SMA to RF out pin

Other Hardware General Electronics
1

Hello I would like to connect SMA antenna (433 mhz) to my Lora SX1278 radio also 433 mhz. But how do i plug the SMA connector to radio pins on radio moudl? Thank you in advance.
Mark

With the default antenna:

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With the SMA antenna:

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2

The center is the antenna the bass threads are GND.

3

Hello,
Thank you Larry, I think i get it now (see image below).
Marek

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4

I would buy an SMA extension lead of some sort, and cut off the other end.
Then strip and solder the coaxial wire (center and ground) to the radio.
Make sure the connections are short, not like the images on previous posts.
Leo..

2 Likes
5

I would not do it like that.

The pad next to the antenna connection on that LoRa module is very liklely a ground connection. So connect the ground of the SMA connector to that pin. Keep all wires as short as possible.

1 Like
6

You need to do it without using any wires at all. Mount the connector directly on the PCB in the manner indicated below:

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(You can only make 2 connections, and not 3 as in the example)

1 Like
7

I would take great care, if you attempt to solder a SMA Edge socket onto a board that does not have the pads for it.

A 434Mhz antenna on the SMA socket could exert a fair bit of leverage on the very small pads on the LoRa module, they could rip off.

You can of course buy SMA chassis sockets with a thin bit of co-ax already attached, they often have an IPX connector on the other end. Cut the IPX connector off and the co-ax is ideal for soldering onto the LoRa modules small pads. Low risk of damaging the LoRa module too.

8

I thought i could use this (image) coaxial wire and solder it in those 2 pins, because the SMA connector is way too big for those pins. But I have no idea which one is GND and which one is the active. Do you know?
Thanks,
Mark

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9

Centre wire is antenna, outer screen of co-ax is ground.

But easy to check with a multimeter .........

10

I meant the end of the wire on this picture, where it divides in two.
Thanks,
Mark

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11

The insulated wire connects to "ant"
The multiple braided/twisted wires connect to "gnd"
ant and gnd should be printed on the back of the module.
Leo..

12

Thank you sir

13

It is there :+1:
lora

15

Do you actually have one of those connectors ?

16

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