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
224175 RBN spots between 2024-07-26 00:00 and 23:59 UTC. 63927 spots (28.5%) were from reference skimmers (*). Average spot flow was 156 per minute from 172 active CW skimmers. 106190 spots from 169 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 1101 0.999999935 3D2AG -0.3 56 0.999999675 7N4XCV +1.5 34 1.000001539 9M2CNC +0.5 192 1.000000520 AA0O -8.1 297 0.999991903 AC0C-1 -0.1 814 0.999999889 BA6KC -0.3 134 0.999999734 BD4QJP -0.6 34 0.999999418 BD7JNA -0.5 57 0.999999499 BD8CS -0.1 333 0.999999864 BG2TFW -7.7 30 0.999992314 BG4GOV +0.4 35 1.000000408 BH4RRG +0.0 38 1.000000000 BH4RXP -0.1 133 0.999999857 BH4XDZ -0.1 38 0.999999875 BI4MPH-1 -0.1 41 0.999999913 BI4RFP-YZ +0.0 76 1.000000031 BI4SSB +0.1 34 1.000000140 CX6VM +1.2 12 1.000001188 DC8YZ* +0.0 2018 1.000000004 DD5XX* -0.1 1334 0.999999908 DE1LON +1.1 1188 1.000001112 DF2CK +1.2 2776 1.000001154 DF7GB* -0.0 1271 0.999999974 DJ2BC* -0.1 1405 0.999999874 DJ9IE* -0.1 539 0.999999911 DK0TE +2.8 1220 1.000002816 DK3UA -8.7 611 0.999991339 DK9IP* +0.1 858 1.000000108 DK9IP-1 +0.1 1189 1.000000101 DL0LA +0.4 633 1.000000437 DL0PF +1.4 1427 1.000001365 DL1HWS +0.1 1621 1.000000075 DL5RCN +12.4 915 1.000012385 DL8LAS +0.2 2287 1.000000188 DL8TG* +0.0 1522 1.000000023 DL9GTB -0.2 605 0.999999798 DM5GG +0.4 2210 1.000000363 DR4W -1.1 758 0.999998894 EA1URA +0.4 939 1.000000390 EA2CW +0.5 948 1.000000483 EA5RQ +0.3 373 1.000000344 EA5WU -0.1 1162 0.999999856 EA7/VE3NZ -0.3 214 0.999999667 ES2RR* -0.1 749 0.999999939 F4VVG* -0.1 645 0.999999912 F5AHD +1.3 333 1.000001284 G0KTN +0.1 940 1.000000130 G3XBI +0.1 218 1.000000082 G3YPP +0.3 26 1.000000274 G4IRN +0.2 876 1.000000228 G4ZFE +0.3 1598 1.000000333 GI4DOH +4.6 326 1.000004581 HA1VHF -0.1 264 0.999999900 HA6PX* -0.1 1579 0.999999935 HA8TKS +0.2 1071 1.000000163 HB9BXE* +0.2 1309 1.000000197 HB9DCO* +0.0 1151 1.000000015 HG0Y +7.9 93 1.000007893 HG8A +2.6 1546 1.000002568 IK4VET +3.7 1749 1.000003717 JH4UTP +0.7 42 1.000000679 JH7CSU1 +0.4 72 1.000000380 JI1HFJ +3.2 19 1.000003209 JJ2VLY +1.7 122 1.000001669 JN1ILK +0.5 319 1.000000509 K3PA-1* -0.2 429 0.999999821 K4PP -0.2 292 0.999999848 K5TR +0.9 280 1.000000854 K6FOD +0.0 158 1.000000045 K7CO +0.7 86 