Long wire antenna and Balun

Further in my learning curve about shortwave radio I was reading a scanning book, and it had a section for shortwave receiving with a long wire antenna. I am not sure if the reference was about scanners or HF receivers in general but it states that having a long wire straight into the radio will overload it with noise. I knew that, so some time ago I built an antenna tuning unit. The book also said that the wire coming into the loft will pick up more noise. So from the gutter as the wire goes into the loft I joined the long wire to some RG213 (centre wire only) which goes across the loft and down into the shack to the tuning unit and then to the radio. Then it stated that noise would be further reduced if there was a Watson Long Wire Balun fitted between the longwire and the coax. Apparently they did an experiment with the Balun without the tuner and tuned to 7 MHz, there was just a band of noise. With the tuner switched in with the balun the result was amazing with most of the noise gone. So really my question to the members is would a Watson long Wire Balun or any other balun help in getting rid of some noise in my shortwave receiver. Thank you Mike.