Topband: UNUN for Inverted L

Tom Williams N2CU n2cu at
Fri Feb 10 20:34:21 EST 2006


My inverted L is 46' vertical and about 95' horizontal with 20 on-ground
radials between 70' and 180' in length. My MFJ won't give me a correct
reading of impedance because of RF from a nearby (<10mi.) 50 kW AM station
so I use the SWR meter on my rig. The lowest SWR I saw was around 1.4:1 when
fed directly with 50 Ohm coax. I bought the AB 240-250 kit from Amidon and
wound a 2.25:1 UNUN. The SWR is now 1:1. I plan on putting down about 40
more radials so my feedpoint impedance will undoubtedly change but I felt
the 2.25:1 would give the best match.

Tom N2CU <><

More information about the Topband mailing list