Custom, self-constructed and low cost...like everything in our RV. Details with links to all items used are in our below Casita trailer writeup link but I'll cut and paste (without the item links)...but unfortunately it is long...
"We added two Bolt-on Rear Bumper 2 Inch Hitch Receivers on each side of our Casita trailer rear bumper which is a light weight, low cost and non-invasive approach (i.e., they don’t require bolting or welding a heavy rear hitch structure/receiver to the trailer frame) to accomplish his project. Each hitch receiver is rated for 200 pounds of load. It should be noted that 150 pounds is the maximum recommended load to place on the rear of a Casita trailer rear bumper to avoid creating a sway issue and potential accident. One hitch receiver is used for our Internet satellite dish and the other hitch receiver is used for our radio communications antenna when we are stationary and camping. When we are moving and traveling, both these hitch receivers can be used in conjunction with a 2 inch square tube having a 0.25 inch thickness that we welded together to create a third 2 inch hitch receiver located in the center of and 6 inches aft of our Casita trailer rear bumper which can then be then be used to attach our Kuat Sherpa Two Bike Bicycle Rack. It should be noted that older Casita trailers apparently had an inadequate bumper structure to support this approach. The newer Casita trailers don’t have this limitation as they use a 4 inch square steel tube having a 0.120 inch thickness that is already securely welded to the Casita frame.
We added a Hitch Mount Flag Pole Holder to enable using a 20 feet Telescoping Flag Pole and Adapter Bushing to create an Internet satellite dish mast for our Starlink Roam System from our SpaceX Affiliate. In similar fashion, we also created a radio communications mast for our 2 meter VHF and 10 to 80 meter HF radio communications antenna. This arrangement smartly places the entire weight of our Internet satellite dish, our radio communications antenna and their associated telescoping flag poles on the ground instead of using some other weaker and problematic arrangement that would require fastening to the trailer structure. Starlink Roam provides High Speed Internet via a month-by-month subscription plan for emailing/texting, making video phone calls, surfing the Internet, downloading our digital books onto our Amazon Kindle Paperwhites (which negates the need for any reading lights or storing paper books) and 4K streaming our desired HD programming that is then projected via a light-weight, portable, tiny soda-can sized HD Nebula Capsule Projector onto a light-weight and portable 40 inch Tecdigbo Projector Screen that can be easily hung when desired using two Mini Hero Clips that clip to two 6mm bolt/eye nuts installed in the existing roof upper cabinet fastener penetrations. With today's projector and Internet capability, there's absolutely no need to hang bulky TVs or use TV cable/satellite systems anymore...in RVs or in homes. This Bluetooth technology projector is also used as our Casita trailer music sound system. Having a FCC Extra Class radio license (NZ7N), we can also communicate via radio to anyplace in the US or the world using our VHF Yaesu FT-60R Transceiver and our HF Elecraft KX2 Transceiver System via voice or Morse code.
Our Starlink Roam System Wi-Fi router and satellite dish power module were placed in our Casita trailer driver side bench seat storage area and can be powered from either an added 120VAC 20A electrical receptacle outlet which can use shore power, an added Inverter or an added 12VDC 30A SAE power port (please see below for more details on these refinements). The Starlink Roam satellite dish cable is routed out our Casita trailer OEM exterior access hatch in a similar fashion as the shore power cord. This access hatch is also conveniently used as an exhaust fan ventilation path for our custom "cat bathroom" which is located within a custom storage cabinet in our custom mattress sleeping area (please see below for more details on these refinements). So we will never replace this exterior access hatch with a solid panel for using a detachable shore power cord that we would then also have to find an as convenient place to store it."