Extend the range of your Fritzbox 7590 by two external antennas mounted on these holders.

Supports are included where required. I printed the holders in PLA with a 0.4 mm nozzle at 0.5 mm extrusion width and 0.3 mm layer height.

My Fritzbox 7590 is an early model (article no. 2000 2814 with the thin housing with two rows of grill openings at the gray back).

Later versions of the 7590 have a beefier housing and more grill rows at the gray back. They will require you to modify the parameters

• "d_fritz" (diameter of the gray "drums" at the back of the lower housing half)
• possibly "z_fritz" (horizontal length of the gray "drums" at the back of the lower housing half)
• possibly "bump_pos" to reposition the alignment bump
• possibly "d_antenna" if you are using an antenna with a different base diameter

in the appended OpenSCAD source file:

• Download and install OpenSCAD from https://www.openscad.org
• Launch OpenSCAD and open the enclosed OpenSCAD source file (/File/Open).
• Amend the parameters at the top of the file.
• Save your changes (/File/Save).
• Render the design (/Design/Render).
• Export the rendered design e.g. as a .stl file (/File/Export/Export as STL).
• Slice and print.

The holders may also fit Fritzbox 7530 and 5530 after similar adaptations of the source file, but I haven't verified this, as I do not have access to the respective Fritzbox versions currently.

Bill of materials (BOM):

• One 3D-printed left and one 3D-printed right holder.
• Two 2.4 GHz or dual-band antennas with 90 degree hinge and RP-SMA male connectors. Max. antenna diameter 14 mm.
• Two 25 cm RP SMA female to U.FL IPX patch cables made of the very thin and therefore flexible "1.13"-type cable (the pink RG178 cable will be too stiff), e.g. the "RP SMA female 1.13" variant from https://www.aliexpress.com/item/32806195194.html
• Two to four 2.9 x 9.5 mm self-tapping screws (DIN 7981-C-H) or similar.
• One 2 mm drill to drill holes into the lower (grey) Fritzbox case for the self-tapping screws.

Installation:

• Purchase the materials according to the above BOM.
• Print the two holders. Remove the support "star" inside the SMA mounting hole after printing. Do not remove the 0.5 mm support walls in the row of square holes.
• Open the Fritzbox according to instructions in Youtube.
• Disconnect the tiny IPX connectors of the black and the white cable leading to the two identical lateral PCB antennas at the back of the Fritzbox. I am assuming you to be familiar with the handling of these tiny and delicate IPX connectors. You may leave these cables and antennas in the Fritzbox, but you must isolate the IPX connectors e.g. with electric tape to prevent short circuits.
• Insert the two IPX connectors of the patch cables from the outside through the rear case grill and connect them to the PCB. You may have to spread the grill bars about 0.5 mm with a flat screwdriver to let the IPX connector pass. I am assuming you to be familiar with the handling of these tiny and delicate IPX connectors.
• Reassemble the two Fritzbox case halfs including the five Fritzbox screws.The two SMA connectors of the patch cables are now on the outside.
• Attach the right holder to the lower Fritzbox case, inserting the positioning bump into the case's rear screw hole. Drill one or two holes through the holder's row of square holes into the case, while aligning the holder to the grey "drum" of the case by hand. Insert the 2.9 x 9.5 mm self-tapping screews, tightening them only lightly.
• Do the same with the left holder.
• Insert the SMA connector of the patch cable into the 7 mm hole of the right holder. Tighten the SMA nut from the other side until the hex head of the SMA connector has sunk into the hex recess of the holder. Do not overtighten.
• Do the same with the left patch cable.
• Attach the antennas and fold them upwards.
• That's it !

See my other designs at
https://www.thingiverse.com/thinger13/designs