Skimmer frequency accuracy
To be a good RBN citizen a skimmer should have a frequency accuracy of 2ppm or better.
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 here is based on archived RBN data from the previous day, 00:00 to 23:59 UTC. When making adjustments, this means that changes in calibration will not have full impact on the listed data until the second day after the change.
The deviation estimates listed below are based on spots on all active bands (40m and above) from the respective skimmer. If different hardware is used for different bands, the deviation number may thus not represent the actual deviation for a particular band.
The software used to calculate the tables below can be found here. It runs as a cron job in an Ubuntu container on my server and uploads to this WordPress site ten minutes after midnight UTC every night.
The calculation of deviation estimates 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 criterion of spots are outlined below.)
Repeating the analysis with this this extended set of skimmers as frequency reference drastically increases the geographical coverage of the algorithm, in turn increasing the number of qualifying spots, thus leading to 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 is 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.
Due to propagation characteristics, operator behavior (e.g. small QSY), and just statistical variations, 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.
1246893 RBN spots between 2021-04-11 00:00 and 23:59 UTC. 181043 spots (14.5%) were from reference skimmers (*). Average spot flow was 866 per minute from 181 active CW skimmers. 411090 spots from 177 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 ------------------------------------- 3B8CW +0.1 501 1.000000095 3D2AG -0.7 193 0.999999262 3V/KF5EYY +0.5 2957 1.000000512 5W1SA +0.7 259 1.000000734 9A1CIG +3.1 1592 1.000003116 9V1KB +0.0 157 1.000000045 9V1RM -0.5 436 0.999999524 AC0C-1* -0.0 1581 0.999999962 BA7KW +3.1 675 1.000003118 BA7QT +0.0 378 1.000000000 BD7JNA +0.1 379 1.000000132 BD7LMD -1.4 56 0.999998600 BD7MLA +1.6 1336 1.000001561 BD7NWR +14.9 51 1.000014945 BD8SZ +0.6 154 1.000000632 BG4GOV -0.1 555 0.999999922 BG8PA* -0.0 1005 0.999999964 