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Due to space constraints on a board I am designing, it is ideal to have the GNSS cable connecting vertically onto the top of the board. I haven't been able to find any edge-mounted connectors that go to a right angle vertically. Obviously edge-mount would be ideal electrically, but I am wondering if it will introduce too much loss too use a through hole SMA connector mounted vertically on top of the board - the 50ohm trace leading to the GNSS receiver would a top mounted grounded CPW line (signal trace on top with ground planes surrounding trace on top, and ground plane below the signal on the bottom side of board). I am concerned about 1. since it is TH, it will be soldered on the bottom, so there is a possibility of shorting the signal pin to the grounded housing of the connector; or possibly not getting a good enough connection to the top-side of the plated through-hole - where the trace is connected. 2. Loss due to the right angle bend where the signal pin meets the plated through-hole. 3. The leftover stub of signal pin sticking out of the bottom.

Here is the digikey link to a possible connector: https://www.digikey.com/product-detail/en/cinch-connectivity-solutions-johnson/142-0701-201/J500-ND/35274

This for GNSS applications, so it is all below 2GHz.

Thanks for the help!

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  • \$\begingroup\$ Since it's a cable: what about U.FL connectors? They are surface mounted, tiny compared to SMA and there's lots of SMA to U.FL cables or even antennas with a U.FL pigtail \$\endgroup\$ – Jan Dorniak Sep 27 '18 at 23:14
  • \$\begingroup\$ Passive or active antenna? \$\endgroup\$ – pericynthion Jul 16 at 15:27
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I haven't been able to find any edge-mounted connectors that go to a right angle vertically.

If this is a one-off hobby project, you can probably use one that looks like this:

enter image description here

Typically a 0.062" thick PCB will just fit between the center pin and one pair of ground stakes, allowing you to use this as a clunky edge-mount connector.

Or you can use a right angle adapter with whatever edge-mount connector you like.

since it is TH, it will be soldered on the bottom, so there is a possibility of shorting the signal pin to the grounded housing of the connector

We (EEs in general) solder through hole parts with 0.050" spacing all the time with no trouble. The spacing between the body legs and the center pin on an SMA connector is typically more than twice this distance (it's about 0.14" on your part).

Loss due to the right angle bend where the signal pin meets the plated through-hole.

At 2 GHz this will not be a big effect.

The leftover stub of signal pin sticking out of the bottom.

This is a real concern when using SMA connectors near their frequency limits (maybe 10 GHz and up). Ideally, you'd mount the SMA connector on the opposite side of the board from where the trace is to eliminate the stub.

At 2 GHz, it's not likely to be a problem even if you have the connector on the same side as the trace.

If you're paranoid, you can get connectors with through hole ground stakes for mechanical stability, but surface-mounted center conductor like this:

enter image description here

But these connectors probably need to be reflow soldered rather than hand-soldered.

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  • \$\begingroup\$ Thanks for the answer. As far as shorting, I was more concerned about shorting the signal pin to the underside of the connector housing, which shows a 0.02" spacing in the drawing. Although it looks like there's at least 0.05" spacing between the pin and the housing surrounding it. \$\endgroup\$ – Andy M Sep 27 '18 at 16:45
  • \$\begingroup\$ @AndyM, it's not worth worrying about. We also can solder 0402 passive component with less than 0.02" between the pads, and they don't bridge unless you are very sloppy. Solder likes to cling to copper, it doesn't like to jump across gaps to find more copper. \$\endgroup\$ – The Photon Sep 27 '18 at 16:48
  • \$\begingroup\$ If you're concerned about shorting, you could also run the signal trace on the opposite side of the board from where the connector mounts. \$\endgroup\$ – CrossRoads Jul 16 at 19:53
  • \$\begingroup\$ @CrossRoads, in that case you may as well just use the through-hole connector. \$\endgroup\$ – The Photon Jul 16 at 20:15
  • \$\begingroup\$ That would be more secure. \$\endgroup\$ – CrossRoads Jul 17 at 12:34

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