No power relay device -Wikipedia

Non -powered relay device installed on the hillside of the mountain

No power relay device (Mukyu Denchui Sochi) is a relay device that does not have an amplifier in wireless communication. Passive repeater （ passive repeater )

The mainstream is that the radio wave is reflected by the metal plate, but there is also a form that combines two parabola antennas to the back match, transmitting and emitting radio waves received in one antenna to the other antenna with a waving tube. In each case, the direction of radio waves is used, and it is mainly used for frequency of 3GHz to 30GHz band. Since no power is required, it can be constructed at a lower cost compared to general wireless relay facilities.

Usually, when wireless communication using radio waves in the SHF band, there are no obstacles between radio stations () Inner propagation （ English edition ） ) Is required. Therefore, in places with many obstacles, such as mountainous areas, a relay station that once receives radio waves at another wireless station and resends it. Normally, power supply is required because the receiver and transmitter are relayed, but under specific conditions, a mirror -like one may be relayed by providing a mirror -like one that reflects radio waves. The condition is that the distance between the reflector and one relay station is relatively short, and the incident angle of the reflector is higher than a certain level.

Install a board made of material suitable for reflection of radio waves (like a parabolic antenna reflector is a plane -shaped plan), but there is no antenna function in the device itself (just reflects the radio waves). Because it is not, it is called a non -powered relay device. In order to transmit efficiently, the reflective surface requires smoothness. Snowfall and icing are great enemies, and in the snowfall and cold areas, a string -shaped one is installed on the front of the reflector to prevent it by rubbing the reflective surface in order to prevent it.

Actively broadcast Micro wave relay device （ English edition ） Compared to (relay station), the non -payable relay device is much simpler, has less maintenance, and does not require a power supply. The relay station needs to change the frequency of transmission and receiving to prevent feedback, but there is no need for a non -supply relay device. The drawback is that the reflected signal is weakened because it does not amplify.

How to be used [ edit ]

It is a facility that is often found in disaster prevention radio, which is often visited to communicate with mountainous villages and dams, and often found in the hydropower plant installed in valley, and can see plate -shaped objects in the mountains and mountains. be. By combining two reflectors, the radio waves are often relayed to almost the same direction as the original route.

Although there are few examples, this device is also used in the broadcasting field. TV Yamaguchi and FM Yamaguchi have a ridgeline between the head office (studio, etc.) of the head office in Yamaguchi City and Oirayama (Hofu City), a transmitting station, so their own bureau is on the hillside of Yamaguchi City. A non -supply relay device has been provided. In addition, there is a reflector of TV stations concentrated near the area near Tsuchiyu Onsenmachi, Fukushima City, Fukushima Prefecture, and TV You Fukushima Takayama reflect board is located in Yokomora, Inawashiro -cho, Inawashiro -cho, Inawashiro -cho, Inawashiro -cho, Ashito Onsencho. The NHK Fukushima Broadcasting Station field reflector has a Fukushima TV field reflector in Wakamiya, Inawashiro -cho (see Noji Onsen#Wireless relay facility).

Related item [ edit ]