The J-Pole antenna is an excellent choice for a low cost scanner antenna that is capable of picking up signals from a wide range of frequencies. Many scanner aficionados prefer the discone antenna, but the J-Pole has some distinct advantages over discones for scanner monitoring.
The advantage of a discone antenna is that it is very broad banded, it will pick up signals from a very wide range of frequencies. It also has a rounded RF pattern, so it will pick up signals high in the sky, such as airplanes, equally well as signals from the horizon. But the broad banded nature and uniform radiation pattern of the discone means that the antenna doesn’t have any gain.
The J-Pole is a half wave antenna by design, so it has about 3 db of gain when compared to the discone. Its pattern is more donut shaped, so it will favor signals at the horizon, than in the sky. That makes it an excellent antenna for land based stations. Although it doesn’t have the broadbanded nature of the discone, it will receive from a wide range of frequencies, and the heavy copper construction makes for an extremely quiet antenna. The antenna has more surface area to receive signals, giving it a lower noise floor than comparable antennas.
An excellent choice for a scanner antenna is my VHF Marine and Scanner antenna. This one is tuned for the VHF 155-160 MHz range. If you primarily listen to UHF signals, then you will be interested in the GMRS antenna which is tuned for 462-467 Mhz.