Kreco Discone

Low SWR Over 8 to 1 Range

Disk and Cone are Fabricated of 12
Radials

Must specify UHF or Type N Female connector.

Frequency Range
D-100A 1" 12 lbs. 100 to 800 MHz
D-150A 1"  4 lbs. 150 to 1200 MHz
D-300A 1"  4 lbs. 300 to 2400 MHz 

Source:

http://www.krecoantennas.com/broadband.htm

Diamond Discone Antenna

The D3000N Super Discone Antenna is an ultra-wideband antenna covering amateur radio, commercial 2-way, cellular, air traffic control and various utility frequency bands. Rust-free stainless steel is employed in major component parts making the antenna rust resistant and durable.

Specifications:
Bands: 25-3000 MHz
Gain dBi: 2 (nominal)
Max Power Rating:
144 MHz up: 200 watts
6m: 20 watts
FM, 50 watts PEP
Height:    67"
Connector: Type-N
Element Phasing: Wideband Discone

Remarks: Adjustable 50-54 MHz 

Source:

https://www.diamondantenna.net/d3000n.html

Comet Discone Antennas

Comet Discone DS-150S
Extremely wide-band Scanner/Receive antenna.
Includes 65 feet of RG-58A/U coax with PL-259 connectors installed

RX: 25-1300MHz
TX:  6M/2M/440/900/1200MHz
Length: 4′ 8″
Max Power: 100 watts
Weight: 3lbs 3oz (without coax)
Connector: SO-239 

Source:

https://cometantenna.com/amateur-radio/base-antennas/discone/

 

Antenna Discone

The discone antenna has a useful frequency range of at least 10 to 1. When employed as a transmitting antenna, it is often less efficient than an antenna designed for a more limited frequency range. SWR (standing wave ratio) is typically 1.5:1 or less over several octaves of frequency.
A discone antenna consists of three main parts: the disc, the cone, and the insulator.

The disc:

The disc should have an overall diameter of 0.7 times a quarter wavelength of the antenna's lowest frequency. The antenna's feed point is at the center of the disc. It is usually fed with 50-ohm coaxial cable, with the center conductor connected to the disc, and the outer conductor to the cone.

The cone:

The length of the cone should be a quarter wavelength of the antenna's lowest operating frequency. The cone angle is generally from 25 to 40 degrees.

The insulator:

The disc and cone must be separated by an insulator, the dimensions of which determine some of the antenna's properties, especially on near its high frequency limit.

https://en.wikipedia.org/wiki/Discone_antenna

On the market there are several manufacturers of antennas, some of the best known to radio amateurs, listeners, SWL, but there are also some less known models that are very efficient:

Discone Antennas:

Comet
Diamond
Kreco