I designed this for the Spektrum dual-antenna receiver on my QAV250. This was originlly designed to mount behind the Lumenier Vibration Damping Camera Plate on the second set of standoffs. However, there are a number of mounting options that will work (See pics for examples of all 3 options):  1. It can be mounted using the screws on top of the 2nd or 3rd set of standoffs with the screws toward the front or the rear. If you're not using the camera plate, this would be your best option.  2. It can be mounted using the silicone isolators from the camera plate. In this case, the best option is to screw the isolators into the standoffs. This moves the isolators a little further out then they are supposed to be, but they're silicone so it's not an issue. I plan to use the isolators to mount the camera to the quad using the 1st and 2nd set of standoffs. The benefit to this is that you can use the 4 extra lock washers under the front isolators so that the camera won't be angled slightly down. This will level it out nicely.  3. Or, it can actually be mounted underneath the camera mount using the second set of standoffs and the isolators mounted in the slots as they are intended to be mounted. The clearance is kind of tight and I may modify the design slightly to move the antenna tubes outward and give the camera plate a little more room between the antenna tubes.   **EDIT: V2 with slightly wider antenna spacing has been added as an option to the original. This should allow the antenna holder to be mounted underneath the camera plate.  This was designed for 3mm or 1/8" antenna tubes. The holes are slightly out-of-round on purpose (only by .1mm). This allows for a snug fit on the antennas but they can still be easily removed for travel or storage. ***If you print this, please post in the comments and let me know how it fits. The current design is the perfect size when printed out on my printer, but that may not be the case on other printers***