Hat Yai is considered as Southern Thailand version of Bangkok in terms of FM radio stations frequency spectrum traffic condition because the frequency spectrum is quite peak in Hat Yai due to growing of community and commercial radio stations, alongside public broadcasters such as Radio Thailand, MCOT, Parliament Channel, Royal Thai Army, Air Force, Navy and Prince of Songkhla University.
However, I already noticed that Sunshine Radio Hat Yai was ceased since 2016, alongside recent defunct Sunshine Radio station in Phuket. In addition, according to Asiawaves.net, FM 102.75MHz was previously carried by Workers' Radio in Hat Yai, but it is INACTIVE.
In facts, FM 102.75MHz is now a vacant frequency in Hat Yai, Thailand, meanwhile Your FM 102.5MHz also broadcasts in Hat Yai as low power narrowcast community radio station. By referring Bangkok FM radio frequency spectrum condition, the main transmitter site radio stations separated at 500kHz, meanwhile the frequency separation between main radio stations and narrowcast radio stations is 250kHz.
Example: FM 92.5MHz, FM 92.75MHz and FM 93.0MHz
FM 92.5MHz is Radio Thailand national network, then FM 93.0MHz is Cool Fahrenheit 93 (under Voice of Navy), so separation is 500kHz. Between FM 92.5MHz and FM 93.0MHz, the frequency FM 92.75MHz is used as narrowcast broadcast stations such as: Sathani Witthayu Khon Charoen Nakhon {สถานีวิทยุคนเจริญนคร}, Sathani Witthayu Medee (Global Medee) {สถานีวิทยุมีดี (โกลบอลมีดี)}, and Sathani Witthayu Krachaisiang Phuea Phraputthasasana Haeng Chat lae Sangkhom {สถานีวิทยุกระจายเสียงพระพุทธศาสนาแห่งชาติและสังคม}, these 3 radio stations on FM 92.75MHz operate at very low power transmission, so they're considered as narrowcast.
For Hat Yai site, FM 102.75MHz is not a problem to be used in Khao Kho Hong as it has 500kHz frequency separation from Radio Thailand Songkhla FM 102.25MHz which is transmitted in same location, meanwhile Your FM 102.5MHz is transmitted from Tambon Hat Yai as low power community radio station to cover the sub-district only.
While FM 102.75MHz is suitable to be used in Khao Kho Hong, but to prevent interference to Your FM 102.5MHz, it is recommended to use low power transmitter there as much 50W. In addition, interference to border region (Malaysia) must be considered. Hence, I will issue RF analysis and tentative parameter of FM 102.75MHz for Khao Kho Hong transmission to cover Hat Yai.
In Khao Kho Hong, there are about 3 tower locations.
1. MCOT Songkhla FM 96.5MHz tower (low peak)
2. Air Force & Radio Thailand Songkhla transmission tower (upper peak)
3. Hat Yai Municipal Park side top peak
==Tentative parameter of FM 102.75MHz Hat Yai==
* Frequency: FM 102.75MHz
* Power: 50W
* Example antenna model: SIRA FM-04 3 bay array dipole antenna
* Antenna type: Dipole antenna
* Antenna polarization: Vertical
* Antenna gain: 6.0dBd
* ERP: 200W
==RF analysis==
102.5MHz: Your FM Hat Yai
102.75MHz: Khao Kho Hong, Hat Yai (50W)
<250kHz, OK>
102.7MHz: Nasional FM UUM Sintok
102.75MHz: Khao Kho Hong, Hat Yai (50W)
<50kHz, OK>
102.75MHz: Khao Kho Hong, Hat Yai (50W)
102.9MHz: Perlis FM Padang Pauh
<150kHz, OK>
102.25MHz: Radio Thailand Songkhla
102.75MHz: Khao Kho Hong, Hat Yai (50W)
<250kHz, OK>
102.75MHz: Khao Kho Hong, Hat Yai (50W)
103.25MHz: Satthani WItthayu Ratthasapha (Parliament Radio)
<500kHz, OK>
102.75MHz: Khao Kho Hong, Hat Yai (50W)
103.0MHz: Khluen Muanchon Khon Thepha {คลื่นมวลชนคนเทพา}
<250kHz, OK>
Next, I will show the coverage report of Khao Kho Hong at 50W power with 3 bay array dipole antenna in 3 different tower locations.
1. Khao Kho Hong (lower peak)
2. Khao Kho Hong (Upper Peak)
3. Khao Kho Hong (Hat Yai Municipal Park side)
According to the coverage, Khao Kho Hong upper peak and Hat Yai Municipal Park top peak have same coverage, but Khao Kho Hong lower peak (MCOT tower) has lesser coverage population. For border area transmission, lower peak Khao Kho Hong has coverage in Padang Besar, Perlis which is closer to Perlis FM 102.9MHz.
Besides that, the transmission of FM 102.75MHz from Khao Kho Hong will not interfere RTM Nasional FM 102.7MHz in Sintok and Bukit Kayu Hitam because it transmits at low power as much 50W. In Bukit Kayu Hitam, Nasional FM is still receivable and clear on 100.5MHz from Gunung Jerai.
Although FM 102.75MHz Khao Kho Hong has just only 50kHz frequency separation from RTM Nasional FM 102.7MHz UUM Sintok, but there is no interference impact within broadcast area, however Nasional FM 102.7MHz and Khao Kho Hong FM 102.75MHz have minor interference in Sadao, Thailand.
For my recommendation, as FM 102.75MHz covers Hat Yai only, so I suggest that FM 102.75MHz to be used at Hat Yai municipal park of Khao Kho Hong hill, rather than Upper peak (Radio Thailand tower) and lower peak (MCOT tower).
==Complete tentative RF proposal of FM 102.75MHz for Hat Yai transmission (for non-professional use only)==
- Frequency: FM 102.75MHz
- Power: 50W
- Transmission site: Khao Kho Hong (Hat Yai municipal park side), Hat Yai city, Songkhla province, Thailand
- Sample transmitter model: Elettronika MIZAR2 50
- Sample antenna model: SIRA FM-04 3 bay array dipole antenna
- Antenna polarization: Vertical
- Number of bay: 3
- Sample antenna height: 40m
- Height above sea level: 338m
- Antenna gain: 6.0dBd
- ERP: 200W
- Target location: Hat Yai, Thailand
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