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Tallysman’s AJ977XF antenna provides new approach to jamming mitigation

October 31, 2022  - By
Photo: Tallysman Wireless

Photo: Tallysman Wireless

Tallysman Wireless has added the housed AJ977XF triple-band antenna with anti-jam technology to its line of GNSS products.

According to Tallysman, the AJ977XF uses a novel stacked antenna phased array that creates a null of typically 20-dB attenuation in the antenna’s radiation pattern from the horizon to an elevation angle of approximately 15 degrees.

The null in the radiation pattern strongly mitigates in-band and out-of-band signals. For example, the AJ977XF will continue to function in the presence of a ground-level 600-watt jamming signal, 100 meters or greater from the antenna. In addition to the null in the radiation pattern, the antenna’s OP1dB (compression point) is 15 dBm, which strongly protects the antenna’s low-noise amplifier (LNA) from saturating.

The triple-band AJ977XF antenna supports GPS L1/L2/L5, GLONASS G1/G2/G3, Galileo E1/E5ab and BeiDou B1/B2ab), and, in the region of operation, satellite-based augmentation systems (SBAS): WAAS (North America), EGNOS (Europe), MSAS (Japan), or GAGAN (India).

The AJ977XF is housed in a through-hole mount, weatherproof (IP67) enclosure. L-bracket (PN 23-0040-0) or pipe (23-0065-0) mounts are available for permanent installations.

The radio frequency spectrum has become congested worldwide as many new LTE bands have been activated. Their signals or their harmonics can affect the proper operation of GNSS antennas and receivers.

In North America, the planned Ligado service, which will broadcast in the frequency range of 1526 to 1536 MHz, can negatively affect the reception of GNSS signals. Similarly, new LTE signals in Europe [band 32 (1452–1496 MHz)] and Japan [bands 11 and 21 (1476–1511 MHz)] also have been shown to affect GNSS signal reception. Tallyman’s new AJ977XF mitigates the effects of these new signals.

About the Author:


Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.

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