Grounding is like an old wife's tale. If you ask 3 people what the correct way of doing it are, you will get between 5 and 8 answers.
Maybe the better thing to do is to actually do some homework on the subject. There are numerous threads about grounding on the Internet. The strange thing is they all don't say the same thing.
So lets take a step back and try looking at this from a different prospective. First as the question about is the trailer frame, is it actually grounded. Look around and see if you can find any ground wire from the frame going to a ground rod. If you do find a ground wire, does it have the paint removed from under the ground lug? Was there an anti oxidant grease applied between the frame and the ground lug? Does the ground lug have two holes and both have bolts through them? Reason for the 2 hole lug is that with only one hole and one bolt, they can work loose with it being yanked on or hit by a lawn mower.
Now that you have found or not found the trailer frame grounded or not, lets talk about the "Telecommunications" antenna you brought up the question on in the first place. In the NEC (national Electrical Code) there is a section devoted just to telecommunications antennas. The section says something to the effect that you can have a separate grounding of the telecommunications system and then connect that to the electrical ground. In short, the grounding ring ground around the communications shelter and the ground ring around the antenna system can be tied to the electrical ground. This ground ring is made up of multiple ground rods space twice their length around the ring. All the connections are exothermically welded.
To make it simple, it is a good practice to add a ground rod to the base of any antenna structure, and use surge protection on the antenna transmission line. I would not use anything smaller than a #10 wire. The telecommunication companies use a #2 solid wire for their outside grounds.
The size of the ground rod will depend on your soil. If you have good soil with low resistance, a single 8 foot ground rod should be enough. If you have sandy soil, it may take 20 or more feet in length to get a low resistance ground. It may even require multiple ground rods to get a low resistance ground. The goal that the telecommunications companies look for is a ground that is 5 Ohms or less. If you have to use multiple ground rods, make sure you space them at least twice their length apart.
One other place you could check is your home owners insurance company. Many times the insurance company will have their own guide lines that you should be following. If you have a strike and damage is done, the insurance company might just say something to the effect that you have not followed our guide lines and we are not paying the claim.
I have surge protectors on all my coax cables coming into my radio room. They are all connected to various ground rods as they don't all enter the workshop at the same location.