Quoted:
Th manufacturing plant where I used to work had a screened cage for aligning receivers in the 0.1-500 MHz range. It consisted of a wooden frame covered on both sides of each wall, the ceiling, and the floor with copper screen wire. The two doors were also of framed construction, covered both sides and with brass finger stock surrounding them that made contact with copper trim.
Easy to shield range.
The wavelengths are all pretty large.
The biggest problem is keeping the cage solidly grounded at the larger wavelengths.
You have to be careful the whole thing does not 'pick up' and act as an antenna.
Lots of grounds using wide straps.
A piece of wire has such a high inductance over the upper end of your range it is not a suitable ground.
You need wide straps with few bends.
If you are tuning IFs the signals are also usually reasonably low power.