Walter, you have a 500ft loop?? Wow.. can you provide pictures at some
point? I'd love to see this in action. I'm using a 100ft longwire that
is
end-fed at this point by a matching balun. I use RG8 low-loss coax. I'm
tempted to try the more expensive Belden 9913 -- but it's about $100/50ft.


For anything below 30 mhz you will see no return for the money by going from
a good grade of rg-8 to the 9913 type. It would be difficult to see much
differance even if the rg-8x is used. Especially at 20 meters and below.
You would be beter off spending the money on a beter antenna than the long
wire.
Or making the antenna higher.