On 10/15/2013 8:28 AM, Mike Bryce wrote:
there are two wires, one of each side, that are 131 feet long. they meet in the
middle at the support and continue down 175 ish feet into the shack to a 1:1
current balun.
The feedpoint impedance of this antenna is close to 50 ohms on 160M.
Feeding it with high impedance open wire line is an unnatural act! It's
no surprise that you can't match it.
Replace that open wire line with 50 ohm coax and it will load nicely. As
to your "balun" -- those things often called a "current balun" are
really a common mode choke, and their most important function is to keep
noise picked up on the feedline from coupling to the antenna. To do
that, they must be AT THE ANTENNA, not at the shack.
When you're buying coax, don't buy junk from a CB vendor at a hamfest.
The Wireman sells the good stuff. Same with connectors -- if it doesn't
say Amphenol on it, it's junk. The Wireman also sells several nice
center insulators.
As to the "balun" -- see my RFI tutorial for detailed recommendations.
My material has been in the ARRL Handbook for several years.
http://k9yc.com/RFI-Ham.pdf
73, Jim K9YC
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|