If it is related to the belt, the frequency will change with engine speed but not road speed.
If you have wheel covers or trim rings, those can squirm around from the wheel flexing as it rotates. Remove them as a test, and if the noise is gone, a very light film of grease will stop the noise.
Wear indicators on brake pads will squeal, and in some applications the squeal will stop when the brakes are applied, and some will squeal when the brakes are applied. In some applications braking has no effect on the squeak.
A warped brake rotor can cause the caliper to slide back and forth on its mounting pads, and that can set up a squeak. Typically that will stop during braking.
Also consider that Ford has had a real lot of trouble with steering and suspension parts separating leading to loss of control and crashes, but that is almost always preceded by a clunk, rattle, or squeak. Large movements often reduce the tendency for those squeaks to be heard. That is typical of bouncing over bumps. What is less-known is almost all tires have sidewalls made of rubber that cured unevenly and as a result they have a softer section and a harder section. As the tire rotates, the harder area flexes less so it pushes the axle up a fraction of an inch. That very tiny movement can allow squeaking to occur between parts. That is most likely to occur to ball joints and to badly worn control arm bushings. Both of those will be found during an inspection at a tire and alignment shop. That should be done at least once per year, and anytime you hear a new noise. This would be a good time for a brake system inspection too.
There are other ways to locate the source of the noise, but for now we need to rule out safety issues.
Sunday, October 9th, 2016 AT 10:35 PM