Raaga FM 99.3MHz co-channel self interference detected in Taiping, Perak

According to this video, a YouTuber known as Kason Kong received FM 99.3MHz in Taiping, Perak. In this video, actually we can hear a lot of edge sound on FM 99.3MHz. It is Raaga (formerly known as THR Raaga), the edge sound from same station on a frequency is not known as co-channel interference (CCI), technically it is a self co-channel interference.

Co-channel interference is two different radio stations interfere each other on a same frequency, but "self co-channel interference" is two same radio stations interfere each other on a same frequency. The listening impact is less on "self co-channel interference" than co-channel interference because listeners are able to listen to the radio station under same station interference, but the impact can be reduced with a proper broadcast transmission timing. Double edge sound is occurred when the transmission timing has 0.5-1 seconds different.

The self interference between Raaga same stations on FM 99.3MHz is come from two different transmission site, Bukit Penara (for Penang) and Gunung Ulu Kali (Klang Valley, large parts of Pahang and South Perak). 

99.3MHz: Raaga Gunung Ulu Kali
99.3MHz: Raaga Bukit Penara

Apart from Raaga same station on FM 99.3MHz, there is also self co-channel interference stations such as:

1. IKIM FM 102.7MHz (Bukit Genting and Gunung Kledang)
2. One FM 88.1MHz (Gunung Ulu Kali and Gunung Ledang)

For IKIM FM case study, FM 102.7MHz in Bukit Genting is for Balik Pulau, and Teluk Kumbar only, meanwhile Gunung Kledang is for Central Perak. Meanwhile One FM 88.1MHz Gunung Ulu Kali is for Klang Valley and Gunung Kledang is for Melaka/North Johor, but as One FM Seremban frequency 88.3MHz is restricted only in Seremban, Negeri Sembilan (from Bukit Gan), the rest of Negeri Sembilan areas must tune to 88.1MHz, just there is self interference between Gunung Ulu Kali and Gunung Ledang, the listeners impact is not serious.

In Taiping, Raaga frequency is FM 102.1MHz from Bukit Larut, meanwhile 102.4MHz Gunung Jerai is still receivable.