VHF/UHF are more critical than shortwave antennas. Their more size required more attention to design details to increase signal capture. The more gain an antenna has, the more directional it is, since gain comes from "shaping" the response pattern of the antenna to incoming signals.
The Grove Scanner Beam ANT18 has been through several minor iterations over the decades, and is now revered as "the" scanner antenna for serious monitoring. Although it's assembled with conventional TV-antenna, rolled-aluminum elements, this cost saving doesn't compromise its high performance which matches that of professional beams costing many hundreds of dollars. Use it for continuous-spectrum monitoring from 30-900 MHz at least. In the clear, its range approaches 100 miles radius.
Need higher gain? Planning to transmit? The rugged design of the Create log-periodic beam invites power to at least 100 watts, and the durable elements withstand high wind load. This is a professional antenna with a typical gain in the 10-12 dB range and a choice of 50-1300 MHz (CLP-5130 -1N) ANT16 or 100-1300 MHz (CLP-5130-2N) ANT17.
A popular favorite with scanner monitors and two-way users (up to 100 watts transmit) is the Nil-Jon ANT10MBS multiband base antenna. Designed for transmitting in the 140-174, 216-225 and 406-512 MHz bands, it also provides reception from 25-1300 MHz.
The Scantenna ANT07 has set itself apart from the others with its excellent, omnidirectional performance. If maximum range, all-around, and no rotating beam are your requirements, you won't do better than this 25-1300 MHz scanner antenna.
For casual scanner monitoring over metropolitan areas, the Grove Omni ANT05 can't be beat for price vs. performance. A 50 mile range isn't unusual on several scanner bands between 30 and 960 MHz.
Discones have their place. While they don't offer the gain of other designs, they do offer uniform response in all directions, and on all frequencies continuously through their design spectrum--and, because of their constant impedance over their design bandwidth, they can transmit as well as receive throughout the design frequency range. Choose the Winradio AX-71C ANT01 for reception from 30 MHz right up through 3 GHz, the AOR DA3000 ANT11 for 30-2000 MHz, or the Diamond D130J ANT09 for more conventional 30-1300 MHz coverage.
Transmitting as well as receiving?
Looking for extremely wide frequency coverage 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 it does it well.