Is this antenna for FM Radio & how do I connect to it?

I do agree without a yard stick standing next to it hard to tell if it is CB. Ham or AM/FM

Better than a yard stick, a meter stick
FM is the 3 meter band so a quarter wave is about 75cM (3/4 of a meter)

Ham is 2 meter so it's 50cm (half a meter)

Cb will be none of the above. and will have a coil at the base.

If it is an AM/FM it has a standard "Motorola" plug, this is a coaxial plug where the tip is extended beyond the outer shield/sleeve And it's not really designed to attach to a home type radio.> But is to a car radio.. (Which has the matching hole in it.

Most "home" radios will have 2 screws.. You can use a clip from the TIP of the antenna lead to one screw and a second clip lead to ground (Or the sleeve) but frankly that's not the best option. Impedances of the feed line are not anything I'm comfortable talking about.

You can also use a 75 to 300 ohm balun (Transformer) but finding the right adapt-a-connector may drive you bonkers.. I know where to look and even I have issues finding 'em.

It is a AM/FM antenna. IF it is installed on your trailer, then it IS connected to a radio in the RV. They do NOT install AM/FM antenna's from the OEM if they do NOT have a factory installed Radio/Sound System. Doug

It could also be for a CB radio if your RV is a Class A to C.

looks like it may be one like this RV Motorhome Trailer AM/FM Radio Antenna, if you look through the pictures you can see the plug you are looking for it may have to be adapted to work with your radio if it does not have the correct plug in.

I have a antenna like that on my class C it is for the outside radio. You Sony stereo is hooked the same as mine and gets the same results. For music & news I use a smart phone and apps Radio Garden & pandora both are free.

Moved to Tech Issues forum from DIY.

It looks like a ham radio antenna for 2 meters. If you can snap a picture of the base it would really help.

The plug is the same as a car stereo. The antenna is basically a car stereo antenna except made to mount to the trailer roof.

Car antenna cable plug

Should have a coax type cable with a male plug on the end to go into your stereo.

I would expect that ant. to be connected to your stereo. Are you sure it isn't?