[en] The antenna of the KSTAR ICRF heating system was newly fabricated, which has many enhanced aspects in comparison with the prototype antenna. RF test for the modified antenna was performed without any cooling of the antenna during RF test campaign-5. The maximum standoff voltage was estimated through the RF tests and antenna performance was tested during 300-sec long pulse test. A bottom half of the current strap-1 was connected to the test section with an electrical length of 20 m which is equal to two times of the wave length at a frequency of 30 MHz. So a standing wave was generated on the test section. As a result, the maximum standoff voltage was 40.0 kVp at a pulse length of 5 sec. It was limited by a breakdown on the teflon insulator used in transmission line. Long pulse test showed the maximum standoff voltage was 24.3 kVp at a pulse length of 300 sec. It was limited by overheating of the antenna. It was confirmed that it is impossible to increase available voltage at 300-sec long pulse operation without any cooling. It means that active cooling of the antenna is necessary to increase the standoff voltage. During this test campaign, a range of multifactor discharge was experimentally determined, and conditioning effect was estimated