sigma 4 style homebrew
Hi Guys, my passion for cb has been recently rekindled, it's been many years but i did once own an original sigma 4, i had also owned a fake one amongst many other antenna.
I have a few questions if anyone can help.
I am building a copy with parts i have lying around but there are a few things i am not sure about, i am going to build a gamma match but i don't know the exact dimensions of the parts, does anybody know the length of the tube and rod? Must they both be aluminum? Even if the gamma match must be aluminum could the basket be made out of soldered copper tube?
I was going to make a version from wire and suspend it between two 40M pine trees but then found that i had a large glass fiber wind surfer mast and an extendable fishing pole that fits exactly in the end, i can achieve the length required and was planning on using aluminum or copper wire, to be hung on the outside (rather than inside) of the fiberglass tubes (to avoid some shielding).
So basically the questions are:
1? Gamma match dimensions, and is alu necessary? (also is there a good source for a teflon sleeve or equivalent)?
2? Can copper be used as a basket or must it be made from alu?
3? Can the main 27' 7" radiator be copper wire? or must this also be alu?
4? Does anybody know of any interesting mods. other than the obviouse waterproofing and filing the corners of the gamma match etc?
5? Since reading some more on this forum i am wondering if a thicker radiator above the basket would benefit rather than a thin wire?
So with the glass fiber poles i should be able to get the antennae to the top of the largest 50M pine tree just behind the shack although i am probably barking up the wrong tree since i live at 1200M almost at the bottom of a narrow valley on a fairly steep hillside surrounded by 3000-4000M peaks
I must admit that i've only managed to get as far as page 16 so far on this thread, i've been up all night reading and must get to bed soon, but a few thoughts, i was thinking of making the basket out of copper pipe since it would be easy to fix together, strong (but heavy) and a smooth finish, (better in wind). But is copper going to be better and is smooth a good thing?
I was going to use wire to make the cone but it seems that from what i have read here perhaps this design may benefit from thicker materials for the cone? And what about adding a second ring larger and lower down, i know that it's not exactly practical but perhaps it's worth a try, it could hang from the 30" ring and either be grounded from above or insulated from above and grounded from below (simply attached with wire or/and nylon rope from either above or below)?
What if it wasn't a cone but more of a cylinder? Average the size of the cone and make a cylindrical sheild, groundplane? Or whatever it is?
Just some mad ideas to play with, not much mathmatical theory going into that but i've got that ground plane magnetic pull feeling thing going on 
James