1.000000746 K7EK +0.1 150 1.000000142 K7MJG +0.4 67 1.000000360 K9IMM +0.1 653 1.000000079 K9LC +0.3 587 1.000000277 KA7OEI +0.3 175 1.000000258 KC4YVA +6.0 159 1.000005984 KD2OGR +0.2 237 1.000000167 KH6LC +0.0 55 1.000000000 KM3T -0.1 513 0.999999880 KM3T-2 +0.7 940 1.000000718 KM3T-3* -0.0 648 1.000000000 KO7SS +0.7 408 1.000000653 KP3CW +0.2 438 1.000000157 KV4TT* +0.0 571 1.000000035 LA6TPA -0.1 464 0.999999863 LA7GIA -1.0 7 0.999998982 LB9KJ* +0.0 410 1.000000035 LZ3CB -1.3 54 0.999998710 LZ4AE* +0.0 622 1.000000031 LZ4UX* +0.0 973 1.000000022 LZ5DI -0.3 1419 0.999999747 LZ7AA +0.6 1045 1.000000602 MM0ZBH +0.8 1492 1.000000781 MM3NDH* +0.0 1931 1.000000049 MM3NDH-2* -0.0 1466 0.999999954 MM3NDH-3* +0.1 619 1.000000069 MW0MUT* -0.0 1585 0.999999985 N4ZR -1.7 386 0.999998345 N6TV +0.7 219 1.000000710 N7TUG +16.4 62 1.000016378 N9CO* -0.1 504 0.999999868 NG7M -0.2 261 0.999999824 NT6Q +16.9 152 1.000016939 OE6TZE* -0.0 1116 0.999999955 OE9GHV* -0.0 1701 0.999999965 OH6BG* +0.1 1034 1.000000113 OK1FCJ* +0.1 1838 1.000000075 OK1HRA -4.0 1505 0.999995971 OK4QRO +1.7 1379 1.000001673 ON6ZQ +0.4 1022 1.000000372 OZ1BZS +0.0 234 1.000000030 OZ4ADX* -0.0 620 0.999999992 PD0WAG +0.3 42 1.000000339 PE5TT +0.9 1049 1.000000884 R1LB +1.8 460 1.000001766 R6YY +0.2 311 1.000000214 RK3TD* +0.1 1377 1.000000097 RN4WA -7.7 878 0.999992256 RU9CZD -5.7 1036 0.999994256 S50U* +0.1 583 1.000000086 S53A +0.8 2284 1.000000821 S53WW +0.6 1391 1.000000557 SM0TCZ +1.0 79 1.000000990 SM1HEV* +0.0 435 1.000000038 SM7IUN* -0.0 1494 0.999999961 SQ5J +7.6 789 1.000007569 SQ5OUO +4.7 231 1.000004683 SV1CDN +1.0 218 1.000000981 SV1DPJ +0.2 454 1.000000189 SV8RV +9.2 116 1.000009212 SZ1A -1.3 587 0.999998705 TF3Y +1.1 773 1.000001081 TI7W -0.3 740 0.999999712 UA0S* -0.1 403 0.999999890 UA4CC +10.3 57 1.000010255 UA4M +3.4 296 1.000003445 UT5R +1.9 47 1.000001888 V51YJ +1.6 12 1.000001583 VE3EID* -0.0 769 0.999999979 VE6AO -0.3 75 0.999999683 VE6JY +2.0 442 1.000002029 VE6WZ -7.1 363 0.999992947 VE7CC +1.2 67 1.000001218 VK2RH +0.0 15 1.000000000 VK3RASA -2.2 22 0.999997804 VK6ANC -2.1 94 0.999997949 VR2FUN-77* +0.2 564 1.000000224 VU2CPL +4.4 75 1.000004371 W1NT-2 +0.8 708 1.000000761 W1NT-6 +0.7 558 1.000000742 W2MV +0.7 59 1.000000722 W2NAF +1.1 434 