Why do people hate SMA antennas?

[Rred]

Henry, the SMA connection is designed to be a cheap high efficiency connection supposedly for "internal" use, i.e. between two components in one housing. Assemble once and walk away, never used again unless repairs are being made.

So for handhelds, which only need "final assembly" of the antenna once when it is put in use, or for WiFi routers, again needing assembly only once when they are put in use, it is perfectly sensible.

If you plan to abuse it by swapping out antennas the threads will cross and you will have problems. Most users can't get that through their heads, this is not how the SMA is supposed to be used. You might as well complain that the h/t does not work very long when you use it as a hammer. Well, duh, it ain't supposed to be used as a hammer!

You can spend about $10 to but a simple SMA-to-BNC adapter that screws firmly onto the SMA of your radio. Slip a small o-ring under it is there's any gap that might let water in. Use a tad of thread lock if you have a problem with it coming loose. (Shouldn't need it.)

Then just buy BNC antenna's and cables, and one little twist gets them on and off, many many times. Which is what the BNC is designed for. That's the right way to do things.

Or, you buy an SMA (or BNC) pigtail, a foot of thin coax that has a PL-259 or SO-239 on the other end. And you use the pigtail when you want to hook up to a standard antenna cable with a big ugly connector on it. Stain relieve that pigtail's flimsy cable by looping it around the battery clip of your h/t, or some other way, because that thin cable also is not meant to be very robust, it is meant to make sure that a bigger cable doesn't stress and damage the SMA stub installed in the h/t.

 

[jdavidboyd]

Here's a tip when preparing to screw anything: Carefully turn slowly in the opposite direction until you feel a tiny bump, then gently reverse direction. The bump you felt were the threads lining up.

Nooooo, that's a "secret"!

Sent from my VS986 using Tapatalk

 

[prcguy]

An actual SMA is a very robust microwave connector intended for use up to 18GHz and not designed just for "internal" use. There are millions of them externally on microwave equipment and much of it designed for outdoor use and lots of connect/disconnect cycles.

Its small size is not to save space, but to allow operation to 18GHz and even 40GHz in some versions without the coax or connector operating in a TE or TM (waveguide) mode due to the spacing of the center conductor and inside shield being too large, allowing multiple modes of propagation.

The Chinese versions that have come on the market in the last 20yrs are not good to 18GHz and are made of cheap materials that wear out faster than the stainless steel and heavy gold plated brass or steel versions I've been using for the last 35yrs. They have become more of a consumer grade connector and not a specialized commercial/military connector.
prcguy

Henry, the SMA connection is designed to be a cheap high efficiency connection supposedly for "internal" use, i.e. between two components in one housing. Assemble once and walk away, never used again unless repairs are being made.

So for handhelds, which only need "final assembly" of the antenna once when it is put in use, or for WiFi routers, again needing assembly only once when they are put in use, it is perfectly sensible.

If you plan to abuse it by swapping out antennas the threads will cross and you will have problems. Most users can't get that through their heads, this is not how the SMA is supposed to be used. You might as well complain that the h/t does not work very long when you use it as a hammer. Well, duh, it ain't supposed to be used as a hammer!

You can spend about $10 to but a simple SMA-to-BNC adapter that screws firmly onto the SMA of your radio. Slip a small o-ring under it is there's any gap that might let water in. Use a tad of thread lock if you have a problem with it coming loose. (Shouldn't need it.)

Then just buy BNC antenna's and cables, and one little twist gets them on and off, many many times. Which is what the BNC is designed for. That's the right way to do things.

Or, you buy an SMA (or BNC) pigtail, a foot of thin coax that has a PL-259 or SO-239 on the other end. And you use the pigtail when you want to hook up to a standard antenna cable with a big ugly connector on it. Stain relieve that pigtail's flimsy cable by looping it around the battery clip of your h/t, or some other way, because that thin cable also is not meant to be very robust, it is meant to make sure that a bigger cable doesn't stress and damage the SMA stub installed in the h/t.

 

[Dahwg]

The moral of the story.... Hurry up and buy the mobile rig already.

Sent from my LG-H918 using Tapatalk

 

[robertmac]

Most of the portable scanners and transceivers I continue to use today have sma. Most have been dropped more than 6 times onto cement and have never had a problem with male sma on transceivers.

 

[Rred]

Cell phones now mainly use micro-USB connectors. They used to use mini-USB connectors.
But the mini-USB connector was only designed for 500 insertion cycles, so plugging a phone in every night to recharge would theoretically destroy the mini-USB connection in less than two years.

Micro-USB is supposed to be designed for 10x more cycles. And yet, oops, because most of us can't see or feel if it is upside down (there's a widely ignored standard for that) we jam them in and break them more often than the old unreliable mini's.

Same thing with SMA connectors. What they were designed for, and what they are actually used for, are two different things. If it works for you, great. Some people never strip screw threads, others don't have the same gentle touch.(G)

 

[Dahwg]

Cell phones now mainly use micro-USB connectors. They used to use mini-USB connectors.
But the mini-USB connector was only designed for 500 insertion cycles, so plugging a phone in every night to recharge would theoretically destroy the mini-USB connection in less than two years.

Micro-USB is supposed to be designed for 10x more cycles. And yet, oops, because most of us can't see or feel if it is upside down (there's a widely ignored standard for that) we jam them in and break them more often than the old unreliable mini's.

Same thing with SMA connectors. What they were designed for, and what they are actually used for, are two different things. If it works for you, great. Some people never strip screw threads, others don't have the same gentle touch.(G)

I think just being aware that the possibility to damage the antenna and/or the radio exists, should make one more cautious when swapping the antenna out. I know I've become doubly so since I made my original post.

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[KF8ZR]

From a radio standpoint it could be that for the longest time, BNC female was the connector on the hand held radios. You could easily switch out an antenna, connect an external, do testing, etc. When SMA starting getting put on radios, you'd have to get an adapter to go back to BNC or just use a dedicated SMA antenna. Even the smallest handheld radios, Yaesu VX-2 VX-3 Icom _7, etc. were still big enough to have a BNC connect mounted on them . So without the quick release option it became tedious. That's the best reason I could think as to why.

 

[Rred]

PL259/SO239 were designed to be physically robust and capable of hundreds or thousands of uses without problems like cross-threading delicate threads.

SMA was designed to be used "once" to assemble different high frequency sub-assembly boards inside of a chassis box. They are easily cross-threaded. Yes, you can use them more than once but they were just designed to be used once on assembly, maybe two or three more times on troubleshooting....but they were simply not designed for reliable fast repeat use, like BNC or UHF connectors were.

Use them long enough, you will have a cross-threading problem.

You can pick up the groceries or run to the 7-11 in your Ferrari, the car certainly can do the job. But sooner or later....the maintenance bill will make you rethink whether you should have taken the Chevy.