How can I reconnect loose antenna cable

Any repair-cafe around there?

Did you try soldering the cable by yourself?
The reason I ask is that antenna connectors shouldn´t be soldered related to the attenuation.
I guess you are German, so here is some footage about how an antenna works:
http://www.elektronik-kompendium.de/sites/kom/0810171.htm

@ElKrasso: Thanks for the hint about the soldering. Luckily, I neither did nor considered it :slight_smile:

But if I interpret this video correctly, those connectors are rather crimped than soldered anyways.

…correct

…also correct

But they speak of “cold solder joints” which are a sign of improper soldering. Usually such antenna connections are crimped, but at some point they start with a solder joint (on the PCB the socket is soldered onto not crimped into the board as I assume).
And a completely torn apart cable will surely result in an attenuation of 100%.
So if there is no proper replacement cable, soldering can help a bit.

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but will have an effect on the reception, I guess.

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@Patrick1: Thanks for the clarifications. Now I get all the remarks about soldering.

From what it looks like, the socket really is soldered to the PCB. The connection however looks solid and undamaged. The connector can also still be attached to the socket by simply plugging it on and off. My issue is rather with the connection between the cable and the connector. So I guess I am stuck with two options.

  1. Get a used FP2 antenna cable from Fairphone support or a member of the community.
  2. Find a workshop or repair café that have a crimp tool and an MHF3 connector to repair my current cable.

Anyway, thanks for the support, guys. If anything works, I’ll make sure to post it.

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My phone is working again, yeah!

For the record, I went with both options in parallel.

@Freubert was so kind to send me a spare antenna cable of his phone.

While on the way, I also went to a repair shop to see, whether they could fix my original cable. They could not. However, they gave me a simple RF cable with MHF3-connectors. Interesing enough, this cable works, although it lacks the PBC attached to the original Fairphone antenna cable. Does anybody know, what this board is supposed to do? Apart from this suspicion, I could not find any information about it. The antenna seems to work perfectly fine without it, though.

Original fairphone cable with mysterious board in red frame. The antenna board on the right can be easly plugged off and on again.

Cable I got from the repair shop (similar) without mysterious board.

Cable

I’d love to learn, what the heck this PCB does. Is there a captain here?

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Interesting.
Did they customize it to the required length themselves, or is this a ready-made part of some sort?
What was the price you paid for it?

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It was about a centimeter too long. But I just curled the excess length of the cable under the antenna board.

He offered it for free. But after seeing that it solved my problem I gave him 10 €.

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It seems to be the antenna for Wifi reception.

Here some Wifi antennas with a type of MHF connector can be found.
As many antennas does not only need the signal line but also a connection to ground this small pcb seem to do nothing else than hold the two wire ends and provide contacting pins for grounding to the back of the display.

The thing with antennas is, they have to be matched with the signal which they want to receive/transmit/transceive etc.
So the signal has a specific wave length according to the frequency band (2,4GHz/5GHz) here. To have the best reception the antenna needs to have a specific size/length. Too short may not work properly, too long as well.

Specialists are talking about things here like Lambda/Lambda 1/4; Lambda 1/2 etc. Huge technical playground for those enthusiasts.

So in your case there may also be some luck involved. Good for you.
Thanks for your feedback.

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Three months on, I’d be grateful to hear if your FP2 still works with the alternative antenna cable, @MatthiasBremen ? I’ve had people giving up on their FP2 recently just because there was an issue with the antenna, so I’m pondering whether to write a pre-emptive note encouraging others not to give up early should they be affected in the future.

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Hi Urs,

that is a cool Idea. My Fairphone 2 is still working perfectly fine with the replacement antenna, although there is no PCB on it compared to the original antenna cable.

Best,
Matthias

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No post in a long time, but just want to ad for anyone else having antenna problems, I want to share a link to a potentially useful cable (if you are in the UK), thanks to @Patrick1 for clarifying the type of connector. The cable pictured looks like a Female U.FL to Female U.FL (also known as a I-PEX MHF) . I am guessing the part number might be U.FL-2LP(V)-04N1-A-(35) though I think the length may be too long at 35 mm. Also just guessing here but it looks like there are two of these, attached to the center board. Either way I will give it a go and update you here.

Here’s a link to the cables I have purchased: https://uk.rs-online.com/web/p/coaxial-cable/1360902/

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Hi ardo,
similar issues here. Did you find a suitable antenna? The one with 35mm seems to short (mine is between 80-85 mm - the one on the side).

Maybe this one could work (100mm): https://uk.rs-online.com/web/p/coaxial-cable/1360912/

You’re right; I thought there were two cables connected on either side of the rectangular board in the middle.
Also , It turns out that it is not a u.fl connector but it’s miniature cousin the w.fl.

Could try the 100mm cable as has been mentioned above but I don’t understand how it would work, because the length of the cable usually determines the frequencies that get picked up, unless that mysterious board in the middle has some kind of filtering function.

The only distributor that seems to sell the 80mm w.fl cables has a minimum order number of 100!
I’m going to call on @Fairphone to check if they have any spare.

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Hi ar.do,
did you succeed with @Fairphone or did you buy 100 antennas?

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Hi @UFL, thanks for asking! I managed to get three W.FL 100mm cables, I don’t remember if I bought from RS components UK or Farnell. I’d say it is worth a trym I had two phones with the issue, one from a friend, and it solved the problem with one phone but not the other. It’s fairly doable if you have done any electronics before. Don’t forget to also get a Torx T5 screwdriver if you don’t already have one.

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Thanks for the update! I found one at Farnell (but only companies can order - for other readers):

note the different size of the connector-head (w.fl is the one needed)

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