Don't know what a Cobra is.

But a 124-feet (38 metres) dipole, at a height of 40 feet (12 metres)
in conjunction with 60 feet (18 metres) of 450-ohm ladder line and an
L-match tuner has the following characteristics -

Freq MHZ Loss relative to ideal
1.9 8 dB
3.8 0.5 dB
7.1 0.9 dB
10.1 0.8 dB
14.1 0.6 dB
21.1 0.6 dB
29.0 0.6 dB

Loss includes, antenna, line, tuner and ground.

Data obtained using program DIPOLE3 from website below.
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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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