Project: 137 MHz QFH Antenna for Weather FAX

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The weather FAX NOAA satellites transmit around 137 MHz and orbit the earth frequently as low earth orbit satellites (LEO) in ~800 km height. So the elevation is also changing with the actual position, which can be rising from the horizon up to overhead and back.

A standard vertial or horizontal antenna work, but not for all elevation positions. Here a Turnstyle or a quadrifilar helical (QFH) antenna is better suited. I decided for last one.

David, F4BPP, has an excellent construction example on his homepage. It was quite easy to build an own one:

The QFH antenna is mounted on the house roof beside the other antennas (space becomes rare, hi). The upper arrow shows the antenna and the lower one the weather protected 137 MHz SAW filter with pre-amplifier.

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