1.000001132 W3LPL -2.7 98 0.999997290 W3OA -0.0 638 1.000000000 W4AX +3.9 45 1.000003924 W6YX +0.5 403 1.000000485 W8WWV -1.5 557 0.999998456 WA7LNW +0.6 618 1.000000577 WB6BEE +0.0 87 1.000000000 WC2L +0.2 556 1.000000152 WE9V +0.1 674 1.000000142 WZ7I +0.1 780 1.000000149 YO4RDW -10.0 99 0.999989994 ZF1A +1.1 427 1.000001121 ZF9CW +0.6 960 1.000000592 ZL3X -1.4 227 0.999998577 ZL4YL +0.7 92 1.000000681 ZS1NN -3.9 10 0.999996117 Last updated 2024-07-27 00:15:21 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 0726 0725 0724 0723 0722 0721 0720 0719 0718 0717 --------------------------------------------------------------------- 2E0INH -0.1 +0.0 +0.0 -0.1 -0.1 -0.1 -0.1 +0.1 -0.0 -0.0 3D2AG -0.3 -0.1 -0.1 +0.0 +0.1 -0.1 -0.1 +0.1 -0.1 +0.1 7N4XCV +1.5 +0.9 +0.6 +0.3 +0.4 +0.5 +0.9 +1.7 +0.6 +1.5 9M2CNC +0.5 +0.4 +0.4 +0.3 +0.6 +0.9 +0.6 +1.0 +1.1 +1.2 AA0O -8.1 -7.9 -7.3 -8.4 -7.4 -9.7 -7.0 -7.7 -6.7 AC0C-1 -0.1 -0.1 -0.1 -0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.1 BA6KC -0.3 +0.0 -0.0 +0.0 +0.0 -0.1 -0.0 -0.1 -0.1 -0.1 BD4QJP -0.6 +0.2 +0.1 +0.0 +0.6 +0.0 +0.1 +0.1 +0.2 +0.2 BD7JNA -0.5 -0.1 +0.3 +0.3 BD8CS -0.1 +0.1 -0.1 -0.1 +0.1 BG0AJO +0.0 +0.1 +0.0 +0.1 +0.2 +0.1 -0.3 -0.1 -0.0 BG2TFW -7.7 -7.2 -6.9 -7.3 -7.3 -4.4 -5.6 -5.9 -5.9 -7.6 BG4GOV +0.4 +0.0 +0.1 +0.0 -0.3 +0.1 +0.3 +0.5 -0.1 BH4RRG +0.0 +0.1 +0.1 +0.0 +0.0 -0.0 +0.1 +0.1 +0.0 -0.2 BH4RXP -0.1 -0.2 -0.0 -0.2 +0.1 -0.1 -0.1 -0.1 +0.1 -0.2 BH4XDZ -0.1 +0.0 +0.3 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 BI4MPH-1 -0.1 +0.0 +0.1 +0.0 +0.0 +0.0 +0.1 +0.0 +0.3 +0.0 BI4RFP-YZ +0.0 +0.1 +0.1 +0.0 +0.1 +0.1 +0.2 +0.1 -0.2 BI4SSB +0.1 +0.0 +0.2 +0.1 +0.2 +0.1 +0.3 +0.3 +0.1 +0.3 CX6VM +1.2 +1.2 +0.7 +0.4 +1.0 +0.6 +0.6 +0.7 +0.3 DC8YZ +0.0 +0.0 +0.2 -0.0 +0.1 +0.0 +0.1 +0.1 -0.0 +0.0 DD5XX -0.1 -0.4 -0.4 -0.2 +0.2 +0.2 +0.7 +0.5 +0.5 +0.5 DE1LON +1.1 +1.4 +1.4 +1.1 +1.5 +1.5 +1.8 +1.1 +1.1 +1.0 DF2CK +1.2 +1.7 +1.5 +1.6 +1.9 +1.4 +1.6 +1.6 +1.3 +1.3 DF7GB -0.0 -0.0 +0.1 +0.0 -0.0 -0.0 -0.0 -0.0 -0.0 -0.1 DJ2BC -0.1 -0.2 +0.0 -0.1 +0.1 +0.0 -0.0 -0.1 -0.2 -0.0 DJ3AK -0.5 -0.3 DJ9IE -0.1 -1.9 +0.0 +0.0 -0.1 -0.0 +0.0 DK0TE +2.8 +3.0 +2.9 +2.4 +2.0 +4.0 +3.8 +3.2 +2.5 +1.2 DK3UA -8.7 -7.8 -7.9 -8.6 -7.7 -6.7 -7.9 DK8NE +0.1 +0.3 -2.7 +0.0 -0.6 -8.6 DK9IP +0.1 +0.3 +0.1 +0.1 +0.3 +0.1 +0.2 +0.1 +0.0 +0.1 DK9IP-1 +0.1 +0.4 +0.3 +0.2 +0.4 +0.2 +0.3 +0.2 +0.1 +0.2 DL0LA +0.4 +0.5 +0.5 +0.3 +0.4 +0.4 +0.5 +0.3 +0.2 +0.3 DL0PF +1.4 +1.9 +1.9 +1.6 +2.1 +2.2 +2.1 +1.9 +2.1 +1.9 DL1EFW +1.7 +1.6 DL1HWS +0.1 +0.3 +0.2 +0.2 +0.2 +0.2 +0.3 +0.2 +0.2 +0.2 DL5RCN +12.4 +12.0 +12.7 +12.9 +12.7 +12.0 +1.7 DL8LAS +0.2 +0.4 +0.3 +0.2 +0.5 +0.5 +0.4 +0.2 +0.1 +0.2 DL8TG +0.0 -0.1 +0.0 -0.1 -0.0 -0.1 +0.0 -0.0 -0.0 -0.0 DL9GTB -0.2 +0.1 +0.9 +0.1 +0.7 -2.5 -1.5 +9.4 -0.7 -3.0 DM5GG +0.4 +0.3 +0.5 +0.2 +0.4 +0.2 +0.4 +0.4 +0.3 +0.4 DM6EE +0.1 +0.1 +0.0 +0.0 DM7EE +0.4 DR4W -1.1 -2.1 -1.8 -1.3 -0.6 -1.0 -1.4 -1.2 -1.8 -1.9 EA1URA +0.4 +0.6 +0.5 +0.4 +0.5 +0.4 +0.8 +0.7 +0.6 +0.6 EA2CW +0.5 +0.7 +0.7 +0.5 +0.6 +0.4 +0.9 +0.7 +0.7 +0.7 EA4FIT +0.0 +0.0 EA5RQ +0.3 +0.4 +0.2 +0.1 +0.4 +0.3 +0.2 +0.4 +0.3 +0.4 EA5WU -0.1 -0.1 +0.1 -0.0 -0.1 +0.0 +0.0 -0.0 -0.0 -0.0 EA7/VE3NZ -0.3 -0.2 -0.0 -0.1 -0.1 -0.4 ES2RR -0.1 -0.1 -0.1 -0.1 -0.1 -0.0 +0.0 -0.1 -0.1 -0.1 ET3AA -13.7 -13.6 F4VVG -0.1 +0.2 +0.1 -0.1 -0.2 -0.3 -0.2 -0.2 -0.1 +0.0 F5AHD +1.3 +0.0 F6KGL -0.0 +0.1 +0.2 +0.2 G0KTN +0.1 +0.3 +0.0 +0.2 +0.3 +0.4 +0.3 +0.2 +0.1 +0.2 G0TMX +0.3 -0.2 +0.2 G0TTV +1.4 G3XBI +0.1 -0.1 -0.0 +0.0 +0.0 G3YPP +0.3 +0.3 +0.1 +0.4 +0.4 +0.1 +0.2 -0.1 -0.1 +0.0 G4IRN +0.2 +0.4 +0.2 +0.2 +0.4 +0.5 +0.6 +0.4 +0.4 +0.7 G4ZFE +0.3 +0.5 +0.5 +0.2 +0.6 +0.4 +0.7 +0.6 +0.3 +0.3 G4ZFE-1 +0.3 +2.2 +6.6 GI4DOH +4.6 +6.7 +9.2 +0.0 +0.2 +0.9 HA1VHF -0.1 +0.4 +0.5 +0.3 +0.4 +0.4 +0.3 +0.5 +0.5 +0.5 HA6PX -0.1 -0.1 -0.0 -0.1 -0.0 -0.1 -0.0 -0.0 -0.1 -0.1 HA8TKS +0.2 +0.3 +0.3 +0.1 +0.3 +0.2 +0.4 +0.2 +0.2 +0.3 HB9BXE +0.2 +0.4 +0.4 +0.2 +0.3 +0.3 +0.4 +0.2 +0.2 +0.2 HB9DCO +0.0 -0.3 +0.4 +0.1 +0.1 +0.1 -0.1 -0.2 HG0Y +7.9 +8.0 +7.9 +7.8 +8.1 +7.9 +8.0 +8.1 HG8A +2.6 +3.3 +3.4 +3.5 +4.1 +4.2 +4.4 +4.5 +4.6 +4.3 IK4VET +3.7 +4.0 +3.7 +3.9 +4.1 +4.0 +4.2 +4.2 +4.0 +3.5 JH4UTP +0.7 JH7CSU1 +0.4 +0.1 +0.0 +0.2 +0.3 +0.4 +0.2 +0.2 +0.2 JI1HFJ +3.2 -2.3 -5.2 -4.7 -3.0 -1.2 -2.8 -1.5 -1.8 -3.8 JJ2VLY +1.7 +2.6 +2.6 +1.1 +2.3 +2.6 +4.4 +3.4 +2.0 +2.2 JN1ILK +0.5 +0.4 +0.3 +0.3 +0.4 +0.5 +0.6 +0.4 +0.5 +0.4 K2PO/7 +0.5 +0.8 +0.6 +0.7 +0.4 +0.6 +0.9 K3PA-1 -0.2 -0.0 -0.0 -0.2 +0.0 -0.0 +0.0 +0.0 -0.1 -0.0 K4PP -0.2 -0.0 +0.0 +0.0 -0.1 -0.1 -0.1 -0.2 +0.1 K5TR +0.9 +1.0 +1.7 +1.7 +1.3 +1.2 +1.2 K6FOD +0.0 +0.1 +0.2 +0.0 -0.0 +0.2 +0.1 +0.1 +0.1 +0.2 K7CO +0.7 +1.9 +0.8 +1.0 +1.0 +0.9 +1.0 +0.5 +0.9 +0.6 K7EK +0.1 +0.1 -0.2 +0.0 -0.0 +0.0 +0.0 +0.0 -0.0 +0.1 K7MJG +0.4 +0.3 +0.2 +0.4 +0.1 +0.0 +0.0 +0.4 +0.0 K9IMM +0.1 -0.0 -0.0 -0.0 +0.1 +0.0 +0.0 +0.0 +0.0 +0.0 K9LC +0.3 +0.3 +0.4 +0.2 +0.4 +0.3 +0.4 +0.3 +0.3 +0.3 KA7OEI +0.3 +0.4 +0.2 +0.1 +0.2 +0.2 +0.2 +0.3 +0.0 +0.5 KC4YVA +6.0 +5.8 +5.6 +5.3 +5.3 +5.0 +5.0 +5.4 +5.7 +5.7 KD2OGR +0.2 +0.4 +0.1 +0.8 KH6LC +0.0 +0.1 -0.2 +0.1 +0.1 -0.1 +0.2 +0.1 +0.1 +0.1 KM3T -0.1 -0.1 -0.2 -0.1 -0.0 -0.1 -0.0 -0.1 -0.2 -0.1 KM3T-2 +0.7 +0.9 +0.7 +0.6 +0.6 +0.6 +0.8 +0.6 +0.7 +0.9 KM3T-3 -0.0 -0.0 -0.0 -0.1 -0.1 -0.0 +0.0 +0.0 -0.0 -0.1 KO7SS +0.7 +1.0 +0.8 +0.5 +0.5 +0.8 +0.9 +0.6 +0.9 +0.8 KP3CW +0.2 +0.1 +0.1 -0.1 +0.1 +0.2 +0.2 -0.0 +0.2 +0.3 KV4TT +0.0 +0.2 +0.2 +0.0 +0.1 +0.1 +0.2 +0.1 +0.0 +0.1 LA6TPA -0.1 -0.2 -0.4 -0.3 +1.6 +1.3 -0.2 -0.5 -0.1 +0.6 LA7GIA -1.0 -0.1 +0.2 -0.7 -0.1 -0.1 -0.1 LB9KJ +0.0 -0.1 -0.2 LU8XW -1.1 -0.3 +0.0 +0.0 -0.2 -0.5 +0.0 -0.7 LY3G +0.5 LZ3CB -1.3 -0.1 -0.1 +0.0 -0.1 -0.1 -0.1 -0.0 -0.1 -0.1 LZ4AE +0.0 -0.0 +0.1 +0.0 +0.2 +0.1 -0.0 +0.0 +0.0 +0.0 LZ4UX +0.0 +0.0 +0.0 -0.1 -0.3 -0.2 -0.1 -0.1 -0.0 -0.0 LZ5DI -0.3 -0.4 -0.2 +0.0 +0.3 +0.3 +0.5 +0.5 +0.4 +1.4 LZ7AA +0.6 +0.9 +0.7 +0.5 +1.0 +0.7 +0.9 +0.8 +0.6 +0.6 MM0ZBH +0.8 -0.5 +0.3 -0.4 -1.1 -0.4 +1.6 +1.4 +1.1 +1.2 MM3NDH +0.0 +0.0 +0.1 +0.0 +0.1 +0.0 +0.1 +0.0 +0.0 +0.0 MM3NDH-2 -0.0 +0.0 -0.0 -0.0 +0.0 -0.0 -0.0 -0.0 -0.1 -0.1 MM3NDH-3 +0.1 +0.2 +0.1 -0.0 -0.0 +0.0 +0.0 +0.0 -0.0 -0.0 MW0MUT -0.0 +0.1 -0.1 -0.0 +0.0 -0.0 +0.0 -0.1 -0.0 +0.1 N0OI +1.1 +1.0 +1.0 +0.6 +0.9 +0.8 N2QT +1.4 +1.4 +2.1 +1.6 N4ZR -1.7 -3.3 -2.6 -2.7 -2.6 N5ZO +5.3 +4.3 +5.9 +5.2 +5.7 +4.8 +5.5 +5.7 N6TV +0.7 +0.5 +0.4 +0.5 +0.6 +0.6 +0.6 +0.5 +0.5 +0.7 N7TUG +16.4 +15.7 +15.4 +15.2 +15.0 +15.1 +15.2 +14.9 +15.3 +15.6 N9CO -0.1 +0.1 +0.0 +0.0 +0.3 +0.2 NG7M -0.2 -0.1 -0.2 -0.1 -0.0 -0.2 -0.1 -0.1 -0.2 -0.0 NN3RP 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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 LZ4UX MM3NDH OE9GHV WB6BEE Last updated 2024-07-27 00:15:25 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.