CHOOSING A SHORTWAVE RECEIVING ANTENNA
Whichever antenna you choose, it's best put outside, reasonably high, and away from power lines and your dwelling to reduce electrical interference. Next best bet is an attic crawl space as close to the roof peak as possible. Always use coaxial cable from the antenna to the receiver; its shielding prevents the intrusion of electrical noise from its environment.
The choice of antenna isn't really all that critical for shortwave listening. Typically, a random, 20-60 feet of wire is entirely adequate for listening between 1-30 MHz, and the coax may be attached anywhere along its length. It is usually attached at or near the center of the wire since that's the place that a reasonable impedance is obtained most often over a wide frequency spectrum. Even so, larger antennas with better impedance matching may provide more signal, but they also provide more noise, so the net result of signal above atmospheric noise (hiss and static) is about the same.
If you are using a long antenna wire, chances are you will get signal overloading on your portable radio. Portable multiband radios have poorer dynamic range than the more professional desktop receivers, resulting in phantom signals appearing all over the spectrum. In such cases, try listening with your attenuator (DX/LOCAL) switch activated.The PAR "END FEDZ" ANT08 is a superb listener's antenna with superior construction materials. Since it's end-fed, the coax can be shorter, attached to the close end of the wire. Its 9:1 impedance-matching transformer brings higher signal levels to your receiver.
Want to "roll your own?" The WiNRADiO WR-LWA-0130 ADP35 adapter is a weatherproof matching transformer that allows you to attach a long wire of your choice, and still have reasonable impedance matching with your receiver.
Cramped for outside space? Don't want the neighbors to know you have an antenna? The H800 Skymatch ANT15 is an outstanding active antenna that employs a booster amplifier to make its short (3') length sound like a 100' dipole! It is powered by a wall transformer or, for total isolation from power lines, you may install two 9-volt batteries. Its high performance is the widest frequency range of all--10 kHz through 54 MHz.
Is an indoor or radio-room antenna a necessity? Do you have weak signal reception even with an outdoor antenna? Then try the MFJ 1020C ANT19 active antenna which is a handy accessory, allowing sharp signal-peaking from 300 kHz-40 MHz. It can also be used as a pre-selector/pre-amplifier for outdoor shortwave antennas.
Want to null out that indoor interference? Would you like to add VHF signal capture? The AOR LA390 ANT55 loop offers professional performance. It features an internal high-gain amplifier (18 dB), 10 kHz-500 MHz frequency range, excellent overall strong-signal handling (high IP3, +10dBm), all in a sturdy, tunable loop which can be rotated to reduce indoor electrical noise sources and maximize directional reception.
Looking for extremely wide frequency coverage all in one antenna? The low-profile AOR SA-7000 ANT39 vertical covers 30 kHz through 2000 MHz to match the new breed of wide-spectrum receivers and scanners.