Ham radio applications demand antenna design with an aim of achieving maximum gain, which is affected by
several factors. Impedance matching is one such factor which plays a vital role in such condition, as of improper
impedance matching causes the formation of standing waves resulting in the reduction of gain. Generally wire antennas
have an input impedance of 68Ω, which are detuned to 50Ω to have proper impedance matching with a co-axial cable; as a
result it leads to decrease in gain. Slim Jim is a special wire antenna which has impedance selectivity of 50Ω, 100Ω, 200Ω
and 400Ω. Due to the addition of a parallel element, the Slim Jim antenna has a considerable horizontal gain over the Jpole
antenna. This paper provides a comparative analysis of four wire antennas mainly used by HAMs with the appropriate
calculations using velocity factor and the results are discussed in detail.