SMA vs BNC
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jim202
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Depends on what your trying to do. The SMA is made for small cables and tight locations. It is not made to take a bunch of abuse. The BNC on the other hand is made to be easy to take of and on. It can take some abuse and larger type coax cables. Frequency wise, I would take the stand that they are about the same. They will cover the range of frequencies that most people would use for scanners.
Unless you ask a more detailed question, I am done.
The SMA is better at resisting water intrusion than the BNC and is the most popular style connection on most 2-way radios.
For a free-wide connection, such as to an external antenna, yes the BNC is a better choice but it isn;t something that an SMA to BNC adapter wouldn't solve.
For a free-wide connection, such as to an external antenna, yes the BNC is a better choice but it isn;t something that an SMA to BNC adapter wouldn't solve.
WA1ATA
Member
I have handheld scanners with both SMA and BNC connectors. The SMA connector seems much more fragile.
And with an SMA male to BNC female adaptor screwed into the handheld's SMA jack, it seems even more fragile as the adaptor is a lever arm that increases the stress on the connector on the scanner.
SMA has better performance, but without sophisticated test instruments looking at 1GHz range and above, you won't see the difference in practice.
And with an SMA male to BNC female adaptor screwed into the handheld's SMA jack, it seems even more fragile as the adaptor is a lever arm that increases the stress on the connector on the scanner.
SMA has better performance, but without sophisticated test instruments looking at 1GHz range and above, you won't see the difference in practice.
Some additional info...
SMA's can be rated up past 18 GHz, and are usable up to about 25 GHz. They require a torque wrench to REALLY work properly. They're not intended for applications where they are frequently removed.
A good quality BNC connector properly installed can be usable up to around 10 GHz, but in the real world, they're good up to a couple of GHz. Obviously designed for frequent removal, and they're a lot more rugged than SMA's.
SMA's on scanners and radios are there generally because of small size requirements, and not their RF performance.
SMA's can be rated up past 18 GHz, and are usable up to about 25 GHz. They require a torque wrench to REALLY work properly. They're not intended for applications where they are frequently removed.
A good quality BNC connector properly installed can be usable up to around 10 GHz, but in the real world, they're good up to a couple of GHz. Obviously designed for frequent removal, and they're a lot more rugged than SMA's.
SMA's on scanners and radios are there generally because of small size requirements, and not their RF performance.
396XT
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I got an antenna as a gift and its has a bnc connector. On my scanner(396xt), I am using the sma-bnc plug with the antenna. But the antenna is also available in a SMA configuration, so I am thinking if I should exchange for the SMA one or just keep as BNC.
W2NJS
Member
Dump the BNC adapter and use an antenna that matches the radio's native connector. The signal loss you have due to using the adapter is very small, but it still exists, and getting rid of the adapter will also make the antenna stick out less above the radio.
The signal "loss" for the SMA to BNC adapter is a total non-factor. Don't pay any attention to claims that removing it will make any noticeable difference in performance, because it will not.
If you are frequently switching between the rubber ducky antenna and an external antenna, you'll absolutely want to stick with the BNC adapter. The SMA is not designed for repeated and frequent coupling and decoupling, the BNC is.
Also, using the BNC adapter saves all that wear and tear on the scanner's SMA connector. If you ever wear out the BNC side of the adapter, you simply replace the adapter for a few bucks, and the scanner's SMA connector stays in great shape.
Stick with the BNC adapter, bottom line.
If you are frequently switching between the rubber ducky antenna and an external antenna, you'll absolutely want to stick with the BNC adapter. The SMA is not designed for repeated and frequent coupling and decoupling, the BNC is.
Also, using the BNC adapter saves all that wear and tear on the scanner's SMA connector. If you ever wear out the BNC side of the adapter, you simply replace the adapter for a few bucks, and the scanner's SMA connector stays in great shape.
Stick with the BNC adapter, bottom line.
As a hobby machist, I wholeheartedly second Chauffeur6's recomendation. Threaded connections can only last SO long. I have the same scanner as you and put the adaptor on.
Come to think of it, I think it was Chauffeur6 who gave me the same advice!
Come to think of it, I think it was Chauffeur6 who gave me the same advice!
WA1ATA
Member
As I noted above, the disadvantage of the SMA-BNC adaptor is the extra stress it puts on the SMA connector of the handheld. I now use an adaptor, but intend to replace the adaptor with a 12" or 18" RG174 cable, sma male to connect to the scanner on one end, BNC female on the other end.
That way I don't put wear and tear on the scanner SMA connector. A short adaptor pigtail like this is also a good idea when connecting to stiffer coax like RG8/RG6 or LMR400.
That way I don't put wear and tear on the scanner SMA connector. A short adaptor pigtail like this is also a good idea when connecting to stiffer coax like RG8/RG6 or LMR400.
That's fine and well for mobile/base usage where you're always connecting the scanner to an external antenna via coax. It doesn't work for a scenario where you're using the rubber ducky antenna 50% of the time, and an external antenna the other 50% of the time. In that scenario, which is what the OP is dealing with, you'd still need to couple and decouple the SMA connection entirely too much for what it was designed for.
SMA-BNC Adapter
Let's not forget, all adapters are not made the same. The adapter that comes with the XT handhelds is a sturdy piece, so much so I ordered extras for my Home Patrol and VX-6R. Other adapters I've seen on the web (Scannermaster, eBay) are skinny, multi-piece designs that look a little too delicate for constant handheld use. I've been using the Uniden adapters for months without any problems.
Let's not forget, all adapters are not made the same. The adapter that comes with the XT handhelds is a sturdy piece, so much so I ordered extras for my Home Patrol and VX-6R. Other adapters I've seen on the web (Scannermaster, eBay) are skinny, multi-piece designs that look a little too delicate for constant handheld use. I've been using the Uniden adapters for months without any problems.
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