Simple wireless mod

[Guest]

[Picasso]

A user in Japan has posted some pictures of a very simple mod to get a little better wifi. You can use google or the fish to translate it. http://k1.blogs.com/weblog/2005/04/what_is_this.html It's just a wire cut to the correct size for 2.4ghz A very simple and cheap mod to try. I my self have not tryed this as I use the correct ms-151 part to connect to an external antenna.

[telemarker]

As soon as I read this suggestion, I went to the garage to cut a 3 cm length of wire... small solid guage, maybe about 28 or 30 guage, so that it fits inside the external antenna connector.  The rationale for 3 cm is that the speed of light is 3e8, divided by 2.4 GHz, results in a full wavelength of 0.125m, for which 1/4 wavelength is 3.125 cm.

Back in my kitchen, monitoring netstumbler showed a dramatic 10-20 dB improvement in signal strength.  Without the wire stub, in the same location, the OQO bordered on being unusable for web browsing.  With the wire stub, it's a solid "Good" signal strength.

Wow, thanks to kei_1. 

As an aside, the OQO's external antenna connector is made so that when a normal plug is inserted, the internal antenna is physically disconnected (in the same way that plugging in headphones disables speaker output on amplifiers).  This idea does not accomplish that, so there is probably a suboptimal impedance match to the now dual antennas.  But who will complain, with this kind of performance gain!

[garylm]

kei_1:

Scheme for Fixing the Deficient Sensitivity of the OQO Wireless LAN

What is this you may ask?  A white wire in the OQO's external wireless LAN antenna receptacle...

As a matter of fact, it is an antenna.  Ok, well, it's simply electrical wire, cut to approximately 2.5cm, with the pointed end stripped of insulation and inserted in the receptacle to see what would happen.  And the results!  The sensitivity of the wireless LAN is much improved.  As far as signal strength, it was very strong at the location where I tried it.  The result seems to be that even this simple antenna is better than the internal antenna. (I wonder about the design of OQO's antenna.)

Anyway, I'll give this one a try for awhile.

I haven't yet tried the antenna that I received and wrote about yesterday.  Perhaps later when I have a chance..

ka10:

Talk about the scales falling from my eyes.  My thoughts about the antenna were focused on lambdas, and 1/4-wavelengths, and theorems requiring difficult calculations.  One site was talking pessimistically about needing a big conversion with a special connector sticking out...

I too will give this a try.

kei_1

Good morning ka10-san

Yes, please give this a try.

After considering the length of commercially available wireless LAN antennas, I found that just cutting and trying proved quite adequate.  I think the results are the most important thing.  I think it would be good if everybody could try this with various lengths.

kei_1

A 2.4 GHz wave has a wavelength of 12cm.  Therefore, 1/4λ should resonate at about 3 cm.

I am trying again with a 3cm tail that I made.  I posted this using my new tail.  It looks like it's good.

Don't count the part of the tail that is jammed in the connector as part of your 3cm (the connector is shielded).  Also, if you use the proper gauge of antenna wire, it should engage the internal antenna disconnect mechanism inside the connector.

[3vw]

So I thought I'd give this a try with just a piece of spare wire I had laying around. All I can say is WOW! I didn't expect it to improve as much as it did. My AP is in the library through a wall and I'm getting an "excellent" signal now where I was only getting "good" - "very good" before.

What a wonderful simple mod... I wish everything was this EZ to fix.

Many thank Picasso for sharing this and thanks Garylm for translating the original page. BTW is the internal disconnect for the Wifi a mechanical action or is it like an electrical bridge that needs to be made? 

[garylm]

3vw,

I think it was Picasso who posted on Handtops.com some manufacturer's links for the connector.  I remember following one of those links and finding a cross-sectional diagram of the connector, showing the internal disconnect.

Knowing that sticking a wire in the hole is going to disconnect the internal antennas, I would be careful when selecting wire for the antenna.  Copper may be too soft.  I would hate to have it break off in the connector and leave me with no antenna.

I haven't tried the antenna trick yet, but I have in mind to try a steel bristle from a wire brush that I have at home.  Those bristles are tough, and they're about 3cm long.

[garylm]

The brush bristle works well.  With the entire length of the wire exposed, I can slide the wire in and out to find the strongest signal.  I'm afraid the wire might go in too far, as there is no detent position.  The intended depth of connector penetration can probably be determined from the connector manufacturer's drawings.  The sharp, bare wire will need a bead of glue or silicone along its length, and maybe a sleeve of tubing to protect the insertion end.  The brush bristle is a lot tougher than solid copper wire would have been.

