[Swede]

Hello!

I opened my C71 today just to see how it was put together and I discovered that it has no antenna, just CC&C:s ML-294 Wifi USB dongle directly soldered to the motherboard. I think the wifi reception is pretty bad, Im sitting appr 4 meters from my router and have -60 dB in Wifi Analyzer. Does anybody know which of the connectors are shield and whic are core? I believe the tre soldering dots in the higher left on the board should be connectors for an external antenna. Is there any way of measuring to determine which one or the other? Sorry for the bad pics, I only have a bad mobile camera..:-(

Thanks

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[path0s]

Actually, there IS an antenna on that board, it's called a "chip antenna". It's the rectangle thing in the lower left of that picture underneath where you thought they were. I'm not sure what those other pads are for, they don't look like the pad pattern for a mini rf connector. I tried to look around for a datasheet on the WM-294 module here, but only thing I could find on their website is: marketing@ccandc.com.tw under support.

Here's a page where someone did the same thing as you, but it's in spanish. At least you can sort of make out the pictures.
http://foro.tiendach...-wifi-zt280-c71

I don't want to hijack your thread too bad but do you know if it's possible to remove the installed wifi adapter and replace it with one that has wifi/bt/gps all in one unit?

[pyotr]

In opening the C71's back I managed to cause the WM-294 module to separate! The six tabs which were probably originally part of the main board stayed with the WM-294 which came away from the board completely. With only elementary soldering skills, do I have any hope of re-attaching the WM-294? Can i attempt to solder the six tabs back to where they came from on the main board? or is it likely I have I gone down into the substrate below the layer where the metal strip is?

[jsaily]

The connector pads on the WM-294 are meant for a U.FL type connector, which is pretty standard for 2.4 GHz WLAN antennas in laptops etc. If you wish to modify the WM-294 module to have a better antenna, you should desolder the ceramic chip antenna (white chip with a red dot) and solder in a U.FL connector on the pads near the chip antenna. Then you can use a standard laptop wifi antenna with U.FL connectorized cable.

I'm probably going to modify my C91 sometime with a better antenna although it already has an external antenna.

[R. Olinger]

I did try to hack in an antenna based on a different post, and I soldered the core and shield directly to the pads on the top left (in your picture) which are not where the chip antenna is placed. Needless to say, I had bad information and the mod did not really make any difference. I'm hesitant to remove the chip antenna and try re-soldering, but I may. It is kind of a one-way trip, if you screw it up, the pad is pretty much useless.

Randy
C71 ZT-280 Gingerbread (for now...)

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[Jacopo]

R. Olinger, on 08 January 2012 - 12:37 PM, said:

I did try to hack in an antenna based on a different post, and I soldered the core and shield directly to the pads on the top left (in your picture) which are not where the chip antenna is placed. Needless to say, I had bad information and the mod did not really make any difference. I'm hesitant to remove the chip antenna and try re-soldering, but I may. It is kind of a one-way trip, if you screw it up, the pad is pretty much useless.

Randy
C71 ZT-280 Gingerbread (for now...)

You have to remove the ceramic antenna and solder the new one this way:

This post has been edited by Jacopo: 08 January 2012 - 06:40 PM

[Swede]

Thank you very much for all the answers..:-) Jacopo, did you get better reception with the new antenna?
To summon the process upp, I have to desolder the rectangular thingy in the lower left corner in my picture and then solder on the new external connectors on the remaning contacts, is that correct?

[brew99]

Jacopo, How long of antenna wire are you using, and is the shielded braid up the entire length of the antenna wire? Seems to me that the braid would need to be stripped back a bit (3 or 4 cm) to not shield the centre conductor wire (radiating wire). Does this infact improve signal strength, cause the stock is the @##$$$.

[Jacopo]

Swede, on 11 January 2012 - 10:30 AM, said:

Thank you very much for all the answers..:-) Jacopo, did you get better reception with the new antenna?
To summon the process upp, I have to desolder the rectangular thingy in the lower left corner in my picture and then solder on the new external connectors on the remaning contacts, is that correct?

I've changed the standard ceramic antenna with a laptop one and I get better signal, it almost doubled and now it's higher than my BlackBerry 9780.
Yes, you have to remove the white "rectangular rhingy" in the lower left corner and cleans pads with desoldering braid if you have it, then solder the new one with central wire on top and shield on bottom.

[Maxximo88]

Jacopo, on 14 January 2012 - 09:27 AM, said:

I've changed the standard ceramic antenna with a laptop one and I get better signal, it almost doubled and now it's higher than my BlackBerry 9780.
Yes, you have to remove the white "rectangular rhingy" in the lower left corner and cleans pads with desoldering braid if you have it, then solder the new one with central wire on top and shield on bottom.

Jacopo I hope you make a good step by step guide on how to replace the original antenna with an notebook antenna (or compatible) as soon as possible!

[Jacopo]

Maxximo88, on 21 January 2012 - 05:18 AM, said:

Jacopo I hope you make a good step by step guide on how to replace the original antenna with an notebook antenna (or compatible) as soon as possible!

Last week milu has pubblished a good step by step guide.
http://www.slatedroi...reless-antenna/

[Cracker_Jack]

Jacopo, on 21 January 2012 - 05:57 AM, said:

Last week milu has pubblished a good step by step guide.
http://www.slatedroi...reless-antenna/

Just a standard laptop antenna, (one black & one white wire)? Which wire solders onto which pad?

This post has been edited by Cracker_Jack: 25 January 2012 - 12:59 PM

[jsaily]

Cracker_Jack, on 22 January 2012 - 10:56 PM, said:

Just a standard laptop antenna, (one black & one white wire)? Which wire solders onto which pad?

Assuming black is ground then you should solder the white wire to the line coming from the matching circuitry, and black wire to the side ground pad.

[Jacopo]

Cracker_Jack, on 22 January 2012 - 10:56 PM, said:

Just a standard laptop antenna, (one black & one white wire)? Which wire solders onto which pad?

Usually laptops have two antennas, you will find a white coaxial wire for the main one and a black coaxial wire for the auxiliary. You have to use only one antenna, for how to solder cable looks at the picture a few posts above.

[Cracker_Jack]

Jacopo, on 27 January 2012 - 06:11 PM, said:

Usually laptops have two antennas, you will find a white coaxial wire for the main one and a black coaxial wire for the auxiliary. You have to use only one antenna, for how to solder cable looks at the picture a few posts above.

Thanks for the clarification, you are right, after looking closer at the old laptop antenna cables I realized it is infact two very small coax cables. This is where I was confused assuming it was two single wires with no shield casing.

[Brickbeats]

How about soldiering in a wifi/Bluetooth usb module?

C71

[Jacopo]

Brickbeats, on 04 February 2012 - 08:39 PM, said:

How about soldiering in a wifi/Bluetooth usb module?

C71

It could be done but your card need to be supported in kernel or you need to load a kernel module.

[hhp_211]

Thank you for another good wi-fi antenna write up

[Cracker_Jack]

Crap, I pulled the trace off in the picture by accident, I think its a ground pad but can anyone please tell me in the picture where else that pad is connected so I can solder elsewhere???

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This post has been edited by Cracker_Jack: 14 May 2012 - 10:42 AM

[Cracker_Jack]

Anyone? a couple seconds with a continuity tester to find this out for me would be greatly appreciated.