Avoid noise, boost performance: make a perfect coax feed line.
The perfect feedline
How to install your antenna properly
How to get the best from your coax



This 4:1 transmitting balun may be overkill for reception, but good step-by-step description making it easy to build.
4:1 balun for 160 to 10 meters



Amateurs are almost religious about balancing their antennas - in order to get the most power into, and out off, the antenna. But receiving antennas, do they really have to be balanced?
Well, yes and no. It all depends...
Read, and learn, more about this subject:
The purpose of a balun
"Matching less important for reception"
"Matching is important - it gives better reception"
"Not necessary to balance longwires"
"You must use a balun to balance your dipole..."
Balun or Antenna Tuner? It all depends...



Instead of making your own balun you may buy a comercial one, such as the Magnetic Longwire Balun.
Magnetic Longwire Balun

But... Tests by DXer Alan Johnson, John Doty and others reveals that the MLB is over-priced. There are several better, and cheaper, alternatives. Read, and judge for yourself:
MLB -- a con or not?
MLB -- not really a balun

John Doty: The ICE 180 is the least expensive transformer of this type on the market. Solidly built, it gives you good performance at a nice price.
ICE 180 -- best transformer buy

KC2CAU: After years of experimenting with wire antennas while living in a very noisy urban environment, I have concluded that the RF Systems MLB is indeed not a gimmic, and totally destroys the ICE 180 hands down!
MLB is not a gimmic