[Picasso]

You can find the doc here for the connector. http://www.hirose.co.jp/cataloge_hp/e35801587.pdf

[3vw]

Garylm,

Thanks for the advice but I would encourage you or anyone else trying this mod to actually stay with using a soft bendable wire (like copper) as opposed to something rigid (like steel). My reasoning is that it can bend when you happen to bump it (and you will) and in turn it will not damage the jack (receptacle) as something stiff could/would do. I’m not afraid of the copper wire breaking off unless the end was nicked (scored) while striping the insulation off. Just be careful not to do this and you should be fine. Hey, if you bend it too many times just make a new one… they’re cheap to replace right. lol

Here’s my little pig tail and it works greeeat!



If you can make it out there are 5 bars showing on my signal strength now. woopeee


FYI I found that a 24 gauge solid core copper wire (measures about .020” in diameter) fits just right. (not to tight or loose). I put a little heat shrink handle on the end that gives it an oqo-puncture look. hehe

[garylm]

The drawings show the mating section of the MS-151 plug at 5.5mm in length, with the center pin a bit shorter...approximately 5mm.  However, the drawing of the two connectors coupled shows the plug contacting the shoulder of the receptacle before the center pin is fully inserted.  Just eyeballing the drawing suggests that the center pin is inserted to a depth of about 3mm.

[IZodiac]

wow i saw the same thing on flickr when i search keyword "OQO"

here: http://flickr.com/photos/kei_1/8195510/

[garylm]

Kei_1 responds in his blog to Picasso's link:

OQO Talkで議長をされているPicassoさんからこのエントリーにコメントをいただいて、OQO Talkを見に行ったら、私のしっぽアンテナのアイデアが話題になっていました。
これはうれしいですねえ。

こちらのスレッドです。

実際に試してみた方から効果があったことが報告されており、私もとてもうれしくなりました。

まだ試されていないOQOユーザの方で、無線LANの感度不足に悩んでいる方はぜひ試してみてください。かなりの改善が見られるはずです。今日も東京メトロのいくつかの駅で試していたけど、しっぽアンテナがないと接続できなかったところで、しっかり無線LANが使えましたよ。

I received a comment in an entry from Mr. Picasso, who heads OQO Talk.  If you go to OQO Talk, you will see that my "tail" antenna idea has become a topic.  This is something to be glad about, isn't it.

To have the results reported by someone who has actually tried it makes me really glad.

If you're an OQO user who hasn't yet tried this, and you've been troubled about the insufficient sensitivity of the wireless LAN, you should definitely try this.  You should see a considerable improvement.  Today I tried again at various Tokyo Metro rail stations, and at those where I hadn't been able to connect without the "tail" antenna, I was able to use the wireless LAN reliably.

*moves to Tokyo, where they have wireless LAN in the train stations*

[OQOemulator]

Hi guys, I did the wire mod and it seems it works fine. But I have a problem.
Now when I use my OQO without the wire it acts like I have no antennas at all because it always shows Low to Very Low.
Even when sitting right next to my Linksys Wireless G Router it shows Low. Before the wire Mod, it used to show Excellent at all times when I would be next to the router.
Did I do some kind of damage to the OQO or is there a way to disable the antenna port where small wire mod goes? If you could shed some light on this it would be great. Thanks.

[garylm]

@ OQOEmulator:

Perhaps a piece of your wire broke off in the antenna socket, leaving the contact inside the connector disengaged.

[OQOemulator]

@ OQOEmulator:

Perhaps a piece of your wire broke off in the antenna socket, leaving the contact inside the connector disengaged.

  I doubt that since I used a decent gauge wire and it does not apper to be broken or shorter from tip that goes in.
I'm wondering if there is another way to engage it again so that my regular oqo antenna works.   

I shoulda never touched this thing. 

By the way Picasso, since you opened your OQO, is there a CMOS Battery inside? Maybe if I take out the battey for a minute, the whole board will reset itself? 

[garylm]

I used a decent gauge wire

Hopefully the wire wasn't too fat.

Enough people have tried sticking a wire in the external WiFi antenna port that it seemed like a fairly safe procedure.

Here's a schematic of the insides of that connector:


You can see from the schematic that the connection between points A and C is broken when a wire is inserted.  The A-to-C contact should be restored when the wire is removed.  Perhaps C is now permanently bent away from A, maybe because your wire was too big or because the wire wiggled from side to side inside the socket or because you jammed your wire in too far and bent contact A.  Or perhaps the contact between A and C is dirty (there might be some lint in there).  Maybe there is something you can do to clean that contact.  I might try a very fine and very strong steel bristle from a wire brush, fishing the bristle in and out of the hole a few times.