I picked up this $40 SDR (this should work with the V4 version as well) on Amazon to try and download some satellite images from NOAA satellites going over head. Based off the image below, the configuration of your V-dipole antenna should have them 120 degrees apart, and set to the appropriate lengths.

Rather than using a protractor, I designed this two-halve case that makes sure the antennas are held exactly 120 degrees apart. This makes it impossible to not have your antenna not at 120 degrees. The only thing left to do is make sure the antennas are extended to 52cm.

To help get the antenna lengths easier, I added a notch on each side to help keep a tape measure in place when measuring.

There are also two pieces that extrude off the top to help easily take the case off, simply push on them to remove from the antenna base.

The case should fit snugly, in my case, its snug enough to easily get on/off, and will stay on even if you were to drop or shake it.

Let me know if you have any more suggestions!