self made cross dipole for 137 mhz
the idea is from Daniel Moeller, DL3RTL
this copy of picture and information has permission from Daniel Moeller, DL3RTL
seen at http://www.fading.de/wettersatelliten.php
this is the circuit for the right-hand circular polarization antenna
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A till D, 510 mm E coax cable 50 ohm, 361 mm F coax cable 75 ohm, 361 mm 2 times, parallel G 50 ohm antenna cable |
and this is the temporarily mounted antenna at my solar collectors
as you see, this is only made until the next rain, when corrosion will separate connections and soldering points.
this is the swr after some tuning steps. i reduced the total length over 2 dipole elements to 102 cm. the elements itself are abt 506 mm. marker 1 is the center of 137,5 mhz. the swr minimum is still at 118,4 mhz however. to enlarge, click in the picture. marker 2 is 137 mhz and marker 3 is 138 mhz.
picture made with fa-nwt01
8/2009