ALP 620, Directional antenna. ALP620 is a directional antenna type "shark fin" (LPDA) with good directivity (+7dBi) over a wide frequency range (450-862 Mhz band) ALP620 is made of 3 mm fiberglass in skeleton construction for minimum wind impact and is ideal for portable use. Bracket with 3/8" tripod thread, connection via protected BNC connector.