Using one doesn't help, because when you "peak" the tuner to increase the wanted signal, you also "peak" the general noise level.
http://www.hard-core-dx.com/nordicdx/antenna/special/notuner.html
http://www.rfcafe.com/references/electrical/microstrip_eq.htm
The construction of a long-wire antenna is simple. By adding an easy to build Pi coupler you will get even more signals from your wires.
http://www.hard-core-dx.com/nordicdx/antenna/lab/coupler.html
Modern shortwave receivers, especially portables, most often are intolerant of overly strong signals. Therefore, the best, and least costly, antenna is the least antenna that can receive what you want to receive.
http://www.hard-core-dx.com/nordicdx/antenna/special/minimal.html
http://electronics.howstuffworks.com/question490.htm
tips for installing FM and TV antennas to roof.
http://www.siber-sonic.com/FM_reception/rooftop.html
Ruthroff 1:4 coax transformer, both the balun and unun forms.
http://www.bytemark.com/products/tlttheory.htm
http://www.qsl.net/n9zia/wireless/sealing_andrews_connectors.html