BH4RRG +3.8 502 1.000003824 BH4RRG0 +1.3 450 1.000001315 BH4RRG1 +2.1 240 1.000002107 BH4XDZ +0.5 105 1.000000543 CT7ANO -0.2 4069 0.999999772 CX6VM* -0.1 1162 0.999999912 DD5XX +0.3 3315 1.000000276 DE1LON +0.5 5408 1.000000549 DF4XX -0.5 3516 0.999999543 DF5EG -2.1 451 0.999997945 DF7GB* -0.0 6394 0.999999962 DK0TE +2.6 5052 1.000002598 DK3UA -0.5 1272 0.999999525 DK9IP +0.1 4914 1.000000134 DL0LA +1.4 5522 1.000001383 DL0PF +1.2 6489 1.000001174 DL3DTH +0.3 6413 1.000000286 DL8LAS -4.2 4203 0.999995754 DL8TG -1.2 4238 0.999998800 DM6EE -3.5 1941 0.999996491 DM7EE +0.6 4693 1.000000559 DR4W +4.4 6737 1.000004398 E28AC -6.8 1849 0.999993237 EA1URA +1.6 5562 1.000001595 EA2NN* -0.1 748 0.999999867 EA5WU -0.7 4481 0.999999328 EA8BFK* +0.0 4808 1.000000015 ES5PC +0.7 2906 1.000000725 F4VSQ +4.6 1070 1.000004646 F5AHD +0.3 1385 1.000000260 F6IIT -0.9 7419 0.999999057 F8DGY -0.5 6906 0.999999461 G0TMX* +0.1 1164 1.000000082 G4HSO -0.2 2010 0.999999769 G4ZFE +0.2 4525 1.000000182 G5ROB +0.5 206 1.000000518 GI4DOH +2.7 1574 1.000002670 GM6DX +1.0 698 1.000000970 HA1VHF -0.1 6065 0.999999891 HA5PP +2.0 298 1.000001962 HA6PX +5.7 2928 1.000005722 HA7GN -0.3 2759 0.999999687 HA8TKS +0.7 2011 1.000000715 HB9BXE +0.3 503 1.000000298 HB9DCO -0.3 3426 0.999999725 HB9JCB +1.9 5612 1.000001851 HG8A -1.9 5487 0.999998133 IK3STG -0.9 3437 0.999999094 IK4VET-1 +0.5 7371 1.000000518 IZ2CPS -1.0 3633 0.999999024 JA4ZRK +0.3 260 1.000000291 JG1DLY -0.7 170 0.999999287 JG1VGX -1.6 77 0.999998412 JH7CSU1 +3.8 1551 1.000003815 JI1HFJ -7.4 691 0.999992575 JJ2VLY -1.4 1293 0.999998631 JQ1BVI -0.1 1291 0.999999934 JQ1YUF +0.1 1311 1.000000083 JR1BFZ/2 -0.4 352 0.999999605 K1FC -0.2 88 0.999999838 K1TTT* -0.1 1592 0.999999851 K2DB* +0.2 1193 1.000000190 K2PO/7 +0.6 1543 1.000000574 K3PA* +0.1 2172 1.000000055 K4BEN -14.2 823 0.999985765 K5TR +0.8 2242 1.000000765 K7EG +1.0 764 1.000000975 K7MJG* +0.1 544 1.000000066 K9IMM* +0.0 2267 1.000000023 K9LC +0.4 2267 1.000000367 K9TM-4 +0.7 2366 1.000000659 KC0VKN -0.4 252 0.999999558 KC4YVA +4.7 604 1.000004696 KD2OGR* -0.3 801 0.999999699 KD7YZ +0.3 2496 1.000000256 KH6LC -0.3 344 0.999999717 KL7RA +19.0 9 1.000019006 KM3T* +0.0 3993 1.000000035 KM3T-1* -0.1 630 0.999999932 KM3T-2 +0.7 4531 1.000000682 