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SMA connector mating cycles (from personal notes)(just an opinion; we've all got them ;-)



Mythology related to a MAX number of mating cycles seems to be related to a MIN specified in SMA specifications in MIL-C-39012.

When mating typical SMA connectors to 3.5 mm or 2.92 mm precision connectors the cycle specification is significantly degraded.
Manufacturing grade SMA connectors are not defined in the precision connector standard.
However, a "true" SMA manufactured to IEC 169-15 "Grade 0" specifications will mate with 3.5 mm and 2.92 mm connectors with minimal degradation in connector life cycle results.
The pin diameter specification for these "true" SMA connectors is in the same range as the precision 3.5 mm connectors.

The specifications are based on actual test data.
The test results "specify the minimum number of manual connection/disconnection operations of a connector pair under laboratory conditions that will not result in damage�.
"Damage" is defined as noncompliance with any specifications.

Connector Family Cycles
3.5 mm 3000
2.92 mm 2000
2.4 mm 5000
1.85 mm 4000

SMA and 3.5mm are mateable connectors.
The SMA connector is an economical, lower performance interface.
Mechanical tolerances, stability, temperature performance, SWR, repeatability, loss, and wear are all much better in the 3.5mm interface.

Cleaning the threads periodically may result in smoother mating.
See also U.FL connector mating cycles

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

The # of mating cycles for a NanoVNA will be much lower than that of commercial grade connectors for several reasons.

- Low-cost Asian connectors are used to keep the cost down
- Users often rotate the centre pin while tightening which "drills out" the female SMA socket. A telltale sign of this is metal dust on the white dielectric. (photo attached)

I use SMA connector savers on all my NanoVNA and TinySA devices. (photo attached)

Roger

yes ... a short male to female adaptor is a good advice to keep the built-in connectors in good shape ... if worn out just replace :-)

i use a similar thing on my rf explorer (also sma connector)

hopefully those metal chips are from the pin of the plug (scraped off when turning on) and not from the socket

greetz sigi dg9bfc

Am 13.05.2022 um 19:16 schrieb Roger Need via groups.io:

Electrical tape as a 'condom'. Put them in separate places could control mating.

--
KT0TT
Allen Kiddoo

I use a Q-tip dipped in alcohol to remove the particles that accumulate
inside a female SMA connector. As for deformity in the center conductor, I
don't think there's much you can do for that.

Zack W9SZ

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On Fri, May 13, 2022 at 12:16 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

The # of mating cycles for a NanoVNA will be much lower than that of
commercial grade connectors for several reasons.

- Low-cost Asian connectors are used to keep the cost down
- Users often rotate the centre pin while tightening which "drills out"
the female SMA socket. A telltale sign of this is metal dust on the white
dielectric. (photo attached)

I use SMA connector savers on all my NanoVNA and TinySA devices. (photo
attached)

Roger

clean socket AND plug!!

dg9bfc sigi

Am 15.05.2022 um 16:51 schrieb Zack Widup:

On 2022-05-15 17:58:+0200, you wrote:

clean socket AND plug!!

dg9bfc sigi

+1

On 2022-05-15 07:20:-0700, you wrote:

Electrical tape as a 'condom'. Put them in separate places could control mating.
--
KT0TT
Allen Kiddoo

As long as there are no unwanted SMA connectors, I don't want to stick my nose in their personal affairs. ;-)

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua