External GPS antenna nRF9160 DK v0.8.2

[WassimZ98]

Hello everyone.

I know from Errata document that the GPS antenna soldered on DK is not working properly on the 0.8.2 version of the DK. I need to use GPS for time syncronization using PPS signal. I don't have a mxhs83qe3000 connector for conecting an external GPS antenna. 

Here is the schematic of the gps connection to Nordic module:

I do have an I-PEX connector and an SMA connector for GPS too.

Can i solder directly an I-PEX or SMA connector to J6 and disconnecting the on-board A2 antenna by desoldering R5?

Do you have any suggestion for achieving this?

Thanks in advance.

[ketiljo]

That may not be that easy. The external antenna most likely have a LNA that needs power. This is supplied in the coax cable via a bias tee. Also, the LNA on the DK ideally needs to be bypassed. You should be able to feed power to an external antenna if you connect a 68 nH inductor between SB1 and J6. Cut the track between J6 and L3 and place a 39 pF cap. The idea to replicate the schematic from a newer DK: https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/gps.html#gps

L10 and C26

You can replace J6 with a more suitable connector.

[WassimZ98]

Thank you very much for the answer. And what about J1 connector for LTE antenna? I need to attenuate the coverage in order to assess the power consumption, so I need to connect an attenuator to the DK. How can i do this without SWF connector? Thanks

[ketiljo]

That's more difficult. It's probably easier to get the test cable: 

https://www.digikey.com/products/en?keywords=MXHS83QE3000

[WassimZ98]

Ahh ok. Or, is it a way to reduce the on-board antenna coverage, maybe putting some objects on it? Do you have any suggestion?

The problem of the test cable is that it may take long time to arrive

[ketiljo]

Wrap the antenna in aluminium foil?