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PL-259 to BNC-F adapters on eBay

I prefer BNC connectors for their: size, weight reduction, quick-connect, etc.
I bought a few of these adapters from China on eBay and they were quite good.

I bought a few more from a different vendor and when the new batch arrived, 2 of them had self-disassembled in transit. The guts are press-fit, no crimp. I found that when they get cold, as in sitting outside in the (cold) mailbox on in your ruck during a winter activation, the white plastic insulators contract more than the outside metal shell and they literally fall apart (easy to loose the small parts).

They can easily be reassembled when cold and when warmed back to room temperature, they seem solid enough. They also press fit together easily at room temperature.
This is easy to test in the freezer at home. Put them in a zip lock bag or container so the parts don’t separate and scatter.
Yes, I did cold-test all the other adapters that I have and might use on a summit (including the spares),

Clearly, I won’t be using these dodgy adapters in the field for anything and I will mark them with bright nailpolish. Or maybe just recycle them.
The eBay vendor did offer a refund.

I wonder what other kit I have which doesn’t behave well in the cold?

  1. Batteries are obvious so I try to keep them warm and wrap them in a layer of insulation in the winter.
  2. Fingers too, which enhances my QLF. :wink:

Any other thoughts?

I dislike these adapters in general although I do have plenty of them. For something that will be fitted once and the cables wont be moving then they’re OK. For use in the field, I’d much rather have a short piece of coax with the right connectors fitted. In this case a PL259 to a coax cable socket and say 30cms of coax between the two. There’s much less strain that way on connectors on the radio. Whenever I see people using SMA to BNC adapters on the top of a small handy I have to look away. I’ve seen BNCs on a handy fail several times from leverage forces so you can imagine how much more vulnerable an SMA will be.

I have long given up with cheap chinese connectors or adaptors as have these can result in poor performance or fall to pieces as the worst possible moment.

Rather would get Amphenol, Pulse or other quality brands, once bought usually last forever and are well worth the extra expense in the long run.

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When I do that - as I often do, I run the coax (RG58) through the belt clip on the back of the handie, before looping it over and then connecting the BNC. That takes most of the strain off the adapter and BNC plug.

Worse is when some long 2m rubber duck that has a BNC is fitted to the adapter and then to the SMA. Ow!

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We were lucky when we got the VX-7s to find “Low Profile” SMA/BNC adaptors which screw down hard onto the top of the radio with a hard rubber washer. They have supported a 300mm stick aerial for several years through a good deal of careless handling and several hundred activations. I have had to resolder the socket only once during this time. Much touching of wood and finger crossing after writing this :wink:

73,
Rod
Edits
Of course, the main reason for using these and not the SMA connector is for quick fitting of the water-pipe dipole.
I have several 259 joiners fall apart too.

Andy,
You’d like this one then…

Seen at Dayton, 2010.

Andrew VK1DA/VK2UH

3 Likes

Want more power to Antenna ?PL259, BNC connectors el cheapo dielectrics are made of plastic and when measured have a 0.25db loss where as the slightly more expensive teflon dielectric have around 0.1db loss (Ampenol or Summer). Running QRP and running cheap coax over 10m plus several of these el cheapo connectors one could end up with a 3db loss. i.e. if running 10W then only 5W gets to antenna. less connectors good quality coax and more power radiated.
Had devil of a time with cheap BNC intermittently disconnecting and found that the concentric ring inside had no slits on circumference. This ring expands on inserting to make good shield contact. hmmmm i only got what i paid for + hours of frustration wondering why no contacts and high VSWR :slight_smile:
Cheers from down under
VK5TBC 73s

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Amphenol, Suhner, Radiall and Greenpar for me whenever possible.