You can buy an almost all plastic briefcase with a plastic strip on the inside lip of the lid.
Ribbon cable works very well.
If you break out the turns to a shorting switch you can tune the thing.
And, even the locks and supports for the lid are plastic!
To hide the wraps, plastic molding works super!
To hide the switch, a plastic box like a budd box mounted on the inside works.
To hide the RF connector, use an RCA connector and mark it MP3 speaker.
I use such as an induction coil and Tesla coil. The Model 1882 Wireless Telephone : The Induction Coil Antenna
The advantage of having the loop in the lid is that when open the coil is upright.
The advantage of having it secluded in the lip is that the loop is fully out of the way, the briefcase works as a briefcase, and out of sight is out of mind.
If you are going to use this for a Tesla coil, you will want 2 RCA connectors as one can not stand the voltage.
it does good on loud stations but I'm behind brick and on the lower half of a split level gonna do some thorough testing soon but am unable to set up my gear anywhere i could get a solid read on it for a couple days but everything works and bigger improvent over whip