What’s this coax jumper wire for ?

[Ronjohnson]

What is this short coax jumper for ? Jayco 19XUD

[craigav]

I don't think my Jayco has that loop. However, my previous other brand RV did and the purpose of it was for using items such as a cable TV box, or DVR\VCR, SAT box inline with the antenna coax prior to connection just to the right which powers the antenna amplifier, and these devices need to be in the loop prior to the antenna power injector. For example if you went to an RV park and they said you need this cable box to get cable, then the top connection is the input for the cable box and the lower connection is the output for the cable box and all tv's would get the same channel. I don't know how common that is anymore, but I think some RV parks still require cable boxes. ~CA

[Iraqvet05]

You remove the loop cable if using a satellite dish and receiver.
Some trailers had a label explaining this.