Currently the World Maritime
Organization (IMO) has identified 16 marine areas for broadcasting NAVTEX messages.
Iran is located in the IX area. This area includes the Persian Gulf, the Sea of
Oman and a part of the Indian Ocean. The PMO is in charge of maritime affairs
in the country. In line with performing its government duties, it managed to receive
the privilege of establishing two NAVTEX transmitter stations in Shahid Rajai
and Bushehr in southern Iran. Nevertheless, broadcasting regular messages is
also an important point. This requirement is in accordance with Clause 4 of the
SOLAS Convention: GMDSS. This monitoring in the IX area is carried out by Pakistan.
Obviously, any disruption to regular broadcast of messages cause prejudice to
the marine dignity of the country and has irreparable consequences in the international
community which cannot be justified by excuses such inter-organizational differences.
Many points should be
noted in this section. In short, the most important ones are provided:
1. The frequency range is 480-520 kHz which is considered
the low frequency band and has huge impact on human body based on Faraday and
Gauss rules. These effects are much more destructive than the frequency level
of the VHF, UHF, HF antennas and mobile band, given the inverse relationship between
frequency and wavelength.
2. The modulation of waves is of amplitude modulation
(AM) type. Given amplitude strengthening in this type of modulation, it will have
huge amplitude impacts when transmitting.
3. The allowable distance of the device is 100 meters
according to its power (1000 W), related modulation and documentation. According
to the UMNI DIRECTIONAL propagation of the antenna, a sphere with a radius of
100 meters is dangerous.
4. The antenna length is 90 meters. It uses the LONG
WIRE system to strengthen the signal. This increases the radius of hazard area
5. Flat areas are the best environment for propagation
6. Among similar transmitters with minor differences,
one can point to the transmitter of Radio Bushehr in the economic special zone
(which has a free distance several times this value) and the transmitter of Civil
7. Based on the international conventions, the development
of LRIT, VTS, HF and VHF systems is being pursued as relay stations given this