Advice for newbie please

Hi after being accepted and getting my call sign I need some advice on antenna please, I’ve just  bought a crt crt ss 9900 , I will have this radio in my loft which is my man cave , what is the best antenna to use please in the loft? I  do have a skylight which in the warmer weather I can open and put up something through the skylight?
Much appreciated

If you can install outside any kind of antenna is way better.
One good option for outside is the silver rod 1/2 wave but is about 5.40m long.
If only option is inside the loft, one option is the Sirio Singal Keeper 1/4 ground plane (assuming will be away from any electric such wall cables, main board switches etc) & the Sirio Boomerang L-dipole but for inside personal i believe the Signal Keeper may be better option
An other option & maybe cheaper & sure more effective is to use wire to make horizontal V-dipole so the wire to follow the V shape of ceiling but with this way will be kind of directional

how high is your window above the ground? Or is there a chimney on which you can mount an antenna mast? Are there any trees around? As you might guess i also support the outside option. Inside i also would opt for the DIY inverted-V.

Aerial in same room as radio not a good idea