LDS01 with external Antenna

Hello,

i just received some Dragino LDS01 and i am pretty amazed of its simple Design and amazing pricing.
In some situation the internal antenna does not work well.
As there is an ipex connector on the topside of the board i asked myself if it can be used to easyly add an external antenna.
Does it require further modification or is it plug and play?

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I think you need to disconnect the internal antenna because 2 antennas at the same time connected to one transmitter does not work well.
As I have no circuit drawing I do not know if it is possible le or how to do that.

Thank you for your answer.
“How to disconnect the internal antenna?” is perhaps my real question.

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  1. Check the manual… nope, nothing there

  2. Ask Dragino

  3. Post a high resolution picture of the circuit board showing the connector and internal antenna

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I’m quite interested in this as well! Anyone with experience willing to help?

Picture of LDS-01 circuit board incoming

20201224_140924 20201224_141012

You could try desoldering the existing antenna and using the existing (and parallel wired) u.Fl connector to connect an external one. Make a note of SNR and RSSI as reported before the change and afterwards and don’t forget to report back because we’re curious of course.

Thanks for directions! Very little radio experience here but unable to get signal to/from a DS01 550m from gateway so now troubleshooting.

Parts to map and add antennas to both sides in the mail, so hope to be able to do in next weeks.

Regarding the embedded antenna - is there any community experience with this component? or are we better-off focusing on other factors? Also interested in any threads on adding antennas like this. 20201225_140902

What exactly should be desoldered?

The antenne on the back-side off the pcb

Thanks for the good picture. Now I know how the Dragino LDS01 looks inside without opening it. To explain a little bit what you are seeing there around the antenna: C1 is a decoupling capacitor to block DC-components, C3-L6-C5 form a low-pass filter to suppress unwanted (higher) frequencies.
The antenna is connected to the point where C5 and L6 meet. This point should also be connected to the inner conductor of IPEX1. It is hard to see on the picture whether there is a connection or not. Just measure the resistance between the connection of the build-in antenna and the inner conductor of IPEX1. It should be abt. 0 Ohms.
You can buy ready-made adapter cables from IPEX to SMA. I would not try to build them myself.
Remark: You have to remove the internal antenna before you use the IPEX connector.

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Thanks!

I purchased some IPEX-SMA adapter cables (http://bit.ly/2Ys1W9i), and got a very significant improvement with the RAK 7200 moving to an external dipole (http://bit.ly/2YnrK6t), so I know the antenna upgrade can work. However, while I was able to remove the LDS-01 antenna, I was unable to connect the LDS IPEX connector to the antenna cable IPEX slot.

I assume it has something to do with the type of IPEX connector, but haven’t been able to find where the issue is. Any suggestions?

imho the antenna you purchased is a 1/4Lambda (monopol) and not a 1/2 Lambda (dipole) antenna. A 1/2 Lambda dipole should be abt. 0.15m long.
I don’t know why there is a problem with the IPEX-connector. I use some of these adapter-cables also for GNSS without any problems.

I added an antenna to my LDS01 u need a IPEX MHF4 connector. Its smaller than standard IPEX U.FL.

if you google “U.FL IPEX MHF4 auf RP-SMA 0,81 mm RF Pigtail” you will find some.

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There is no resistor to remove, however you will need to remove the internal antenna as the externally connected one would be connected in parallel to the existing antenna.
BTW, make sure to use an RP SMA antenna if you are using the suggested pigtails, otherwise no center pin connection will exists resulting in no antenna connection.

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My mistake, just removed the antenna and attached an appropriate external, and it works!

Thanks for the advice @kersing !!

Final report: I desoldered the internal antenna and attached the IPEX1 MHF4 connector - not the IPEX4, a slightly smaller diameter is necessary, different than Rak wireless - and it works great!

I am trying to get a signal on the other side of a forest for cottage security, and while the original was not providing a single return, I am consistently getting medium-strength ones on even a fairly small antenna upgrade!! I have 2 units and testing them side-by-side shows clear result. This was just a couple dollars (USD equiv) and minutes to desolder the antenna, so I’m quite satisfied!

The final step is to run a cable from the door (beneath a steel roof) to a pole to maximize link budget.

Thanks to all who provided input. Hopefully this saves someone else time avoiding wrong components.

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20210329_170836 (1)

Thank you for sharing your experience!

Your result remember me to continue my work for a custom enclosure.
I have made good experiences with new firmware (>1.2) and the AT+MOD=3 command.
With a 3D printed enclosure it is a small and cheap but reliable device with two simple reed switches.

can you elaborate what you mean by AT+MOD=3? It sounds like you are using the hardware for something other than open/close?