900MHz GSM Booster Omni Antenna | 900-930 MHz 3dBi

A short 3 dBi omni for 900-930 MHz, built on a 300 mm fibreglass radome 20 mm in diameter and weighing 0.2 kg. The horizontal pattern is a full 360 degrees and the vertical beam is 30 degrees, VSWR is at or below 1.5, and the single port is available as N-Type female or N-Type male. It is intended to mount directly on a booster or repeater enclosure rather than on a mast.

A booster antenna, not a coverage antenna

A 3 dBi omni is the lowest gain in the 900 MHz range and that is intentional. It is designed to sit on a signal booster or a small repeater, where the objective is to couple the radio to the space immediately around it rather than to reach a distant subscriber. Mounted directly on a booster enclosure, the antenna is part of the equipment rather than part of the site.

Where the requirement is coverage of a building or a yard, a 5 or 8 dBi antenna is the correct part. The 3 dBi unit is used when the radio is already close to the coverage area and additional gain would only narrow the pattern without adding useful range.

The band is 900-930 MHz, not all of GSM 900

The specification covers 900-930 MHz, which is narrower than the full GSM 900 allocation. In most regions the GSM 900 uplink sits around 890-915 MHz and the downlink around 935-960 MHz, so this antenna covers part of the uplink but not the downlink. Before specifying it, confirm the actual channel plan of the booster or repeater it will serve.

If the installation needs the full 824-960 MHz range, the 824-960 MHz wideband omni covers the wider band. Using this antenna outside 900-930 MHz will produce a poor match and unpredictable coverage.

Coverage from a 3 dBi pattern

At 3 dBi the vertical beam is 30 degrees, which is wide enough to cover a room or a small outdoor area without a dead zone directly under the antenna. Mounted at 3 m, the beam reaches the floor at about 5.6 m from the base and extends to roughly 100 m outdoors with a 2 W booster.

That geometry is the reason this antenna is often used indoors as the service antenna of a repeater: at ceiling height it fills a floor area evenly, and the 360 degree pattern means the coverage does not depend on which way the unit is aimed.

0.2 kg and direct mounting

At 0.2 kg and 300 mm, the antenna can be mounted directly on a booster enclosure with an N-Type male connector, which removes the feeder and its loss entirely. For a low power booster, removing 2 m of RG58 and two connectors is worth more than 2 dB of antenna gain.

Where a feeder is required, keep it short and use a low loss cable. At 900 MHz the loss of thin coax is about 0.6 dB per metre, so a 5 m run can cost 3 dB, which is more than the difference between this antenna and the 5 dBi version.

Ordering

Connector gender, radome colour and packing quantity are confirmed at order. Samples in 3-5 days, production in 15-25 days.

For a wider band omni at the same frequency, the 5 dBi 900 MHz GSM omni antenna covers 824-960 MHz in a 600 mm radome. For a directional donor antenna rather than an omni, the 12 dBi GSM Yagi antenna provides 55 degrees of directivity at 0.6 kg.

Send the booster model, the channel plan and whether the antenna is for the donor or the service side. The channel plan is the first thing to check, because this antenna does not cover the full GSM 900 downlink.