Two most common antenna interface: SMA and TNC. The external wireless antenna looks like a similar look, but if you look closely, you will find that they have very different antenna interfaces. If the newly purchased external antenna does not match the radio interface, you will not be able to use it properly. Below we will introduce the two most common antenna interfaces, one called SMA and the other called TNC. SMA antenna interface The full name of the SMA antenna interface is the SMA reverse polarity male (SMA RP M). It can be divided into SMA and RP-SMA according to the difference in polarity. The difference between the two is that SMA means "outer helix + hole" and "inner helix + needle" design; while RP-SMA means " outer spiral + needle" and "inner spiral + hole" design. TNC antenna interface The full name of the TNC antenna interface is the TNC reverse polarity male (TNC RP M). It is thicker than the SMA male, and there is a metal shield between the outer and inner contact points of the antenna connector. Remedial measure: If we forgot to look at the interface type of the antenna before, what should we do if we bought the wrong one? Don't worry, we can buy an interface adapter that converts SMA to TNC or TNC to SMA. Note: Although there are remedies, we strongly recommend that you check the antenna interface type in advance, because using the interface adapter may have an impact on radio performance.
Great comparison! The TNC connector is dimensionally identical (internally) to the BNC connector (except one is threaded and one is "Bayonet" type) Both were named after the designers, and named Bayonet Neill Concelman, Threaded Neill Concelman They were patented by electrical engineers Paul Neill, Carl Concelman. Wikipedia actually has great pages on them complete with dimensions etc. (Neill also designed the N-connector) https://en.wikipedia.org/wiki/BNC_connector https://en.wikipedia.org/wiki/TNC_connector https://en.wikipedia.org/wiki/N_connector BNC and TNC connectors are not even dimensionally close to the SMA, at almost twice the diameter of the SMA. They (SMA connectors) do of course have real Amateur Radio uses I suppose, since manufacturers of some SDR equipment place them on some of the equipment they sell. This forces the user to either buy a rather expensive adapter or a cable. It would be nice if they put the more common (for the average Ham) BNC connector on this equipment since BNC connectors and adapters are very widely available new and surplus for little cost. Cheers, Rick
The abbreviation "RP" really means "Reverse Pin," not "Reverse Polarity." (The connectors do not have a designated polarity, and in fact most often carry AC signals.) Which makes it easier to remember which ones are "reversed;" the connector with the outer shell normally has a pin. The TNC is an improvement on the BNC and has less loss at upper microwave frequencies.
The RP connectors were created when the FCC decided it would attempt to enforce Part 15 EIRP limits by making it difficult for consumers to attach a higher gain antenna to a device. For awhile there, it became the "Ministry of Funny Connectors," trying to make each vendor come up with something unique and incompatible. After awhile, it realized that it was putting an unreasonable burden on manufacturers and stopped doing this, leaving us with several "standard nonstandard" connectors. These include the various RP versions of the TNC, BNC, SMA connector, and N connector.
To help to correct this thread , by adding more info , relative to the issue of frequency of operation between SMA & TNC . Then also is power handling . https://www.amphenolrf.com/frequency-range-chart/
I never seen a SMA that even came close to a TNC. A TNC is closer to a BNC. The sex got screwed up along the way.
Personally, I wish that there were a bayonet connector like the BNC which offered the bandwidth improvements of the TNC and the water resistance of the N connector. Threads, a machine meant to provide mechanical advantage (which you hopefully do not need to seat a small connector!), are a pain in the posterior; they come loose and or stick at inappropriate times. Bayonets provide a positive connection that requires movement in two orthogonal directions - but not much force - to undo.
TNC connectors were very common in old style mobile phones from the 80s and 90s. They are also used on some mobile lmr equipment, and some handheld radios. They are an excellent connector, and really should be first choice for most mobile radios. Better RF wise than PL259 or BNC, smaller form factor than type N. More robust than SMA. TNC doesn't get the love it deserves.
https://www.amphenolrf.com/connectors/c-type.html C-TYPE CONNECTOR SERIES The C Type series is a weatherproof medium size series. The series features a coupling two-stud bayonet lock.It has a constant 50 Ω impedance and performs up to 11 GHz. However, it may be used with 75 Ω cable at lower frequencies (below 300 MHz).
The OP is not even talking about HR equipment, since it talks about the RP type connectors, which are never used in HR. It actually applies more to WiFi equipment. That said, TNC are not uncommon in two way and home routers, pretty scarcely used in HR stuff.
