Probably many more available than you would think! Most dishes are installed out of public view on flat roofs and in the rear access areas of the buildings. Managers don't seem to want to make decisions regarding disposal of unused technology. Often they don't know if the equipment is owned, leased or if the gear is to be recovered.
Unless you are a tradesman, most facilities will not permit access to the roof. This certainly makes it more difficult for a hobbyist to remove. You should contact a few local commercial installers/technicians. Often they will or have removed unused / abandoned gear as a favor or value-add service to the business or property manager while performing other work. If they know that there is a Franklin ($100) in it for them, you might have more dishes and NPRMs than you will ever need!
Keep an eye out for service stations or stores that are rebranding. Usually the brand requires new POS terminals and reporting services. The old terminals are removed and if they remain satellite based, installers typically are instructed not to reuse dishes or mounts.
