Is there anything I can do about local interference?

If you live in a populated area, you are likely to be victim to any of a thousand sources of local static interference. It doesn't take much interference to mask the subtle signals from Jupiter. If you cannot locate and root out the interference at its source, you can still sometimes prevail by using a noise canceling device. A receiver with a noise blanking circuit is usually quite expensive, but is quite effective in eliminating spike type interference, (and unfortunately, possibly S bursts). Using  a directional antenna which has a high rejection in other than the intended direction is helpful. As a last resort you may have to take your equipment somewhere which is not so electromagnetically polluted.