Outdoor tv antennas are traditionally mounted on a rooftop and have a better line of site to the broadcast towers with fewer obstructions trees buildings walls or roofing materials and they have a distinct advantage over indoor and attic antennas.
Why is outdoor antenna better than attic.
As we old timers will tell you a compromise antenna is always better than no antenna at all.
This is particularly true in a flat housing development with houses that are all about the same height.
If you do have reflective insulation and or something like a concrete tile roof it could make a substantial difference especially for distant or weak signals.
Overall antennas are at best a compromise and sometimes are as difficult to install as outdoor antennas.
If you put an antenna on something like a 10 mast on the roof you usually will clear a lot of obstructions.
Also getting your antenna away from rf noise sources in the house is a good thing.
It is hard to predict the result of putting an antenna in the attic.
Usually priced somewhere north of 100.
If you live a far distance from the broadcast towers a long.
They also cost more.
That might be foil backed insulation metal roofing etc.
On the flip side outdoor antennas are usually placed on top of roofs or garages and are much larger and more powerful than the indoor antennas.
If your roof has any metallic material that s going to be a big issue.
All building materials have some amount of rf attenuation.