Antenna connecter usage

[WSKY567]

Hope folks don't find this annoying, but it's bugging me.  The antenna connectors, PL259 and especially the SMA, will they expand and start to make poor contact from being plugged and unplugged many times?  I keep all of my radios in some kind of case or pouch.  These cases and pouches can't accommodate a radio with the antenna connected making it necessary to remove the antenna.  I'm wondering if I should avoid the practice of connecting and disconnecting antennas to preserve the integrity of the connection.  

[RoadApple]

I've no scientific evidence on this question but here is my thought.  NO

Connecting and disconnecting the PL259 or SMA connector over and over probably does, at some level, cause the metal to wear down, and over a prolonged period that could impact the connection quality.   My guess is that you probably wouldn't, in your lifetime, connect and disconnect enough times that it would really make a difference in terms of wearing down the metal.   The PL259 is pretty solid so I would not worry about it.  That said, the SMA could be fragile, and you are far more likely to accidently bend or break the inner wire of connector by repeated connections.  

[SteveShannon]

28 minutes ago, WSKY567 said:

Hope folks don't find this annoying, but it's bugging me.  The antenna connectors, PL259 and especially the SMA, will they expand and start to make poor contact from being plugged and unplugged many times?  I keep all of my radios in some kind of case or pouch.  These cases and pouches can't accommodate a radio with the antenna connected making it necessary to remove the antenna.  I'm wondering if I should avoid the practice of connecting and disconnecting antennas to preserve the integrity of the connection.  

No, they won’t expand and start to make poor contact. They can wear though and it’s not a bad idea to lube the threads of the connectors.  Some people (including me) place a BNC adapter on the radio and leave it on the SMA permanently. That requires that you also replace your antennas with BNC antennas which can cost .  But if the BNC connector wears out you just replace it. But honestly, having converted one of my radios to BNC, I really don’t think it is worth it  

 

 

[docholliday666]

All connectors have a mating cycle rating by the manufacturer. Some connectors are designed to last longer (usually nickel plated), others are more limited (gold plated). Spring connector points (like the center pin in BNC) will get weak from excessive cycles and that can cause slight resistance changes, usually when under high current loads. For low power, you'd probably never notice. But for higher power, you may see some arcing or surface burns if the contact gets a weak point. Also, the plating wears off and that can induce oxidation on the base metal.

Slight burrs in the manufacturing can cause premature wear too. Nickel connectors actually have a harder plating so they typically last longer. However, the issue is that nickel also oxidizes easier so gold plating was added to consumer electronic connectors to prevent this. In the pro audio world (not audiofools), nickel is the preferred plating. However, it also requires a cleaning discipline to wipe connectors often.

The best thing to do is to be sure that the connector points are lubricated if you plan on doing a lot of connection/disconnection. In the electronics/sound world, DeOxit Red works great to preventing premature wear and galling of the plating surface which also reduces oxidation in moist environments and makes the connectors last longer.

Sacrificial connector/adapters are also nice, but add length to the stack. Some antennas, like Smileys, have the replaceable connector end, so that makes for a serviceable assembly if the connector started getting worn or loose.

[WSKY567]

Thank you folks for the answers.  Thought about your answers and more about exactly how I would use the radios in question.  I have come up with a solution.  I ordered some cotton drawstring bags that the radios can fit in with the antennas outside of the bags.  They can then fit in a backpack and be protected.  This way the radio surfaces will not get scratched.  Sundry "stuff" can lay loose in the backpack.  

[docholliday666]

I tend to avoid cotton bags as they hold moisture and can mold. I usually use things that can be dessicated or are polymer based to avoid the moisture.

As far as the antennas go, I'd suggest getting some drill bit tubes (McMaster: https://www.mcmaster.com/products/drill-bit-tubes/). They slide open/closed with notches to stop. They'll 1) keep the antennas from being banged or bent, 2) keep the connectors free from lint or dirt, and 3) makes it easier to find smaller antennas so they don't disappear into the bottom of a bag.

[WRUE951]

By  the time you would wear out the connector and I doubt you would, you would be ready for a new radio.. 

[WRYT601]

PL-259s last a long time.  SMA, not so much.  Try to not let the center pin rotate in the connector as that accelerates wear.  I recommend getting decent port savers for things like test gear that see a lot of cable changing.  There are cheap ones, and there are good quality ones.  For a radio that you don't expect to unhook often, the cheap ones are ok, but for things like a nanoVNA, definitely shoot over to RFParts or another reputable vendor and get some decent quality ones.

[HHD1]

sma to bnc adapters

put one on each antenna and each radio for quick and easy antenna swaps and storage.

I also use pl259 to bnc adapters too.

[WRUE951]

3 minutes ago, HHD1 said:

sma to bnc adapters

put one on each antenna and each radio for quick and easy antenna swaps and storage.

