a chassis comprising a plurality of openings, each opening having chassis-hinge portions on one of two edges of the openings, the chassis-hinge portions removably attachable to the one edge of the two edges;

a plurality of modular doors, each of the plurality of modular doors comprising:

an outside surface having a first edge, a second edge, and a third edge;

an inside surface opposing the outside surface; and

door-hinge receptacles on at least the first edge and the second edge of each of the plurality of modular doors, the door-hinge receptacles to receive door-hinge portions,

wherein each door-hinge portion positioned in a respective door-hinge receptacle on one edge of the plurality of modular doors is configured to mate with a respective chassis-hinge portion on the one edge of one of the plurality of openings, wherein the mated chassis-hinge portion and door-hinge portion form a hinge to rotatably attach the modular door to the one of the plurality of openings adjacent to the mated-chassis-hinge portion, and wherein the modular doors are orientable in either a third-edge-up position or a third-edge-down position; and

at least one radio frequency system comprising:

a plurality of electronic components operably attached to the inside surface of at least one of the plurality of modular doors, wherein the at least one radio frequency system operates over a range of frequencies.