I guess I can bring this up on this list as well. 15.203 (not .23, but .203), talks about External Power Amplifiers AND Antennas and subsection (c) is what some people think stops people from mixing and matching antennas on certified radios.
Keyword is "AND". If you read 15.203 sections a-c with the word OR in the title, instead of AND, then it would more closely follow some of the "other" interpretations out there. I respect everything that Tim Pozar discusses and I think I agree with him on just about every issue, except for this one particular issue (swapping of antennas). I think its in how you read the rules and the fact of the matter is, especially after so much disagreement on what it actually means, that the rules really need to be more explicit so we can put this issue to rest, once and for all. My interpretation is that antennas may be swapped, so long as you are NOT using an amp, up/down converter or any other similiar device, just the antenna and radio itself, so long as that radio has already been certified for use by the manufacturer, even if its only been certified with a single antenna. It basically means that the radio itself (digital device) conforms to the equipment authorization requirements set forth by the FCC. Changing the length of coax, or even a bad connector can cause a device to emit noise. But those issues are not intentional. Using an antenna that is "better" or of higher quality, than the stock antenna supplied with the radio, should not be illegal, so long as you are in good faith technical compliance with the rules (ie, not exceeding EIRP limits, doing your best to utilize antennas that will give you directional gain with low sidelobes and F/B ratios in order to keep the transmissions your emitting to the lowest possible levels). If it is illegal in the eyes of the FCC, in multiple years, I've seen not one well documented case of someone failing to comply with the rules if they were not using an amp. Any case that I have seen, has been a case for some other reason (ie, amps were used, the person was intentionally interfering, or both, or some other circumstance). If the FCC didn't want someone to swap antennas, they'd save everyone a whole lot of time, if they documented one public message on the subject. Some kind of official FCC stance on the issue, other than just the rules themselves. If that means a documented case, great, lets see it. If that means an official letter from the appropriate officials, then why not make it happen? This would clear up the confusion and push people in the direction to conform. But this has not happened. The FCC is almost always hands-off, because, what I sense, is that they want to allow for the technology to advance, grow and for users of the technology to be able to expand and utilitize the spectrum that they've allocated for "unlicensed use". The FCC wants to enable, not stifle. The FCC gave us something, said, here you go, make something with it. We'll be here, watching, listening, but we want to avoid driving you in any particular direction, except where you may interfere with other users of the same spectrum, because we are here to oversee that everyone is able to make "fair use" of the "limited" spectrum available. If tomorrow brings new technologies with more efficent ways to utilize that spectrum, they are more than happy to revise or rewrite the rules (UWB is a great example). The FCC knows whats happening, they aren't turning a blind eye, nor are they going after WISP's or home operators who are sharing service with their neighborhood and the rest of urban or rural america. Unless there is some kind of bad faith abuse of the spectrum, then they comment and/or act. Its rare that they have to comment or act, because the huge majority of operators out there, are working in good faith, to build networks and/or businesses (which benefit the economy in so many ways). Also, the FCC being the large organization that it is, the interpretation of one person within the FCC may be much different than the interpretation of another. This is why, "if there is an issue" (I don't see an issue, personally), then there needs to be an official stance, by the FCC, on the subject of swapping antennas in 2.4Ghz and 5.8Ghz or unlicensed spectrum in general. "If this was an issue", I'd can see a large number of very creative and intelligent people, put out of work and on the streets, because their businesses would not be meeting compliance rules. This doesn't just mean WISP's or small operator networks, but also manufacturers and many employees of those manufacturers as well as many international corporations who staff employees who build the radios and antennas that so many people use, every day. Anyway, I'll leave it at that. No more FCC discussions from me. Jeff King wrote: > Would you also need to mine the silicon for the transistor's and carbon for the > resistor's to be compliant with 15.23? > > Until and unless you have a written ruling, it is up in the air. The unnamed > friend of a friend, or my buddy at the FCC is not a ruling. If your not > marketing the device, 15.23 says your free to experiment with it as long as you > are in good faith technical compliance with the rules. > > Quoting Tim Pozar <[EMAIL PROTECTED]>: > > > 15.23 Home-built devices. > > > > (a) Equipment authorization is not required for devices > > that are not marketed, are not constructed from a kit, and > > are built in quantities of five or less for personal use. > > > > (b) It is recognized that the individual builder of > > home-built equipment may not possess the means to perform > > the measurements for determining compliance with the > > regulations. In this case,the builder is expected to employ > > good engineering practices to meet the specified technical > > standards to the greatest extent practicable. The provisions > > of 15.5 apply to this equipment. > > > > Of course 15.5 refers to "Thou shall not interfere and thou shall > > accept all interference". > > > > It seems to me that this section refers to equipment that is not > > already certified since any equipment that is "marketed" needs to > > be certified. Even "kits" need to be certified (15.25). When I > > have talked to others "knowledgeable" in equipment certification, > > they seem to have the same interpretation. It sounds as if using > > an AP that is certified would not be allowed to be mixed and matched > > outside of its certification. > > > > If applied to what we are doing, it would seem that we would have > > to develop our own SS radios and antennas to take advantage of > > 15.23. > > > > Tim > > -- > > general wireless list, a bawug thing <http://www.bawug.org/> > > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
