZQ -0.4 1609 0.999999594 OZ1AAB* +0.1 529 1.000000108 OZ1BZS +0.4 331 1.000000359 OZ4ADX +0.1 289 1.000000110 PA0MBO +0.3 625 1.000000300 PA2SQ +0.6 111 1.000000634 PE5TT* -0.0 1576 0.999999993 PI4CC +0.6 2028 1.000000561 R1LB +0.9 594 1.000000900 R9IR* +0.1 546 1.000000074 RK3TD +0.1 1372 1.000000148 RK3TD-2* +0.0 1602 1.000000028 RN4WA +0.8 1324 1.000000807 RU9CZD +0.2 1214 1.000000168 S50ARX +0.2 1926 1.000000169 S50U +0.2 896 1.000000182 S53A* -0.0 2421 0.999999952 S53F* +0.2 631 1.000000211 S53WW -0.4 2062 0.999999605 SE5E* +0.1 2240 1.000000117 SM0TCZ +1.4 49 1.000001383 SM1HEV* +0.2 1841 1.000000158 SM7IUN -0.1 1047 0.999999882 SQ5J +9.2 848 1.000009250 SQ5OUO +7.5 77 1.000007455 SV1CDN +0.2 62 1.000000173 SZ1A* -0.0 1819 0.999999973 TF3Y +1.6 1060 1.000001556 TI7W* +0.0 1499 1.000000034 UA0S +3.7 575 1.000003740 UA4CC +13.3 691 1.000013306 UD4FD +0.4 377 1.000000383 UT5R -0.5 285 0.999999525 UY2RA +6.1 170 1.000006118 V51YJ +2.9 53 1.000002893 VE3EID +0.1 1871 1.000000088 VE6AO -1.5 173 0.999998538 VE6JY +1.0 881 1.000001016 VE6WZ +3.3 772 1.000003337 VE7CC +0.8 492 1.000000750 VK2GEL +0.7 148 1.000000745 VK2RH +1.1 20 1.000001070 VK3FFB +2.1 5 1.000002121 VK3RASA +0.0 61 1.000000000 VK6ANC +0.1 93 1.000000115 VR2FUN-77* +0.2 808 1.000000155 VU2CPL +0.3 70 1.000000319 VU2PTT +0.3 156 1.000000259 VU2TUM +7.4 79 1.000007357 W1NT-2* -0.1 1590 0.999999942 W1NT-6* +0.0 1736 1.000000002 W2MV +0.3 189 1.000000301 W2NAF +1.1 1000 1.000001055 W3DAN +1.3 445 1.000001343 W3LPL -1.5 97 0.999998459 W3OA +0.4 159 1.000000375 W3OA-1 +0.0 8 1.000000000 W3RGA -0.1 347 0.999999877 W3UA* -0.0 1644 0.999999953 W4AX +4.2 76 1.000004234 W4KAZ -1.0 1013 0.999999001 W6YX* +0.2 729 1.000000234 W8WTS -0.4 887 0.999999627 W8WWV -1.4 1247 0.999998615 WA7LNW +0.8 1273 1.000000770 WB6BEE* +0.0 1072 1.000000022 WC2L* +0.1 772 1.000000114 WC8GOP +7.6 70 1.000007594 