KO7SS +1.4 2239 1.000001371 KO7SS-7* +0.2 1743 1.000000153 KP2RUM* -0.1 1733 0.999999871 KQ8M +7.2 611 1.000007195 KU7T -0.4 1682 0.999999613 LZ3CB* +0.0 5216 1.000000034 LZ4AE* -0.0 6494 0.999999954 LZ4UX* +0.0 4000 1.000000012 MW0MUT +0.4 6040 1.000000426 N4TVC +0.3 1902 1.000000296 N4ZR/3 +0.2 2593 1.000000227 N6TV +0.3 877 1.000000263 N6WIN-7 -0.6 1217 0.999999423 N7TUG -0.1 314 0.999999909 NA0B +0.2 115 1.000000248 NC7J +0.6 1344 1.000000600 NN3RP -0.9 500 0.999999149 OE9GHV* +0.0 7065 1.000000049 OG73X +1.4 1532 1.000001423 OH6BG -1.9 378 0.999998135 OK2EW -0.7 12472 0.999999316 OL7M +1.7 5062 1.000001677 ON6ZQ +1.0 4295 1.000001021 PA0MBO +0.3 1991 1.000000263 PA3GRM +0.2 1578 1.000000230 PA5KT -1.1 1040 0.999998904 PJ2A -2.0 2234 0.999997977 R6YY +1.3 5299 1.000001297 RL3A-2 +1.9 2410 1.000001862 RN4WA -0.4 5699 0.999999618 RU9CZD +3.2 3302 1.000003233 S50ARX +0.6 1049 1.000000611 S53M -4.0 9 0.999996040 SJ2W +0.9 5174 1.000000928 SM0TCZ +2.2 871 1.000002233 SM6FMB* -0.1 4588 0.999999933 SM7IUN* +0.1 6114 1.000000132 SP5SR +0.6 570 1.000000575 SV8RV +3.1 4677 1.000003126 SZ1A -0.2 5074 0.999999820 TF3Y -0.5 3292 0.999999483 TF4X -1.9 8008 0.999998077 UA4M +5.1 333 1.000005096 UA9LIF +5.9 754 1.000005871 UY2RA +0.3 1950 1.000000321 V51YJ -1.7 163 0.999998252 VE2WU* +0.1 2082 1.000000062 VE6AO -1.4 530 0.999998602 VE6WZ +1.7 1680 1.000001651 VE7AB +1.1 180 1.000001148 VE7CC* -0.0 1596 0.999999991 VK2GEL +3.2 36 1.000003180 VK4CT -1.5 1510 0.999998487 VK6ANC -1.0 844 0.999999049 VU3KAZ +0.5 390 1.000000457 VY0ERC -1.0 14 0.999998982 W1NT-2 -1.1 3533 0.999998931 W1NT-6 -0.7 5142 0.999999332 W2AXR +0.6 2708 1.000000640 W2NAF +0.7 878 1.000000728 W3LPL +1.1 3104 1.000001085 W3OA* -0.1 165 0.999999914 W3RGA +0.3 2606 1.000000328 W4AX +3.6 477 1.000003646 W4KAZ -1.1 1685 0.999998862 W6YX +0.1 1190 1.000000079 W7HR +0.7 895 1.000000696 W8WWV +0.7 2548 1.000000698 W9XG +4.5 1074 1.000004491 WA7LNW -0.4 2178 0.999999554 WA9VEE +0.0 7 1.000000000 WB6BEE* -0.1 1991 0.999999892 WC2L +0.1 963 1.000000148 WE9V -0.6 2779 0.999999418 WS3W +0.5 2001 1.000000513 WZ7I* -0.1 4554 0.999999924 YL2SW* -0.1 5596 0.999999944 ZL2BR -13.6 164 0.999986448 ZL4YL +1.6 1611 1.000001579 ZS6BNE +1.5 58 1.000001473 Last updated 2021-04-12 00:10:43 UTC
