Alison Microwave Ltd is a designer and manufacturer of robust high performance GPS and DPS antennae and ancillaries for long term installations in harsh environments where maintenance free reliability is required
Suppression of near-band interference • Corrosion resistant • Bespoke options
· All AML antennae incorporate hard anodised milled aluminium bases with 4mm thick GRP radomes, giving strength and superb corrosion resistance. Titanium bases with glass radomes are used for the deep sea submersible antennae, which are produced in partnership with Nautilus Marine Service GmbH.
· Standard antennae can be rendered inoperable due to interference close to the operating frequencies as a result of spectrum crowding. AML manufactures a range of antennae with integral low-loss comb and interdigital filters designed to suppress near band interference and maintain continuity of reception during high precision measurements. Bespoke filters can also be manufactured to a customer’s requirements.
· Each antenna has a low noise amplifier with an overall noise figure including filters of less than 3dB and a factory preset gain in the range 20 to 45 dB. Supply voltage is 3.3V to 20Vdc at typically 42mA. Other gains are available on request.
· The antennae elements are either dielectric patches, crossed dipoles or quadrafilar helical radiators depending on the application. The elements have right hand circularly polarised (RHCP) radiation patterns (LHCP optional) that are uniform in azimuth and offer good reception in elevation.
· All antennae are EMC approved, compatible with a wide range of GPS/DGPS receivers and tested against an appropriate reference prior to dispatch.
· JP614460-01 certification for selected antennae (AD420, AD491, AD591) representative of mechanical, filter and amplifier configurations used across the full product range.
· AML antennae are designed and manufactured in house using state-of-the-art facilities. Consequently, custom requirements ranging from modification of existing products to the development of new antennae can be met efficiently.
· These units are used to feed an antenna’s output to the GPS and/or DGPS inputs of one or more receivers. Active (with typically unitary gain) and passive splitters are available, with a DC pass through or block for each of the ports as required. Isolation between outputs is better than 20dB.
· A long cable run between an antenna and receiver leads to significant signal attenuation and as a consequence in line amplification may be necessary. AML manufactures in-line-amplifiers typically with preset gains of 8, 12 and 18 dB with either a DC supply pass through (AD200/8) or a DC block (AD200/9) as required. It is recommended that the amplifier is placed near the beginning of the cable run.