Wait a minute,,, Please a more accurate and detailed definition of just what exactly is an Illegal high frequency amplifier? I don't believe that the type of output device defines the description? A 3CX3000A7 device does not by it's own virtue make for a Illegal amplifier. Perhaps certain amplifiers being built and commercially sold for use on unauthorized services or amps being commercially marketed and distributed without FCC Type Acceptance within the jurisdiction of the United States might be considered illegal. I hold a US Amateur Radio Callsign and I operate a US Amateur Radio Station. Amateurs have a long tradition of building and intentional radiating RF devices. It is unique circumstance that a private individual may actually build and operate any type of intentional radiator for their own usefulness without the proper type acceptance and certification of the design and submission of the device for technical inspection. This tradition exists because hams used to provide proof of their proficiency and competency regarding their knowledge of technical theory, standards, best practices along with rules, regulations and proper operating procedures. Such competency was proven through the administration of a test examination where the prospective amateur would demonstrate his competency by providing descriptive solution, reasoning with explaination to each examination question, challenge or example. Hams were tested on their knowledge of Ham Radio, not on their knowledge of Ham Radio Test Materials. The tradition of hams ability to properly build , aquire assemble or operate devices for intentional radiation may soon be a thing of the past. Today we are confronted with devices that are not type accepted for amateur service and regardless of how they are operated are being considered Illegal? Maybe more concern and attention to all the scofflaw that goes on with these import FM rigs? Today there still is the tradition that allows for a ham to build and operate amplifiers based upon whatever surplus or commercial RF device they choose. As long as it is operated in a technically correct and legal manner including it's emmisions and amplitude. If operated beyond such permissible emission, it is not the device but is the operator! BtW .... 3CX3000A7 is an excellent device for ham use. It is inexpensive on the surplus market. It is easy to use with simplistic circuitry, it emits very clean emmisions and it's very hardy. Having alot of headroom assures hardiness and longevity . The grid can dissapate upwards of 400 watts. 100 watts will give you full legal and maybe a little headroom. Who excites an amp with much more than that? So would you consider some of the legal plus amps that are sold with type acceptance illegal too? The Alphas , Henry, OM, ect..... Oh and also export amps? Huh?!