Ham Radio: Interference / BPL

This article (book?) introduces common-mode chokes, why they are used, how to make common-mode chokes for HF, selecting ferrite components, noise sniffing, a 4:1 current balun, difference mode power line filters, and more.

How to choose ferrites for EMI suppression, ferrites for various applications, ...

Filter Concepts is a source for EMI filters for AC and DC applications.

Gene Preston K5GP has tracked down many RFI powerline interference issues in his career. In this article, he explains the tools needed and process to find and fix these annoying issues which can greatly hamper ham radio operation.

N0RQ site devoted to finding and eliminating noise sources that interfere with ham radio operations coming from power lines. Guides to finding noisy poles, videos on identifying noisy poles, contacting local utilities and more.

PRB-1 document from the FCC. This is the controversial FCC ruling from 1985 stating that local regulations that restrict ham radio installations are against the interests of the FCC. In particular:

25. Because amateur station communications are only as effective as the antennas employed, antenna height restrictions directly affect the effectiveness of amateur communications. Some amateur antenna configurations require more substantial installations than others if they are to provide the amateur operator with the communications that he/she desires to engage in. For example, an antenna array for International amateur communications will differ from an antenna used to contact other amateur operators at shorter distances. We will not, however, specify any particular height limitation below which a local government may not regulate, nor will we suggest the precise language that must be contained in local ordinances, such as mechanisms for special exceptions, variances, or conditional use permits. Nevertheless, local regulations which involve placement, screening, or height of anatennas based on health, safety, or aesthetic considerations must be crafted to accommodate reasonably amateur communications, and to represent the minimum practicable regulation to accomplish the local authority's legitimate purpose.6

26. Obviously, we do not have the staff or financial resources to review all state and local laws that affect amateur operations. We are confident, however, that state and local governments will endeavor to legislate in a manner that affords appropriate recognition to the important federal interest at stake here and thereby avoid unnecessary conflict with federal policy, as well as time-consuming and expensive litigation in this area. Amateur operators who believe that local or state governments have been overreaching and thereby have precluded accomplishment of their legitimate communications goals, may, in addition, use this document to bring our policies to the attention of local tribunals and forums.

RF Noise Identification. A collection of noise sound files to help ham radio operators identify and eliminate RF noise.

RJ & US IMPORTS has good articles on baluns, ferromagnetic cores (as used in ham radio applications), selecting core material for ferromagnetic applications, toroid sizes, data tables, winding toroids, line filters and chokes, baluns and rods, and steps to eliminate RFI.