About a year time I got from eBay 10 male BNC connectors, so me to roll two new patch cables, and also to have few as spare.
Out of the box they looked as normal BNC connectors of medium quality, which this is what you usually find almost anywhere.
In the begging at first 10 matting's their behavior looked as normal, but them I started to have serious connectivity problems.
After in depth inspection, I did notice that their center pin this started getting discolored, and also that the round barrel that this supposed that makes contact with the inner barrel of one female BNC, this was so small in diameter that it was not touching anywhere ...
By taking apart one of those BNC with my cutting pliers, I did realize that my money were wasted by getting garbage instead of connectors.
Plain painted iron everywhere and nothing can fool a magnet.
My next step was making some research so to find one branded source of BNC connectors so to get what I need and actually high quality 50 Ohm (RG58) connectors, so them to survive for some years.
My new find was that very few vendors have BNC male connectors which their inner ground barrel does 100% good matting with the female BNC, the devil is hidden in a small mechanical detail.
Please see my first attached image.
By searching now the market with my fresh eyes, I did realize that only Pomona and Amphenol RF, them use almost as standard this design which warranties perfect connection even if the BNC connector this is not locked by half turn.
There is no need to say that after inspecting about 20 BNC connectors which I did buy over the years, no one qualify as perfect connector.
Most of them are anonymous ( Possibly made in Taiwan by ULTIMAX an 2002 production), them following an generic BNC plug design and them using real copper.
It seems that in my second youth I learned a good lesson, and from now and on I will buying exclusively Amphenol RF connectors, there is availability in Greece and their price it is not that hostile ( 2.20 EUR per BNC plug).