I know you have resolved this, but I think the following info will help in future situations, and you can learn if she can come after you when you move out.
While Federal law directly addresses and regulates the right to install a DBS system, I am unaware of anything in Federal law that addressed the responsibility of the removal of a DBS dish from a house that is rented. The is a rental matter, and what your rights are depends upon which state you are in or what the rental laws are in your city . The state or municipal laws will determine this matter. Many states have laws that heavily favor the renter, including situations like yours. She did knowingly allow you the installation, and there is paperwork to prove this. In most states, I believe that makes its removal HER PROBLEM, not yours. I feel comfortable in saying that a properly installed DBS system does not constitute "damage" to the property for which you can be held liable because she had given you written permission and she was present at the time of installation. If you had installed it without her permission, then she would have every moral right for you to remove it at your expense. Although, I wouldn't be surprised if some cities or states side with the renter even if you did not obtain her permission.
However, if your city has a "rent board" or other such city agency, go to them and seek their advice, They will tell you who's problem it is, and if the landlord is wrong, with your permission, they will take action (usually in the form of a letting citing the law and informing the landlord that they cannot make you pay for it), and you do and say nothing to her in regards to this matter. The agency will be your advocate and you must not make matters worse. You will be protected by law from any further action by her because if she attempts in any way to extract money from you that is not meritorious, that is considered retaliation for reporting her (directly prohibited in many cities that have rent boards), and said govt. agency can take further action against her. If you don't have a municipal agency, check with your county government, and if none, finally, your state government office.
To keep things smooth and not get her angry and to deny her the opportunity to get money from you in some other way, tell her that you need it in writing that she has required you to remove the system, (don't tell her the reason for this is so she can't have a meritorious claim that you damaged the roof without her permission. Oh, yes, if there is damage from the UNinstallaion, she will LIE and say she never told you to remove the dish. I know a lot of landlords and building owners, they lie just as much as the renter lie.), and you could pay for the removal, and once you are out of the house, then report her, and if she was in the wrong, you WILL get a check from her in the full amount that you paid because she will be directed to do so by the agency, and even her own attorney will advise her to just get over it and write the check.
Also, try a free legal clinic. They can direct you and even give you a letter to mail to the landlord. Or, if you know anybody in your extended family or circle of friends who is an attorney, seek their free (yes, some attorneys really do help out some people they know with simple advice or even a letter) advice and, if they advise you she is wrong, some are willing to send a letter to the landlord stating your position. Believe me nothing gets greedy, intimidating people and companies off your back like a letter with a law firm's letterhead. And the government sending them a letter telling to said greedy, intimidating party that they are in violation of the law will often get you a letter of apology (and a check if required) mucho pronto from the said landlord, no matter how insincere the true sentiments may be.
Try the government route, then free legal clinic or someone you know or you know who knows an attorney. But don't expect the private attorney to do more than the letter. After that they do want money.
No, I can't say for other states, but I do know that in California, any of the cabling that is in the house belongs to the "OWNER" of the house; it becomes their property. It is not the renter's to take.
Please, all the best of luck to you. Let us know how it turns-out. You are morally in the right, and I do believe most states would also say that you are legally correct and the landlord is wrong. I can tell you that I know several who have had to go the rental boards here for a variety of reasons and have prevailed. One person I know was intimidated out of over $300, until the agency set the owners straight and the money returned to the renter. Many landlords believe they are in the right and are shockingly ignorant of municipal and state laws governing renter's rights or other laws regarding renting houses.