Doing some googling, I cam across the Titan Missile Museum in America, where they have a HF discone.
Those who have a discone that tells you it works from 0.5 mhz or some other stupidly low frequency, may like to take a look at how big this thing is & it's not designed to work as low as 0.5mhz that 600 meters. But instead 6 Mhz which is only 50 meters to 30mhz or 10 meters.
I know the Titan Discone is designed for Transmit. But scale is important, even on RX. A discone is smaller than a handheld antenna is at 10 meters & how many here would recommend a slightly longer & better handy antenna for VHF & UHF listening?
The Titan antenna is apparently 80 feet tall.