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I'm looking to attach 50 ohms coaxial cable to a circuit board. The signal is only 1kHz. The thought I had is below. Have a pad to solder the braid. Have some space between the braid and center electrode of some insulation and then the center electrode. Maybe for kicks have some drills to run a zip tie through for strain relief. Possibly via stitch the braid pad to the GND layer underneath for added strength.

Are pads like this standardized or am I on my own for this?

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Why would you not use a standard connector like a BNC? \$\endgroup\$
    – Ron Beyer
    Dec 27 '20 at 2:50
  • \$\begingroup\$ I don't know if there is a standard but it should work fine. I have seen it done before even at UHF on cost sensitive products. There are also edge mount sma and smb connectors that are pretty small and might also work if you want to terminate the cable. \$\endgroup\$
    – mkeith
    Dec 27 '20 at 4:25
  • \$\begingroup\$ sunrom.com/media/content/1588/bridge_edge.jpg \$\endgroup\$
    – mkeith
    Dec 27 '20 at 4:26
  • \$\begingroup\$ @RonBeyer I have to pass the cable through the side into a small enclosure. BNC anything would kill my space budget. \$\endgroup\$
    – vini_i
    Dec 27 '20 at 13:51
  • \$\begingroup\$ If you're desperate for space, you could cut a notch the width of the coax into the PCB so that the centre conductor is level with the surface of the board. \$\endgroup\$ Dec 27 '20 at 16:58
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Yes it has standardize connection to PCB, but it's more like common cable connector attached to PCB. It's been used by decade of some old manufacture usually in Asia. You wouldn't see in US i guess because it's not common procedure.

See this image the bottom is the connector for coaxial cable

It's mainly use in TV booster on Asia.

And again this is not the best procedure at all not even meets the new standard, but you can try if didn't want any BNC connector to eat your space project..

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I'd do the center conductor through-hole and for the braid put hoop of wire over it and solder it to the braid and put the ends of the hoop through holes too.

I think that's how I did my home built TV antenna amplifier on strip-board.

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The standard solution is to use a connector. If you want to solder directly to the PCB then signal integrity won’t be a problem at 1kHz, but mechanically it’s a poor solution

  • it’s difficult to disconnect
  • there’s a danger of ripping the pads off the PCB
  • it’s not pretty Bigger pads will adhere better. Perhaps consider a couple of cable ties so you can keep the coax aligned as well as strapped down.
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I would use a connector (if BNC is too big, go for SMA or U.FL or some other tiny connector), but if you absolutely must have no connector on the cable side, there are direct-to-cable connectors, such as this one, that you just press a coaxial cable into and crimp in place, and even more easily (and more reversibly) IDC ones like this.

Still, you would be surprised how small some connectors are. This type is only 5 mm in diameter, which is thinner than some coaxial cables!

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