I need some advice in my quest to get the best possible performance out of my 135' doublet that is fed with 4" spaced (~600 ohm, supposedly) home brew ladder line. Background: It's up about 50' at the center. The ends are 65' + 75'. It's hung from pine trees and the 135' wire is strung over smaller trees below. The doublet and feed line wires don't come close to touching any trees at all. Feed line originally connected to the internal 4:1 unun in the Ten-Tec 238B Original problem: noise on 12 + 10 meters, like S-5/6 steady when the bands aren't open. I tried adding twist to the LL with no noticeable change. Solution: (partial?) I gave up on the tuner internal 4:1 unun and installed Radiowave B14CF Ferrite Core BiFilier Dual Core Guanella 4:1 current balun I had on the shelf, that dropped the noise floor substantially, to S-1 or less. It is still not as low as my nearby coax fed fan dipole on a 90 degree axis compare to the doublet. While S-1 noise floor is an improvement, I still want to get the most performance I can out of this antenna system. I've searched the all the massive amount of antenna books I have, the internet, this forum and I have determined there is much conflicting information out there. (understatement) My question: I want to get the best 1:1 balun to see if it will choke off even more of the noise floor. I wanted to build one or buy one if I have to. I haven't found any concise information on what to buy, what to build or how to build it. Palstar's offerings are ~$100, very little specs besides power handling capacity. DX Engineering's high powered offerings look pretty sweet, but again do not supply the actual lab tested specifications of how well they work. They cost $175-$195 (that's a high price if they don't work better than everything else) Anyone have any real world experience on what 1:1 balun I can build or buy that will handle legal limit and will shed the most common mode current for 10-80 meters?