Это виновата солнечная интерференция.
http://www.satellite-calculations.com/S ... UNcalc.htm
Выбираем Сириус 2, антенна - 115см. город Киев
Predicted Outage| Start    | End           | Duration| Start       | End
Date                  | UTC      | UTC          |             | CETWinter| CETWinter
mm/dd/yyyy      |hh:mm:ss| hh:mm:ss|mm:ss   | hh:mm:ss| hh:mm:ss  
--------------------|-----------|------------|-----------|------------|------------ 
02/27/2005       | 12:02:01 | 12:05:56 | 03:55    | 13:02:01 | 13:05:56
02/28/2005       | 12:00:13 | 12:07:23 | 07:10    | 13:00:13 | 13:07:23
03/01/2005       | 11:59:28 | 12:07:43 | 08:15    | 12:59:28 | 13:07:43
03/02/2005       | 11:59:16 | 12:07:31 | 08:15    | 12:59:16 | 13:07:31
03/03/2005       | 11:59:48 | 12:06:38 | 06:50    | 12:59:48 | 13:06:38
03/04/2005       | 12:01:31 | 12:04:26 | 02:55    | 13:01:31 | 13:04:26