[SMCARA] More antenna fun from W4OKW
Clarke, Tom AIR4.0P NATOPS
frederic.clarke at navy.mil
Thu Jun 16 15:42:46 EDT 2011
This is a shortened folded dipole antenna for a
single band. Shortening the dipole raises the
input impedance and the vertical section is a
9:1 transformer, magically making it 50 ohms
at the balun. Somewhat narrow, but covers most
of the 40M and up freqs.
73 Tom
390/fMHz
___________________________________________
|__________________ _____________________|
| |
| |
| | 190/fMHz
| |
| |
| |
____
| B | 1:1 Current Balun
----
| 50 Ohm Coax feed (any length)
|
Band Top Section Vert Section Remarks
3.3 118 Feet 51 Feet MARS Freq
3.7 105 Feet 46 Feet 75 Meters
4.1 98 Feet 42 Feet MARS Freq
5.4 72 Feet 35 Feet 60 Meters
7.2 55 Feet 24 Feet 40 Meters
10.1 39 Feet 19 Feet 30 Meters
14.2 27 Feet 12 Feet 20 Meters
18.15 22 Feet 9 1/2 Feet 17 Meters
21.3 18 Feet 8 Feet 15 Meters
24 16 Feet 7 Feet 12 Meters
28.4 14 Feet 6 Feet 10 Meters
50.15 8 Feet 4 Feet 6 Meters
146 2 3/4 Feet 1 1/4 Foot 2 Meters
Formula = 390/fMHz 190/fMHz 450 Ohm Window line
415/fMHz 188/fMHz 300 Ohm Twinlead
No tuner reqd unless trying to force to another Band.
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