| KX-137
VHF Satellite Antenna for polar orbiter satellites with built-in Preamplifier and High-Q-Filter. |
| The KX-137 provides best omni-directional reception results for polar orbiter satellites in the 137 MHz band. Thanks to the gold-colored anodized aluminum elements it does not only look good, it is weatherproof and durable. In situations when the KX-137 may be too big or striking, e.g. on board ship, our MX-137 is an interesting alternative of nearly the same reception performance. |
Details of Construction and Operation
| Two horizontally mounted crossed dipoles are coupled through a phase shifting network so that true circular right hand polarized reception is achieved. For signals arriving parallel to the surface this arrangement acts as an omnidirectional linearly polarized antenna. With increasing elevation angle we get an increasing vertical radiation component and the polarization changes from linear over elliptic into circular. Thus the up-looking KX-137 is the ideal counterpart to the downlooking satellite antenna and always gets the maximum possible radiation energy. A very low-noise preamplifier with high-Q-filter is integrated inside the antenna head. In that way, the KX-137 avoids the performance-degrading cable- and matching losses, always present in other configurations and effectively suppresses interference from strong neighborhood-stations, like aviation or ham-radio. A passive reflector amplifies reception from the satellites above and reduces fading caused by surface reflections. To enable the KX-137 to unfold its full performance, it should be mounted so that there is always a line of sigth to the satellites (on the roof, not under it). Then noise-free images in a range of about 5000 km can be expected. |
| Not only the principle of operation is ideal, also the quality of material and manufacture is best: Stainless-steel screw connections of the elements allow quick and easy antenna installation. Aluminum parts are longlife anodized. All sensitive electronic parts and components are shielded in the water- and UV-resistant antenna head box. The mast mount is made of galvanized steel, screws and nuts are stainless steel. Availability of replacable parts is guaranteed for many years ahead. |
Technical Data
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| AA-137
Selective VHF-Preamplifier (recommend for passive antennas, already integrated in our KX-137 and MX-137!) |
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| The AA-137 preamplifier not just compensates for cable losses, it improves the noise figure, sensitivity and selectivity, e.g. overall system reception performance. The five hi-Q-Filters are carefully adjusted on our network analyzer workplace. They create an excellent selectivity against the nearby aviation and ham-radio frequency bands. DC power is automatically fed from the receiver through the coaxial feed line.. |
Technical Data
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