Topband: matching 5/16 inverted-L question

[sasas asasas]

Hi, i have an 5/16 inverted-L nad for matching with my 50ohm transmitter i am using just a series variable capacitor 0-500pf. I am using 1 meter coaxial 50ohm cable to connect the transmitter with the capacitor and the antenna is connected directly to the capacitor. The capacitor is in a box with silicon oil. The swr now is about 1.1 .
Because of, i am thinking to move the antennas feed point out of the transmitter's metal house (now the variable capacitor and the feed point are into the transmittr's metal house)
i have decide to use about 2 meters coaxial 50ohm cable to connect the capacitor (which will be stay into the house) and the antennas feed point (which will be out of the metal house).
I would like to ask you if this additional coaxial cable will produce any problem as regards the antenna's matching. I ask you that, because i know that, this additional cable will produce a paraller capacitance between antenna's feedpoint and the ground. The series variable capacitor can cancel this paraller capacitance? I will need something else to cancel this capacitance, like a variable coil?
I would not like to move the variable capacitor out of the metal house, to connect it directly to the antenna's feed point because of the rain. 
thank you very much.