View Full Version : BNC vs. SMA

02-21-2004, 01:11 AM
One HT has a BNC antenna connector. My other has an SMA antenna connector. I wish the radio manufacturers would just use one specific type of connector for the HT's (IMHO the BNC is the best).

Are the SMA's the "newest fad" or are they less expensive? Anybody have any idea why the manufacturers are using the two different types instead of one? I'm getting to where I can't afford one BNC antenna then a SMA antenna, then and adpter for SMA to BNC, then anothe adapter for BNC to SMA.

Garsh! All these letters, sounds like Sesame Street http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

02-21-2004, 02:56 AM
Ha! Just be glad you're not afflicted with the disease I have: Motorola sickness. Every radio uses a different antenna connector (HTs that is) and none of them are standard to anything else. To use an external antenna, one must have the correct "adaptor" which is invariably rather costly!

And the mobiles? They have the famed "mini UHF" connector. I've never seen one on anything else, though it is a good connector.

Yep, it's a sickness alright. What was YOUR complaint again?!

02-21-2004, 03:12 AM
The SMA series connector which will work well into microwave frequencys has been around a long time and is a better, smaller, lighter conector than the BNC. If you want smaller radios then you have to accept smaller connectors. P.S. buy a lot of adapters it will make you feel in control. http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

Terry, K7FE

02-21-2004, 03:25 AM

Ericsson (formerly General Electric and now even something else) used the mini-UHF on their 800 MHz and 900 MHz equipment!

Of course Motorola also used the old "UHF" series on radios for decades, the type "N" on some mobiles, and the BNC and TNC on a few others! On portable equipment they used to be fairly "standardized" with the same basic screw type connector on all "HT" units and the UHF connectors on "PT" units. Of course the old H01ANC and the HO3ANC "two gun" portable receivers used a large type mini-phone plug for an external antenna (otherwise they used an r.f. choke into the battery for the antenna!) and the Pageboy I units had the smaller mini-phone plug connector for the external antenna. Motorola also used the RCA connector on some radios, especially on some of the "CNB" type of "monitor" receivers

Now, on amateur radio equipment there has been the terminal strip (2 and 3 wire types), the UHF, the type "N", the RCA ("phono") connecter (Collins and Heath were "famous" for using the RCA for the antenna connection on their transmitters / transceivers), the ceramic insulator with threaded rod and "nut" connector, the BNC, the TNC, the coaxial connecter that Millen used (don't know the name of it - but it is "different"!), the Amphenol connector that was usually used as a microphone connector, the "Motorola" connector (this is the type that is used on automobile AM/FM receivers - AMECO was "fond" of this connector), the "banana plug" type, and several other (some "really weird") connectors.

Next, there were the FM portables for the amateur radio service! Several of those used some "one of a kind" antenna connector!

At least the same adapter that is made for the Motorola connector also works very well with the RCA connector. It fits inside the Motorola and outside of the RCA. Radio Shack used to have (may still have) these adapters to go between the UHF series and the Motorola / RCA series.

The fact that only two connectors are generally used on the newer amateur radio FM portables is really much better than in days past! I still have adapters laying around to get from the various antenna connectors used on amateur and commercial equipment into my test equipment. Some of these were made by only one manufacturer and were definitely needed to service their equipment.

Glen, K9STH

02-21-2004, 08:03 AM
I just lubed up bent over and spent the money to obtain a varied selection of adapters. Now I just have to remember what adapters I have before I buy. LOL 73's Chris

02-21-2004, 08:22 AM
My experience with the SMA is limited to a few new mini HT's, but I like them.
They are smaller than the BNC
They are more secure, the BNC can pull off in not locked
BNC's need a lot of torque, could be a fastening problem

One possible problem is that the center conductor looks awfully small, wonder how much power it will take for non-HT use?


02-21-2004, 03:55 PM
Tom, K8ERV
The SMA connector is rated to 18 GHZ at 70,000 ft and many manufactures rate them to 25 GHZ. I have powered 40 watts at 2.4 GHZ CCS thru these connectors and I am sure that they would have taken 100 watts, my transistors however would not and began to internally hemorrhage.

The BNC dielectric is rated 1500V and we drive several hundred watts thru them, where as the SMA is rated 1000V. So power up your HT, the only limitation will be your battery.

Terry, K7FE

02-21-2004, 06:09 PM
There are some other connectors that look like a standard SMA, but the center pins are smaller in diameter, and the dialetric is air ( as much as possible ) These are often referred to as a "2.9" or a "2.4" around our lab, depending on how high we are trying to get in frequency. We play with 40 Ghz stuff quite often, and these will go higher than that !

Here is an interesting web page to show you more about the higher stuff. ( frequency = price ! )


73 from Jim

02-21-2004, 07:19 PM
And don't forget the RP-SMAs used on 80211b and other wifi variants. And then there's the MCX (the RF connector equivalent of ZIF) used on some GPS units. It all sounds like a hokey spy movie, or a bowl of cheap vegetable soup.

I'd love to see statistics of how many cellsite components get switched out because less than ZIF was used to connect cables between module stages at the time of manufacture.