Topband: 160-80M Inverted-L antenna ?

[Gary Marks]

    I will be making and erecting an Inverted-L antenna for 160m & 80M very soon. This is my first wire antenna and the first on these two bands. I've read several of the ARRL books and while learning a lot about antennas....I'm also confused about several aspects of there construction.

    I will have to live with the supports that I have available (tower and trees) so I am somewhat limited on horizontal distance. My plan is to run my antenna wire about 5 feet (or a little more if needed) away from my tower (70 foot crank-up) vertically for about 66 ft. then through a ceramic insulator and the remainder of the horizontal portion to a tree that has a pulley up about 55 ft. Just guessing at this point but the total length of the wire will be 138 feet plus or minus. Since the end is near the pulley; I can lower the end to trim it to a specific length. I just purchased an antenna analyzer which I've used to check some of my other antennas which has answered some questions but created just as many more. This is a learn as I go process.

    Since this is a dual band antenna; I understand that I will need some type of matching network at the base of the antenna and a way to switch from 160M to 80M and back again from inside my shack. I have know idea what I will need other then some variable capacitors and a coil all in a weather-proof box. I plan to use 50 ohm coax feedline.
Could someone on the list please steer me in the right direction as to the correct components for my matching network and a company that sells these components. I've read that some use air variable capacitors and doing an internet search for these has shown the price to be too high for me. I do not have the time to search the hamfests as I'm trying to finish this antenna before Winter. I understand that the solar minimum is great for these two bands and I've never operated on 160M before and I'm looking forward to working some DX.
Any and all information will be greatly appreciated.  

THANKS

Gary
WD8ICX