Under Indonesia broadcast regulation, the frequencies FM 107.7MHz, FM 107.8MHz and FM 107.9MHz are only used for low power radio broadcast (community and campus radio stations)

In Indonesia, the broadcast regulation authority, known as KPI (Komisi Penyiaran Indonesia) or Indonesia Broadcasting Commission had regulated that the frequency slot FM 107.7MHz, FM 107.8MHz and FM 107.9MHz as low power radio transmission for community and campus radio broadcasters in the country since 2002.

Unlike Malaysia where FM 107.7MHz is allowed to be used for higher power radio transmission (eg: Negeri FM Gunung Ledang 1kW), I checked all frequency spectrum list of Indonesia radio stations from FM 107.7MHz to 107.9MHz, most of the radio stations transmitter power are not more than 0.05kW (50W).

The main reason of Indonesia radio stations (notably high power radio transmission) are not allowed to allocate on 107.7, 107.8 and 107.9 is because interference to airband.

The frequency after FM 107.5MHz are actually nearby airband (VHF 108-137MHz). In Indonesia, many aviation transmissions are occupying the frequency within 108-130MHz.

The interference from radio broadcast on those frequencies (107.7, 107.8 and 107.9) can led flight incident in Indonesia because signal of 107.7, 107.8 and 107.9 leaked to airband frequency. In addition, as KPI has reserved these frequency for community radio stations, if one of radio station operates on these frequencies on high power transmission, it can cause interference to other community radio stations, alongside the airband.

Under the regulation of Indonesia Broadcasting Commission (KPI- Komisi Penyiaran Indonesia), the radio stations which use FM 107.7MHz, FM 107.8MHz and FM 107.9MHz have to follow the transmission criteria below:

1. Maximum antenna height: 20 meters

2. Maximum transmitter power: 50 watts (50W)

3. Maximum transmission distance: 2.5 kilometers per radius

The Indonesia radio frequency regulation of FM 107.7MHz-107.9MHz is same with Australia frequency regulation where FM 87.5MHz-FM 88.0MHz are reserved for low power radio stations (also known as narrowcast).

Previously I had received Radio Jawa/Raja FM 107.7MHz from Medan, Indonesia in several Malaysia locations such as Bagan Datuk, Teluk Intan and Kinta Highlands, despite Radio Raja FM 107.7MHz is low power community radio station in Medan, but I received it in Malaysia under tropospheric propagation.