WE9V +0.1 1062 1.000000058 WS2C +4.5 972 1.000004464 WT9U +0.5 199 1.000000536 WV4P* +0.0 841 1.000000010 WX7V/5 +0.0 72 1.000000000 WZ7I* +0.1 2225 1.000000072 YO2CK +0.8 2225 1.000000799 YO2MAX* +0.1 2230 1.000000114 YO5LD +0.4 1843 1.000000398 ZL3X +0.0 252 1.000000039 ZL4YL +1.2 327 1.000001186 ZS1NN -4.4 78 0.999995555 Last updated 2025-03-26 00:15:33 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 0325 0324 0323 0322 0321 0320 0319 0318 0317 0316 --------------------------------------------------------------------- 2E0INH +4.3 3B8GL +0.0 +0.0 +0.4 +0.0 +0.0 +0.0 +0.7 +0.4 +0.5 3D2AG +0.1 +0.2 +0.3 +1.0 +0.8 +0.9 +0.8 +0.8 +0.9 +1.2 3V9A -2.0 -1.5 -1.7 -1.6 -1.8 -2.1 5Z4GO +0.4 +0.7 +0.6 +0.9 +0.3 +0.3 +0.0 +0.0 +1.8 +0.8 7N4XCV +0.7 +0.5 +0.6 +2.9 +0.7 +1.4 +0.7 +1.3 +1.6 +1.3 AA0O +0.1 +0.5 +0.1 +0.5 +0.6 +0.7 +0.5 +0.3 +0.3 AC0C-1 -0.1 -0.1 +0.0 +0.1 +0.0 -0.2 +0.1 -0.0 +0.1 +0.1 BA6KC +0.2 +0.1 -0.1 BD7JNA -0.1 BD8CS -0.0 -0.2 -0.0 -0.1 -0.0 +0.1 +0.1 -0.2 -0.0 +0.0 BG0AJO/0 -0.0 +0.0 -0.1 -0.1 -0.1 +0.1 -0.0 -0.0 -0.0 +0.0 BG0AJO +0.2 +0.1 +0.6 +0.6 +0.3 +0.3 +0.1 -0.0 +0.1 +0.5 BG2TFW +10.7 +10.8 +10.0 +10.8 +11.0 +11.3 +11.0 +10.9 +11.5 +10.7 BG4GOV +0.6 BH4RRG +0.2 -0.1 +0.2 +0.7 +0.0 +0.0 +0.0 +0.0 +0.2 +0.2 BH4XDZ -0.1 -0.1 -0.1 -0.3 +0.0 +0.2 +0.1 +0.1 +0.1 -0.0 BI4MPH-1 -0.0 +0.0 +0.4 +0.4 -0.0 +0.0 +0.0 +0.0 +0.1 +0.1 BY4XRA +0.2 +0.1 -0.1 +0.3 +0.1 +0.4 +0.1 +0.0 +0.1 +0.2 CN3A +0.5 +0.1 CT1EYQ -0.9 -0.9 -0.9 -1.3 -0.9 -0.8 -0.4 -0.7 -0.7 -1.1 CX6VM +2.6 +3.2 +3.3 +2.9 +3.3 +3.4 +3.3 +2.4 +3.4 +1.4 DC8YZ +0.0 +0.0 +0.0 +0.1 +0.0 +0.1 +0.0 +0.1 +0.1 +0.1 DD5XX +0.5 +0.5 +0.5 +0.9 +0.8 +0.6 +0.1 -0.2 -0.2 -0.4 DE1LON +1.3 +1.6 +1.3 +2.0 +1.7 +1.6 +1.5 +1.0 +1.4 +1.8 DF2CK +1.1 +1.1 +1.0 +1.4 +1.2 +1.0 +0.7 +0.3 +0.5 +0.4 DF2JP +2.1 DF7GB +0.0 -0.1 +0.0 +0.0 -0.0 +0.0 -0.0 -0.1 +0.1 +0.0 DK0KK -6.4 DK0TE +0.9 +0.6 +0.8 +1.1 +0.5 +0.6 +0.4 +0.6 +0.5 +0.5 DK1MAX +0.0 -0.1 +0.0 +0.0 -0.1 DK3UA -0.7 -1.0 -0.7 -0.8 +2.9 DK3WW +0.0 -0.1 -0.1 -0.1 +0.0 -0.1 DK8NE +0.0 DK9IP -0.1 -0.1 -0.1 -0.2 -0.1 -0.1 -0.1 -0.1 -0.1 -0.2 DK9IP-1 -0.1 -0.2 -0.2 -0.2 -0.2 -0.9 -0.2 -0.2 -0.2 -0.2 DL0LA -0.3 -0.2 -0.1 -0.2 -0.2 -0.0 -0.2 -0.2 -0.1 -0.2 DL0PF +4.7 +5.0 +5.4 +4.7 +4.4 +4.7 +4.5 +4.2 +4.4 +4.4 DL1HWS +0.0 +0.1 -0.0 +0.1 +0.1 +0.2 +0.2 +0.2 +0.1 +0.1 DL1HWS-3 +0.3 +0.2 +0.4 +0.4 +0.2 +0.2 +0.4 +0.6 DL1HWS-4 -0.0 +0.0 +0.0 -0.1 +0.3 +0.5 +0.3 +0.1 +0.1 DL5RCN +12.6 +12.6 +12.4 +11.8 +12.4 +11.8 +12.3 DL6ZB +0.2 DL8LAS +0.5 +0.5 +0.5 +0.7 +0.8 +0.5 +0.4 +0.4 +0.3 +0.4 DL8TG -0.2 -0.1 -0.1 -0.2 DL9GTB +0.9 +1.1 +0.4 +0.6 +0.5 +0.9 +0.8 +0.9 DM5GG +1.4 +1.0 +1.1 +0.3 +0.2 +0.2 +0.1 +0.2 +0.2 +0.4 DM6EE -0.1 +0.1 +0.0 -0.0 +0.0 -0.0 +0.1 +0.0 +0.1 -0.0 DO4DXA -0.1 +0.0 -0.0 -0.0 +0.0 -0.1 DO4ZT -0.0 -0.1 -0.0 -0.1 -0.1 +0.0 -0.0 -0.1 -0.1 -0.0 DP7D +0.3 +0.5 +0.6 +0.2 +0.3 -0.0 -0.0 -0.1 +0.1 DR4W -2.6 -2.8 -2.4 -2.7 -2.7 -3.0 -2.9 -3.6 -2.2 -3.1 DXSDR +0.1 -0.1 +0.0 -0.3 E28AC +5.9 +4.8 +5.1 +4.2 +5.5 +4.9 +4.2 +5.8 +5.8 +4.0 EA1RX +0.0 -0.4 -0.4 -0.7 -1.7 -1.6 -1.2 EA2CW -0.1 -0.1 -0.1 +0.1 +0.1 +0.1 +0.0 +0.0 +0.1 -0.1 EA2RCF-4 +0.1 +0.2 +0.2 +0.2 +0.2 +0.3 +0.2 +0.2 +0.3 +0.3 EA5RQ -0.0 +0.0 -0.0 -0.0 +0.1 +0.0 -0.3 -0.1 +0.1 +0.1 EA5RQ/A +0.0 -0.1 +0.2 +0.3 +0.0 +0.0 +0.2 EA5WU -0.0 -0.0 -0.0 -0.0 -0.0 -0.0 +0.0 +0.0 +0.2 +0.0 EI6LF +0.0 ES2RR -0.0 +0.0 -0.1 -0.1 -0.1 -0.1 -0.0 -0.0 -0.0 +0.0 ES5PC -0.1 +0.0 -0.0 +0.0 -0.1 -0.0 +0.0 +0.0 ET3AA -11.0 -11.1 -13.7 -11.5 -12.2 F4GOU +5.0 +4.7 +5.0 +5.7 +5.4 +5.1 +5.1 +5.1 +5.1 +5.9 F4VVG -0.1 -0.0 +0.0 +0.1 -0.0 -0.2 +0.0 +0.1 +0.1 +0.3 F6KGL +0.1 +0.3 -0.1 G0KTN +0.1 +0.2 +0.1 +0.2 +0.1 +0.2 +0.0 +0.0 -0.0 -0.1 G0TMX +0.2 +0.3 G3XBI +0.2 +0.3 +0.3 +0.2 +0.4 G3YPP -6.6 -2.0 +0.0 +0.0 +0.2 +0.0 -0.1 +0.0 +0.1 +0.0 G4IRN +0.4 +0.5 +0.4 +0.7 +0.5 +0.5 +0.4 +0.4 +0.4 +0.4 G4ZFE +0.3 +0.5 +0.3 +0.6 +0.6 +0.6 +0.4 +0.2 +0.4 +0.2 GE0FRE -0.5 -0.2 -0.2 -0.6 +0.3 -0.4 -0.5 -0.5 GI4DOH-2 +0.2 +0.4 +0.2 +0.3 +0.1 -0.0 +0.0 +0.2 +0.1 -0.0 GI4DOH-3 +0.1 -0.1 -0.0 +0.1 -0.0 -0.3 -0.3 -0.1 +0.0 -0.3 GX0FRE -0.2 -0.1 +0.0 -0.1 +0.0 -0.2 -0.3 -0.2 -0.0 +0.3 HA1VHF +1.5 +1.5 +1.1 +1.3 +1.0 +0.9 +0.7 +0.8 +1.0 +1.6 HA5PP +0.5 +0.0 HA6PX -0.1 +0.1 -0.1 -0.1 -0.0 +0.0 -0.0 -0.0 -0.0 +0.0 HA8TKS +0.2 +0.3 +0.2 +0.4 +0.3 +0.4 +0.2 +0.3 +0.4 +0.5 HB9BXE +0.2 +0.3 +0.2 +0.3 +0.1 +0.2 +0.3 +0.1 +0.3 +0.3 HB9DCO -0.1 -0.1 -0.1 -0.2 -0.2 -0.2 -0.3 -0.3 -0.2 -0.3 HB9GVO +0.5 +1.1 +0.8 +0.7 +0.4 +1.0 +0.8 +0.7 +0.7 +0.3 HG0Y +6.9 +6.6 +6.8 +6.6 +6.7 +6.6 +6.6 HG8A +0.1 +0.3 -0.2 -0.3 -0.1 -0.2 -0.1 +0.0 -0.1 -0.3 IK3STG +2.4 +2.6 +2.2 +2.9 +2.6 +2.6 +2.2 +2.4 +2.5 +3.1 IK4VET +2.7 +1.6 +2.0 +1.7 +1.9 +1.4 +1.6 +2.3 +2.3 IK7YTT -0.0 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 -0.1 +0.0 -0.0 IU0MVD +0.4 J68HZ +17.8 JG1DLY -1.6 -0.9 -0.6 -0.2 JH4UTP +0.6 JH7CSU1 +1.8 +1.9 +1.8 +1.9 +1.9 +2.2 +2.0 +2.0 +2.5 +2.7 JI1HFJ -2.4 -0.9 -4.9 -3.9 -2.7 -7.7 -5.2 -1.3 -4.5 -0.2 JJ2VLY +14.1 +14.1 +14.2 JK1QLQ +0.0 +0.0 +0.6 +0.0 +0.2 +0.3 -1.1 +0.0 +0.2 +0.2 JN1ILK +5.0 +3.1 +2.3 +3.7 +0.7 K1RA -0.5 -0.3 -0.8 -0.7 -1.5 -0.1 -0.1 -1.1 -1.0 +0.1 K2PO/7 +0.2 +0.3 +0.2 +0.2 +0.1 +0.3 +0.6 +0.3 +0.6 +0.4 K3PA-1 +0.0 +0.1 -0.1 -0.0 +0.0 +0.1 +0.1 -0.1 +0.1 +0.0 K3PA-2 +0.2 +0.1 +0.2 +0.3 +0.2 +0.3 +0.6 +0.2 +1.3 +15.2 K4PP +0.3 +0.3 +0.2 +0.3 -0.1 +0.3 +0.3 +0.0 -0.2 +0.6 K5EM +0.3 +0.4 +0.7 +0.5 +0.6 +0.4 +0.7 +0.4 +0.7 +0.5 K5TR +0.3 +0.3 +0.4 +0.2 +0.2 +0.1 +0.5 +0.4 +0.7 +0.3 K6FOD -0.1 -0.2 -0.1 -0.1 -0.4 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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 WB6BEE Last updated 2025-03-26 00:15:41 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.