My ICOM IC-820H, which I'm currently using, seems to have extremely poor UHF reception sensitivity.
Even with Satellite ISS and SO-50 FM repeaters, reception is almost impossible.
YC8RPK Loland pointed out that my signal was coming in strongly but I wasn't responding when he called, which made me realize the problem.
So I tried replacing just the receiver in my Quansheng UV-K5 handheld transceiver.
As a result, I was able to make contact with YF8YO via the ISS voice repeater.
YC8WAB recorded the QSO and sent it to me.
Several other stations were calling, but I couldn't receive their signals.
Mount Malindang, located at an altitude of 2400mH, is about 30km west of
my house.
Therefore, the direction from west to northwest from my house is unfavorable for satellite communications.
However, according to ChatGPT, satellites are visible if the elevation angle is 5 degrees or more.