I see the original poster has their location listed as Korea. The sats that I gave as examples are not visible from there.
If the OP can find a sat of interest to them with a rated EIRP of 48 or above at their location, an 18 or 22 inch dish may give some usable results, but bad weather will probably cause loss of signal lock. If you have a 24 inch dish and an EIRP of 49 or above, you should do okay in most weather. This is based on my own hands-on experience and testing.
Here in North America, a 30-inch or larger dish is needed for reliable, usable reception of most Ku Linear FTA satellites. It may be different in Korea.
There have been several threads on this forum, including one started by me, concerning the use of surplus 18- 22 inch dishes for linear Ku FTA use. Try the search feature to find more detailed information in those older threads.
Here is a link to my earlier post with detailed 22" dish info:
http://www.satelliteguys.us/free-air-fta-discussion/209227-what-can-i-get-linear-lnb.html
Hope this helps.