• I saw today's definition and I'm confused and wondering if I'm missing something.


    - Reverse Polarity-Threaded Naval Connector; a connector type unique to Cisco Aironet radios and antennas. Part 15.203 of the FCC rules covering spread spectrum devices limits the types of antennas that may be used with transmission equipment. In compliance with this rule, Cisco Aironet, like all other wireless LAN providers, equips its radios and antennas with a unique connector to prevent attachment of non-approved antennas to radios, however, these ?unique? connectors are no longer unique since is it easy to convert from one type to another using adapters.

    I'm curious why this says the connectors are unique to Cisco? I can think of several other vendors that use this connection and Cisco doesn't exclusively use this connector either. Also, there is no mention in the CWNP Dictionary of the other types of connectors that are used by radio manufacturers. Just slightly confused.

  • Back in the old days, vendors were mandated which connectors they would use by the FCC. This of course has been relaxed for many years but Cisco was assigned the RP-TNC connectors. The FCC did this to make it more difficult for people to construct their own antennas and cables. Of course, the industry responded by making all types of connectors and convertors so anyone could connect any type of antenna to any type of cable and thus to any type of connector on an AP. The FCC gave up on this when Wi-Fi became a mainstream consumer product but you still see many types of connectors (SMA, RP-TNC, N-type, etc.)

    The reason why I included RP-TNC as a definition and not other connectors is because I got so many questions about that connector type in the years before writing the dictionary. I'll try to add other connectors to the next version. Feel free to send me a list of all the ones you want to include, if you'd like.

    Joel Barrett

  • Great explanation, I love tidbits of history like this.

  • I knew there had to be some information that I was missing that would make this all make sense. I don't think you necessarily need to add more to the dictionary. I just wasn't sure why this type was in there but none of the others. I assume that the reverse polarity part kind of went with the wind as well? I thought I read someplace that the FCC required that as well but I could be off on that.

  • NOT! Naval Connector.

    Neal - Concelman. two engineers for Bell Labs who were tasked to develop a secure connector for 25 watts at microwave frequencies. The BNC did not meet all requirements, but it has served us well

    Neal later developed the connector that fit the requirements; the N connector
    Concelman developed the C connector; a BNC on steroids

    BNC: Bayonet Neal Concelman. TNC: Threaded Neal Concelman. No anchor clankers involved

  • Naval or Neal ?

    Personally I go with Neal, but actually you'll find both in the literature. Just know they mean the same thing.

    Getting back to RP-TNC connectors - I've usually found that these have greater losses than RP-SMA (for example).

  • Spent years in the Navy and it was always ?British Naval Connector?, years later took a Qualcomm CDMA course and was duly corrected!
    Joel 1 of the biggest pains I deal with is techs who don?t know a plug from a jack, or RP from non-RP; ?eight-by-ten color glossy photographs with circles and arrows and a paragraph on the back of each one? would do a lot to help explain this stuff to the uninitiated.

  • Years ago I was about a week away from commissioning a satellite earth station in Africa . I got a call that President Clinton would be making a speech during his visit to the capital where we were, and that the media ( NBC etc ) needed satellite access the next day . For a bunch of reasons, other facilities were not available. I told the powers that be that it was impossible. Half the kit was not installed, no testing had been done. They went ahead and booked satellite time for the next morning at 6:30 a.m. Just like that. We worked in a frenzy. Boxes and cables everywhere. Jerry-rigged gear all over the place. No motors on the antenna yet ( a large antenna ). We had to hand crank it to cut the azimuth and elevation patterns. No fun at all. About 6 a.m we had fitted a bunch of modems, up and downconverters and HPAs and had the microwave backhaul link to the press room established. Got permission to radiate and ?nothing. Had about half an hour left.
    Checked everything and found there was no output from the cross site cables to the converters/HPAs. We usually used a very high quality cross site cable, but that wasn?t due to arrive for another three days. Had some old, very high loss coax, but had tons of margin on the modem outputs, so no probs there. Used a spectrum analyzer to check the signals at the input and output of the cable. Good in, next to nothing coming out. Prepared new cable and new connectors. Same thing. Stomach not so good. Paws very sweaty indeed. Loads of calls coming in from Reuters etc to confirm uplink time.

    As I was soldering part of the BNC connector kit, I noticed a piece of metal came off the center pin. We always used very high quality connectors. I took my finger nail and scraped off a another piece. I knew straight away they were fake. Big problem where I worked. Stuff packaged beautifully and with ( nearly always correct spelling ) on the instruction sheets, but made?God knows where. Took a magnifying glass that I had and stuck a pin in the female BNC at the equipment end. Could see a tiny gap between the pin and the receptacle. That was all it took. Loads of attenuation and tons of VSWR.

    Next thought was ?if the cables are fake?that?s it all over? ?..had happened before?.caught that one by reading ?Adndrews Corporation? on the jacket.

    Fortunately they were all OK. Had a bunch of old crappy BNCs at the bottom of my toolbox, but knew that they were genuine. Quickly put them on and managed to get on the air with less than 3 minutes to spare.

    Got two doses of malaria back to back later on. Fake drugs on the first one that nearly did me in. Beautiful packaging, but useless powder in the capsules.


  • [quote]Spent years in the Navy and it was always ?British Naval Connector?, years later took a Qualcomm CDMA course and was duly corrected![/quote]

    which would make the TNC the Tibetan Naval connector?

  • Great counterfeit story there. Mine's not as exciting, but another example of fraud.

    I once bought a Class 1, meaning high power, Bluetooth dongle at the local swapmeet. Nice package, all the right words, logo's etc., no mis-spellings - and at a good price. I had several class 2 models, but wanted one with the higher power.

    Down its side was an external antenna, that you could rotate. The dongle case was a little longer, matching the antenna length.

    Got it home, plugged it in, and loaded drivers without problems.

    However, when I turned it on it got no better reception than either of my old ones.

    So I figured I'd remove the external antenna, and replace it with an RP-SMA connector.

    So I open it up....... and found that the antenna was fake and was just a solid piece of plastic. Behind the antenna mount the case was empty with only a normal sized BT board inside.

    After searching on the Net I found the original compannies website and their story about the counterfeits.

    So now I keep it as an example to show people when they tell me they don't believe that there are fakes out there. No one can believe the antenna - it looks so nice.

    At least it worked somewhat !

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