I also use pl259 to bnc adapters too.

I remember the older Kenwoods used BNC connectors, they were awesome. Don't know why they switched to SMA. 

[WSKY567]

Another idea:  I use poster tubes for targets and the radios will fit inside of them.  They are waterproof and plenty long.  Not expensive and would protect the radios during transport.  

[HHD1]

2 hours ago, WRUE951 said:

I remember the older Kenwoods used BNC connectors, they were awesome. Don't know why they switched to SMA. 

My first guess is because that's what everyone else uses.  But maybe also for a more weatherproof connection for IP67 rating. Maybe, IDK. I haven't seen a watertight BNC.  But that would be cool.

My opinion is that all portables should have BNC

[WRUE951]

3 hours ago, HHD1 said:

My first guess is because that's what everyone else uses.  But maybe also for a more weatherproof connection for IP67 rating. Maybe, IDK. I haven't seen a watertight BNC.  But that would be cool.

My opinion is that all portables should have BNC

The typical BNC Connector is not waterproof but is water resistance which would meet most radio water resistance requirements.  .   There are BNC Connectors available that rare rated waterproof.  

[docholliday666]

32 minutes ago, WRUE951 said:

The typical BNC Connector is not waterproof but is water resistance which would meet most radio water resistance requirements.  .   There are BNC Connectors available that rare rated waterproof.  

Amphenol makes IP67 rated BNCs. They're pretty much all I use for BNC work.

[docholliday666]

The typical connector, including the PL/SO 259, BNC, and TNC are usually limited to around 500 cycles before they are considered worn out of spec. Most people also don't know that USB (including USB-C) is typically only around 200-300 cycles before the plastic insert separator starts to get worn and causes contact tension errors. 

BTW, you do know that the PL259 (even the nicest Amphenol ones) are frequency limited to somewhere in the 100-350Mhz range before they start causing reflections and other errors in the connection, right? They may be fine for CB and hammers, but are not good for anything in GMRS if you are wanting to reduce error points and get the most out of your signal. I don't even want to know what the knockoff, barely-in-spec Amazon connectors rate. Some of them are out-of-spec when you get them and can actually cause damage to the good connector it's mating with (overspreading spring-loaded contacts, ablating insulators, paint/coatings too thick causing wear, coatings causing resistance, etc).

I've just fixed a laptop that somebody shoved a cheap Amazon HDMI cable into - the plastic moulding was too small and shoved the whole HDMI insert out the back of the plug, ripping every trace off the motherboard. That's what happens with the knockoff stuff. I'll use a CCR anyday, but I'll replace plugs, mics, and other components that are pure trash first.

TNC, BNC, SMA, and MMC were all created for the higher frequencies, hence why you'll never find a PL/SO connector on any high-end diag gear.

[WRUE951]

11 hours ago, docholliday666 said:

 Most people also don't know that USB (including USB-C) is typically only around 200-300 cycles before the plastic insert separator starts to get worn and causes contact tension errors. 

 

Four years ago this was a question that came up around a lunch  table..  How long will a USB connector last?   Somone in the group google it it and came up with an answer that USB connectors will last upto 20,000 inzertion/extraction cycles.  That was 4 years ago,,  I bet today the smaller C type USB's will last much longer. 

[gortex2]

worring about connects on cheap junk radios is not worth it. The conenctor will outlast the radio. just use it. 

[WRUE951]

1 hour ago, gortex2 said:

worring about connects on cheap junk radios is not worth it. The conenctor will outlast the radio. just use it. 

And that same radio will be cheaper  than replacing connectors.  

[docholliday666]

6 hours ago, WRUE951 said:

Four years ago this was a question that came up around a lunch  table..  How long will a USB connector last?   Somone in the group google it it and came up with an answer that USB connectors will last upto 20,000 inzertion/extraction cycles.  That was 4 years ago,,  I bet today the smaller C type USB's will last much longer. 

Don't trust everything you Google...but you can believe that all you want. I'll read the manufacturer specs and even then, that assumes that the plug is inserted perfectly straight with no shear or stress. Plus, the hundreds of plugs I've changed out in the last 4 years says otherwise.

However, the higher end new-gen USB-C connectors (designed for USB 3-4 or TB) do have some 10-30K cycles. They were designed to do so as they are expected to replace all other types. 

[WRUE951]

4 minutes ago, docholliday666 said:

 Plus, the hundreds of plugs I've changed out in the last 4 years says otherwise.

You've changed out 'hundreds' of plugs in the last four year.  Oh my gosh...   You do that for a living  

[docholliday666]

1 minute ago, WRUE951 said:

You've changed out 'hundreds' of plugs in the last four year.  Oh my gosh...   You do that for a living  

Not for a living, but I usually do my own work instead of sending computers, test gear, etc out for service. Can't trust these companies to do anything right and I also don't want to wait weeks to get something back.