Topband: UNUN for Inverted L
ku8e at bellsouth.net
Fri Feb 10 13:09:27 EST 2006
I just bought a 1.78 : 1 UNUN for my inverted L.. It is a W2FMI 1.78:1 HDU50 . Says it is for
inverted L's, short verticals.
My antenna is close to 130 feet long - 50 ft vertical and the rest horizontal. I have 4 elevated
130 ft full size radials and a few also cut for 80 since I have a jumper to use it on that band as well.
When feed the antenna directly I have a SWR below 2:1 for about 50 kz. When I add the UNUN in line the SWR goes above 3:1 and can't seem to get it below that even though I have adjusted the wire length of the antenna. I can't seem to find a SWR dip anywhere with the MFJ antenna analyzer. Did I buy the wrong UNUN ?? or maybe I have it hooked up wrong. I have it installed
at the feedpoint of the coax and wire. I have tried both the 50-12.5 and 50-28 ohm positions.
They also sell an UNUN that is for 50ohms -22 ohms and 50 ohms- 25 ohms (2.1:1 HDU50) but the description says it for matching a junction of two parallel 50 ohm coax cables.
Jeff , KU8E
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