From an article on the subject, seemingly aimed at condo boards and community associations and such.
http://www.neighborhoodlink.com/arti...na_Regulations
"Condominium Restrictions
As for condominium associations, owners can install an antenna on balcony or patio if the patio or balcony is a limited common element, restricted for the owner's exclusive use. Again, installation rules would be permissible and may require that the owner cover the antenna as long as such a requirement does not impair an owner's ability to receive a signal or unreasonably delay or increase the cost of installation, maintenance or use.
When a conflict arises concerning the validity of a restriction, the local government, community association, property owner, or management entity that is trying to enforce the restriction has the burden of proving that the restriction is valid. This means that no matter who questions the validity of the restriction, the burden will always be on the entity seeking to enforce the restriction to prove that the restriction is permitted under the rule or that it qualifies for a waiver.
In light of the rapidly changing technology in telecommunications, it is important for you to stay informed on these types of issues faced both by homeowners and community associations. You can find more information about the FCC rules governing satellites and antennas at
www.fcc.gov.
Note: Condominium boards have the right to prohibit residents from attaching the dish or any appurtenant equipment to the limited common element such as walls or fence boards. Further, the limited common element is defined as the airspace contained within the plan bounded by the top of the fence or railing, meaning that boards may prohibit condo owners from installing a dish above the fence line or through the pickets."
What they're demanding doesn't seem out of line with the OTARD rule, and it doesn't seem (to me) that they're applying it to you differently than to others in the condo building. Keep it within the balcony, don't put any holes in the building, and they'll have nothing to say. It would seem to me, at least. And ballasted flat roof mounts are common.