If your are just going to receive.. simply stick a random length of wire into the center pin of the antenna connector lol I'm serious...longer is better.
for transmitting you need a "real" antenna.
An end fed 1/2 wave maybe what you need. 40 meter version is about 63 feet long. get you 40 to 10 meters.
There are numerous folks sell these or you can make one yourself. a quick internet search will spit out numerous plans and instructions.