So far, everyone is close.
Radio doesn't matter. Length of cable doesn't matter. Whether the cable is coiled, rolled or in a mess, it doesn't matter. Length of antenna doesn't matter.
What does matter? A good ground for the radio. A good ground for the antenna. A good SWR.
SWR is Standing Wave Ratio. It the ratio of power that being transmitted versus the amount that is being reflected back towards the radio from a bad impedance match.
Theoretically, a ratio of 1:1 is ideal, but is unachievable. A SWR of 3:1 or less is what you are looking for. This is what we tried to achieve on the boat when transmitting via HF at 1000 Watts.
An external SWR meter is needed. The ones in the radio are ok, but not very reliable.