How to Use a 900 MHz Yagi Antenna

900-930 MHz PCB yagi antenna
900-930 MHz PCB yagi antenna | Source

Introduction

Most 900 MHz antennas can be designed as dual use antennas, so that they work on the 1250 to 1300 MHz range as well. These 900 MHz / 1300 MHz antennas have a wide variety of uses.

1200 MHz or 1.2 GHz is part of the UHF ham band. 1.2 GHz is also called the 23 centimeter band. These UHF frequencies have their own assigned uses.

How can these antennas be used?

GSM

GSM stands for Global System for Mobile Communications, originally Groupe Spécial Mobile, which is French for Global System for Mobile Communications.

GSM is standard for more than 219 countries and territories, and a standard for 2G cellular networks. GSM networks operate in the 900 MHz band, for which this antenna is designed, or in the 1800 MHz band. In the United States, the 900 MHz frequency had already been allocated, so most Americans with GSM use the 850 MHz range.

GPS and GNSS

GPS (Global Positioning System) carriers in the L-band use 1176.45 MHz, 1227.60 MHz, 1381.05 MHz and 1575.42 MHz. GNSS or the Galileo navigation system, a parallel system to GPS, uses frequencies 1164 to 1214 MHz, 1260 to 1300 MHz and 1559 to 1591 MHz. Therefore, a 900-930 and 1250-1300 MHz antenna can be used for the GNSS/Galileo navigation systems that use the lower L band but not GPS applications.

Galileo is the European, civilian GPS equivalent. 1246 MHz is the central frequency of the GLONASS satellites, the Russian equivalent of GPS and Galileo.

Satellite Antennas

For satellite systems, the L-band refers to the 1-2 Gigahertz range. This frequency band is commonly used because it has a wide band width, so the antenna doesn’t have to be nearly as accurately pointed as antennas used for higher frequency bands. This 900-930 and 1250-1300 MHz covers the lower range of the L-band.

The 1.3-1.7GHz range is allocated to Inmarsat. The rest of the L-band is used for communications with GSM mobile phones, military satellites and low Earth orbit satellites. These antennas are sometimes used for satellite TV when the Ku and is down-converted to L-band. Since L-band has a limited bandwidth, C-band is more often used for these applications.

Wireless Communications

Antennas in the 900 to 930 MHz are regularly used in wi-fi and Wi-Max wireless networks.

ATV

ATV stands for Amateur Television. ATV is the broadcast of audio and video over the ham bands allocated for amateur use by the FCC. ATV is for non-commercial usage only. This means ATV can be used for non-commercial experimentation, public service broadcasts, community information services and pleasure. ATV is also called HAM TV or Fast Scan TV. ATV broadcasts are not de-codable by the standard television, not even before the hi-def TV conversion.

This antenna can be used for ATV frequencies of 1.25 MHz and below.

Many 900 MHz antennas are also used for ham radio communications aside from ATV.

Beacons

Marker beacons in the Instrument Landing System (ILS) use the 1300 MHz frequency range. This antenna is not recommended for that purpose.

Technical Notes

You can "pull" the tuned frequency of this antenna lower by dielectric loading, or you can raise it by trimming the element length(s).

The letters are small and have no effect on the performance of the antenna. Gain peaks near 7 dBi and is between 5 and 6 dBi at the edges of the 902-928 MHz band.

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