Historical skimmer frequency accuracy
Below you will find historical accuracy data for the past five 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 21-04-11 21-04-10 21-04-09 21-04-08 21-04-07 ------------------------------------------------------------- 3B8CW +0.1 +0.4 -0.0 -0.1 +0.9 3D2AG -0.7 -0.7 +0.0 -1.3 +0.0 3V/KF5EYY +0.5 +0.3 +0.3 +0.1 +0.4 5W1SA +0.7 +0.4 +0.7 9A1CIG +3.1 +2.0 +1.5 +2.8 +1.6 9V1KB +0.0 +0.1 +0.0 9V1RM -0.5 -0.5 -0.4 +0.1 -1.0 AC0C-1 -0.0 -0.0 +0.1 -0.0 +0.0 BA7KW +3.1 +2.4 +2.3 +2.1 +3.5 BA7PC +0.8 +0.9 BA7QT +0.0 +0.0 +0.0 +0.0 +1.5 BD7JNA +0.1 +0.2 +13.0 -1.2 -4.6 BD7LMD -1.4 BD7MLA +1.6 +1.3 +1.1 +1.4 +1.8 BD7NWR +14.9 BD8SZ +0.6 +0.1 +0.0 BG2UKX +40.1 BG4GOV -0.1 -0.4 -0.7 -0.3 -1.7 BG8PA -0.0 +0.0 +0.1 +0.0 +0.1 BH1VCS +11.4 BH4RRG0 +1.3 BH4RRG1 +2.1 BH4RRG +3.8 -0.8 -2.5 -4.7 -6.8 BH4XDZ +0.5 +0.3 BY1CY +0.0 +0.0 CT7ANO -0.2 +0.2 +0.1 -0.2 -0.0 CX6VM -0.1 -0.1 +0.0 -0.0 -0.3 DD5XX +0.3 +0.2 +0.4 +0.2 +0.4 DE1LON +0.5 +0.2 -0.1 +0.0 +0.6 DF4XX -0.5 -0.2 +0.0 +0.2 -0.2 DF5EG -2.1 -2.1 DF7GB -0.0 -0.0 +0.1 -0.1 +0.0 DK0TE +2.6 +2.2 +1.8 +1.4 +1.5 DK3UA -0.5 -0.4 -0.2 -0.4 -0.2 DK9IP +0.1 +0.0 +0.1 +0.0 +0.1 DL0LA +1.4 +1.1 +0.7 +0.7 +1.0 DL0PF +1.2 +0.8 +0.7 +0.5 +0.7 DL3DTH +0.3 +0.1 +0.2 +0.1 +0.1 DL8LAS -4.2 -4.3 -4.2 -3.6 -3.5 DL8TG -1.2 -1.1 -0.8 -0.9 -1.0 DM6EE -3.5 -3.5 -2.0 -3.3 -2.8 DM7EE +0.6 +0.4 +0.4 +0.2 +0.3 DO4DXA -0.4 DR4W +4.4 +3.5 +2.4 +1.6 +1.8 E28AC -6.8 -8.7 -8.8 -8.7 -7.6 EA1URA +1.6 +1.3 +1.3 +1.2 +1.4 EA2NN -0.1 +0.0 EA5WU -0.7 -0.7 -0.7 -0.8 -0.5 EA8BFK +0.0 -0.0 -0.1 -0.1 +0.0 ES3V -1.8 -1.7 ES5PC +0.7 +0.9 +0.0 +0.2 +0.4 ET3AA +0.4 +0.3 +0.8 F4VSQ +4.6 +2.8 +8.0 +9.5 +4.9 F5AHD +0.3 +0.2 -0.7 -1.2 F6IIT -0.9 -0.8 -0.6 -0.8 -0.9 F8DGY -0.5 -1.1 -3.5 +0.1 -1.6 G0TMX +0.1 G4AON +1.0 +0.9 +1.1 G4HSO -0.2 -0.6 -1.1 -0.6 +0.0 G4ZFE +0.2 +0.1 +0.2 +0.1 +0.1 G5ROB +0.5 +0.7 +1.2 +0.0 GI4DOH +2.7 +0.5 +0.2 +0.1 +0.0 GM6DX +1.0 +0.6 +0.8 +0.7 +0.4 HA1VHF -0.1 -0.2 -0.5 -0.6 -0.4 HA5PP +2.0 HA6PX +5.7 +3.9 +2.0 +1.3 +2.5 HA7GN -0.3 -0.6 -0.7 -0.9 -0.8 HA8TKS +0.7 +0.4 +0.3 +0.1 +0.3 HB9BXE +0.3 +0.5 +0.7 +0.3 +0.6 HB9DCO -0.3 -0.1 -0.1 +0.0 +0.1 HB9JCB +1.9 +1.6 +1.2 +1.2 +1.3 HG8A -1.9 -1.2 -1.0 -0.7 -0.7 IK3STG -0.9 -1.0 -1.0 -1.2 -1.2 IK4VET-1 +0.5 +0.6 +0.7 +0.3 +0.1 IZ2CPS -1.0 -0.9 -1.0 -0.9 -0.9 JA4ZRK +0.3 -0.2 +0.0 +0.6 -0.4 JG1DLY -0.7 +0.2 JG1VGX -1.6 -1.3 JH7CSU1 +3.8 +3.1 +3.0 +2.0 +3.5 JI1HFJ -7.4 -8.8 -4.8 JJ2VLY -1.4 -1.4 -1.6 -1.6 -1.0 JQ1BVI -0.1 -0.2 -0.3 +0.2 +0.6 JQ1YUF +0.1 -0.9 -1.4 -1.1 -1.9 JR1BFZ/2 -0.4 -0.3 -0.1 +0.3 -1.0 K1FC -0.2 -0.5 +0.0 -3.3 K1TTT -0.1 -0.2 -0.4 -0.3 -0.1 K2DB +0.2 -0.1 +0.0 -1.8 -2.1 K2PO/7 +0.6 +0.4 +0.5 +0.4 +0.6 K3PA +0.1 -0.1 +0.0 +0.2 +0.0 K4BEN -14.2 -14.1 -14.8 K5TR +0.8 +0.7 +1.0 +1.0 +0.8 K7EG +1.0 +0.7 +0.9 +1.2 +1.5 K7MJG +0.1 +0.1 +0.2 +0.3 +0.2 K9IMM +0.0 -0.1 -0.1 +0.0 +0.2 K9LC +0.4 +0.2 +0.3 +0.1 +0.5 K9TM-4 +0.7 +0.3 +0.3 +0.5 +0.7 KC0VKN -0.4 -1.0 -0.3 -0.2 +0.4 KC4YVA +4.7 +4.9 +4.0 +3.5 +5.3 KD2OGR -0.3 -0.7 -0.2 -0.2 -0.2 KD7YZ +0.3 +0.3 +0.1 +0.1 +0.2 KH6LC -0.3 +0.1 +0.0 +0.0 -0.5 KI4PAD +0.0 KL7RA +19.0 +2.9 KM3T +0.0 -0.1 -0.0 -0.0 +0.0 KM3T-1 -0.1 +0.1 +0.1 +0.4 +0.1 KM3T-2 +0.7 +0.6 +0.5 +0.6 +0.4 KO7SS +1.4 +1.1 +1.3 +1.3 +1.0 KO7SS-7 +0.2 +0.0 +0.3 +0.3 -0.0 KP2RUM -0.1 -0.1 -0.3 -0.1 -0.1 KQ8M +7.2 +8.0 +7.0 +9.1 +7.6 KU7T -0.4 -0.5 -0.3 -0.3 -0.3 LA6TPA +0.1 +0.5 LZ3CB +0.0 +0.0 +0.1 -0.0 -0.1 LZ4AE -0.0 -0.3 -0.1 -0.2 -0.1 LZ4UX +0.0 -0.0 +0.0 +0.0 +0.1 MW0MUT +0.4 +0.5 +0.5 +0.5 +0.2 N0OI +4.7 +3.3 +4.3 N4TVC +0.3 +0.1 +0.5 +0.4 +0.3 N4ZR/3 +0.2 +0.1 -0.2 -0.1 -0.0 N6TV +0.3 +0.1 +0.4 +0.5 +0.3 N6WIN-7 -0.6 -0.8 -0.3 -0.7 -0.4 N7TUG -0.1 +0.4 +1.0 -0.0 +1.1 NA0B +0.2 +0.4 +0.0 +0.0 +0.3 NC7J +0.6 +0.5 NN3RP -0.9 -1.0 -0.2 -1.3 -1.4 OE6ADD +1.1 +0.8 +1.1 OE9GHV +0.0 -0.1 +0.1 -0.0 -0.1 OG73X +1.4 +1.1 OH6BG -1.9 -1.8 -1.8 OK2EW -0.7 -0.7 -0.6 -0.7 -0.6 OL7M +1.7 +0.2 -0.3 -0.4 -0.1 ON6ZQ +1.0 +1.0 +0.7 +0.6 +1.1 PA0MBO +0.3 +0.3 +0.2 +0.0 +0.2 PA3GRM +0.2 +0.1 PA5KT -1.1 -1.6 +0.0 PJ2A -2.0 -1.7 -1.2 -1.5 -1.6 R6YY +1.3 +1.1 +1.1 +0.8 +1.0 RK3TD +0.0 +0.1 RL3A-2 +1.9 +0.9 +0.5 +0.2 +0.5 RN4WA -0.4 -0.3 -0.4 -0.5 -0.2 RU9CZD +3.2 +2.4 +2.2 +1.6 +2.0 S50ARX +0.6 +1.0 +0.3 +0.4 -0.2 S53M -4.0 SJ2W +0.9 +0.7 +0.6 +0.6 +0.8 SM0TCZ +2.2 +1.7 +1.6 +1.3 +1.6 SM6FMB -0.1 +0.0 +0.1 +0.0 -0.0 SM7IUN +0.1 -0.0 +0.1 -0.0 +0.2 SP5SR +0.6 +0.5 +0.1 +0.2 +0.8 SV8RV +3.1 +2.9 +2.6 +2.6 +2.9 SZ1A -0.2 -0.5 -0.6 -0.5 -0.2 TF3Y -0.5 -0.3 -0.4 -0.5 -0.3 TF4X -1.9 -1.9 -1.7 -2.1 -1.8 UA4M +5.1 +3.9 +3.9 +3.9 +4.1 UA9LIF +5.9 +5.4 UR6EA -0.8 UY2RA +0.3 +0.3 +0.4 +0.3 +0.3 V51YJ -1.7 -3.3 -2.8 -2.8 -2.1 VE2WU +0.1 -0.2 -0.2 -0.3 -0.1 VE6AO -1.4 -0.8 -1.0 -0.4 -1.3 VE6WZ +1.7 +1.5 +1.4 +1.7 +1.7 VE7AB +1.1 +0.2 +1.5 +1.8 +2.9 VE7CC -0.0 +0.1 +0.0 +0.2 +0.0 VK2GEL +3.2 +5.3 +1.2 +3.0 +0.0 VK3RASA -12.0 -6.7 -9.4 VK4CT -1.5 -0.8 -0.9 -0.5 -1.0 VK6ANC -1.0 -0.5 -1.3 -0.1 -1.1 VU3KAZ +0.5 -0.4 +0.0 -1.1 VY0ERC -1.0 -1.4 -4.1 W1NT-2 -1.1 -1.1 -0.9 -0.9 -1.1 W1NT-6 -0.7 -0.7 -0.6 -0.7 -0.8 W2AXR +0.6 +0.6 W2NAF +0.7 W3LPL +1.1 +0.9 +0.9 +0.9 +1.2 W3OA -0.1 +0.0 W3RGA +0.3 +0.2 +0.2 +0.5 +0.2 W3UA +2.8 W4AX +3.6 +3.6 +3.7 +2.7 +4.1 W4KAZ -1.1 -1.2 -0.9 -1.2 -1.4 W6YX +0.1 +0.1 +0.1 +0.2 +0.3 W7HR +0.7 +0.7 +0.6 +1.3 +1.0 W8WWV +0.7 +0.7 +0.7 +0.6 +0.8 W9XG +4.5 +4.1 +4.6 +4.8 +4.5 WA7LNW -0.4 -0.5 -0.3 -0.6 -0.5 WA9VEE +0.0 +0.0 -0.6 +0.0 -1.0 WB6BEE -0.1 -0.1 -0.1 +0.1 -0.0 WC2L +0.1 +0.1 -0.2 -0.0 -0.0 WE9V -0.6 -0.8 -0.3 WS3W +0.5 +0.1 +0.3 -0.1 +0.7 WZ7I -0.1 -0.1 +0.1 -0.0 -0.0 YL2SW -0.1 +6.4 +12.7 ZL2BR -13.6 -14.1 -14.9 -14.7 -13.2 ZL3X +1.6 +5.4 ZL4YL +1.6 +1.4 +0.9 +1.1 +1.1 ZS6BNE +1.5 +2.3 Last updated 2021-04-12 00:11:04 UTC
Activity statistics
Summary of unique calls spotted and active skimmers per band and continent.
RBN activity between 2021-04-11 00:00 and 23:59 UTC.
1246893 spots with 13775 unique callsigns from 189 active skimmers.
Unique callsigns spotted per continent and band
---------------------------------------------------------------
160m 80m 60m 40m 30m 20m 17m 15m 12m 10m 6m
AF 7 33 0 104 10 74 16 13 2 7 0 198
AS 59 320 2 1014 136 813 99 309 13 101 37 1968
EU 386 2349 165 3230 1166 2807 324 352 10 57 25 7266
NA 143 842 31 2027 430 1667 171 198 16 82 10 3773
OC 10 30 0 155 30 133 10 87 4 26 0 348
SA 1 15 0 74 16 90 32 51 5 20 0 222
606 3589 198 6604 1788 5584 652 1010 50 293 72
Active skimmers per continent and band
---------------------------------------------------------------
160m 80m 60m 40m 30m 20m 17m 15m 12m 10m 6m
AF 3 3 1 5 4 4 4 4 3 4 0 5
AS 17 22 0 26 17 28 14 28 12 20 6 29
EU 61 68 21 73 57 73 43 54 5 21 6 80
NA 42 51 14 59 44 54 36 47 9 24 6 62
OC 5 7 0 10 7 10 6 8 2 4 0 10
SA 2 2 0 2 2 2 2 2 1 1 0 3
130 153 36 175 131 171 105 143 32 74 18
Last updated 2021-04-12 00:12:53 UTC