LWC Sysytem Now . . . The complete answer to your interference problem . . Either the LWC4 or the CT400 will work quite well as a coupling transformer to allow the use of a low impedance co-axial feeder with a single wire antenna. With many modern receivers this is no problem.
Most tuners work best when coupled to a relatively HIGH impedance wire.
The natural impedance of a wire antenna varies considerably with its length, height and the actual frequency in use. At all other frequencies there is bound to be some loss of signal due to this inevitable compromise. Generally, because this 'loss' is usually compensated for by the AGC action of the receiver and, because a lot of noise has been screened away, the signal is cleaner and easier to copy.