You haven't told us what type of tv antenna you have, and whether or not you have a rotor. To get San Francisco stations in your area, you must use a rotor as the Sacramento stations and the San Francisco stations are not coming from the same direction. Also, to get the UHF stations from San Francisco, I recommend the Channel Master 8-bay bowtie. It is very common in Sacramento to have separate VHF and UHF antennas as it is fairly easy to get decent reception from San Francisco, Santa Rosa, Concord, Chico, Redding, Reno, and even more, as well as all the local stations. But you MUST have a high-gain antenna with a narrow beamwidth. Otherwise, the local stations will interfere with the distant stations. As in Fresno (where I now live), with a high-gain antenna with a narrow beamwidth, it is possible to get more than one station on the SAME channel, just by turning the antenna. I recommend NOT using any pre-amp at the antenna as the powerful Sacramento stations will wipe out most of the distant stations. Generally speaking, in the Sacramento area good coax cable will work better than twin lead, especially if you are around any electrical interference. Also, even twisted twin line can pick up signals that may interfere with the distant signals. But DON'T have several feet of coax wound up in your attic. Every foot of lead, whether twin lead or coax, adds to signal loss. Generally speaking, the antenna should be mounted as high as possible, although this is not always the case, especially with UHF signals. There is never a guarantee as to what you will receive. As far as using a balum at the antenna (and at the tv if necessary), all balums are NOT created equal. Different samples from the same manufacturer can vary greatly in the amount of signal loss, etc., especially at the UHF frequencies. For the antenna AND balum, I recommend staying away from Radio Shack. In Sacramento, the most popular antennas for picking up San Francisco, are made by Winegard and Channel Master. The BEST UHF antenna you can use is the Channel Master
7-foot parabolic but strong winds can cause problems if the mast is not strong enough. I used the 7-foot parabolic on a 30-ft. mast with rotor and got excellent reception from most of the UHF stations from San Francisco. Second best is the 8-bay bowtie. For more information, read my article in RADIO ELECTRONICS magazine, August 1982, titled HOW TO SELECT THE BEST TV ANTENNA. You should be able to find that issue at a library.