It's nice to promote CW, but that seems like an odd frequency choice. They say:
Six bands are to be used – 10, 15, 20, 40, 80 and 160m. Suggested frequencies are from 018 to 028 kHz up from band edges, plus or minus as activity dictates.
On upper bands 18-28 up from band bottom is mostly extra class, with only 3 kHz for other classes. 160 meters, 1820 to 1828 is commonly used for DX work. :-)
As for time:
Times: On the second and fourth Wednesday of each month at 1300 - 1400z (favoring Asia/Pacific); 1900 - 2000z (favoring Europe/Africa); and 0300 - 0400z –Thursday (Wednesday evening in US/Canada).
NOTE: See Scores Page for exact dates of CWT each month.
It doesn't look like it is more than 1 hour on Wednesdays. Maybe you are hearing something else? What time are you mobile??