A Quick Fix of My Wi-Fi Connection Issue – Bad Wireless Channel Condition

No comments    yoichi

December 25th, 2011 

I was in a hotel where there was no wired internet access, I had Emobile Internet access which was only internet access at that time but I wanted more than one devices to be connected at the same time. I setup Internet Connection Sharing with my MacBook Pro in order to share emobile connection to the other devices via Wi-Fi. The setup procedure was perfect however it didn’t work somehow – my Wi-Fi connection dropped out repeatedly. After my more-than-an-hour investigation, I finally found the root cause of the issue. It was wireless signal interference – Wi-Fi channel number overlap between me and my neighbors in the hotel.

This below is how I setup Internet connection sharing with my MacBook and How I resolved the issue.

Sharing Emobile Connection to Computers Using Wi-Fi

Assuming that your Macbook is connected to the Internet using a Emobile modem.

1. Open System Preferences > Click Sharing

2. Select Internet Sharing (However don’t turn on Internet Sharing Yet, otherwise you won’t be able to edit Wi-Fi Option)

3. Choose “Share your connection from” and “To computers using” like this:

• Share your connection from: Emobile Modem (ex. HUAWEIMobile-Modem)
• To computers using: Wi-Fi

4. Click Wi-Fi Options and configure an internet-sharing network. Here is my configurations:

• Network Name: mbp-shared-wifi
• Channel: 11 (default)
• Security: 128-bit WEP

5. Turn on Internet Sharing

That is all need to be done for internet sharing. You should be able to join the shared network “mbp-shared-wifi” if the channel( more specifically one of 11 802.11 channels) that you chose is not interfered by any sources of signals near the network.

Finding Out The Right Wi-Fi Channel

The purpose here is to find out the right channel for the internet sharing, the one which is least occupied.

Airport Command included in Mac OS X

airport is a built-in command line tool that enables you to manage 802.11 interfaces and to get all sort of information for 802.11 interface.

First, the tool is not located at one of paths which are included in $PATH, so let’s create a symlink to the tool like this:

A command line “airport -s” performs a wireless broadcast scan and gives you a list of Wi-Fi networks nearby. It reports information about SSID, BSSID, RSSI, channel, authentication, and so on.

Now you want to know which channel is used least from the output of “airport -s”. This command line below gives you numbers of how many of access points(SSIDS) use each channel.

From the result above, it would be good to choose channel 8, 3, or 10. I chose channel 3 this case. I setup the internet sharing again with the channel 3, and confirmed that I was able to to join the shared network “mbp-shared-wifi”.

Also pay attention to RSSI

You may want to pay attention to RSSI. According to wikipedia, RSSI is the relative received signal strength in a wireless environment, in arbitrary units. RSSI is an indication of the power level being received by the antenna. Therefore, the higher the RSSI number (or less negative in some devices), the stronger the signal.

Simply, the channel with lower value of RSSI is less likely to cause interference than the one with higher value of RSSI. It would be good to choose the channel with least value of RSSI for the internet sharing.

Web Based Tool – Wifi Stumbler

There is a local wifi scanning web service, called “Wifi Stumbler“. This service provides you the information to choose the best wireless channel to choose. A good thing about this is that this is free web serivce, you don’t need airport command or any kind of wifi scanning software to install on your computer. See the site for more detail. Here is the scanned output of my wifi environment by Wifi Stumbler.

http://tools.meraki.com/stumbler

REFERENCES

• http://en.wikipedia.org/wiki/IEEE_802.11
• http://www.microsoft.com/athome/setup/wirelesstips.aspx
• http://wlanbook.com/mac-os-x-wifi-wireless-scanner/
• http://en.wikipedia.org/wiki/Received_signal_strength_indication
• http://tools.meraki.com/stumbler
• http://lifehacker.com/5538927/wifi-stumbler-scans-local-wi+fi-to-find-an-interference+free-channel

Posted in: Environment Setup, Random Topics

Tags: airport, apple, macbook, RSSI, wifi

“Ame ni Mo Makezu”, Not losing to the rain

No comments    yoichi

March 20th, 2011 

“Ame ni Mo Makezu” is a great piece of poetry written by Kenji Miyazawa. I believe this is probably one of the most famous Japanese poems. All Japanese who completed compulsory education must have learnt it in school, and might like and still remember it mostly.

Today I found kizuna311, a website that launched by a Hollywood Actor Ken Watanabe to encourage Japan Earthquake/Tsunami Victims(see also Ken Watanabe launches website to encourage solidarity in earthquake aftermath). In kizuna311, he read this poem, “Ame ni Mo Makezu”. Here is its youtube video. A transliteration and English translation for the text of the poem follow:

※ Source: Wikipedia Ame ni Mo Makezu

I actually saw the poem after a long interval. It was exactly the same “Ame ni Mo Makezu” as before. But this time I felt something different, something that I haven’t felt before. I read this poem more empathetically than never before. This is absolutely because of what we Japanese have experienced for last few days – Japan earthquake and tsunami. You will see in this poem the author’s ideas about how he should think of nature, how he should live, how he should support people, and whom he wants to be like. It must teach us a lot especially for this time of devastation and suffering, and let us start thinking of what we can do for the victims.

Posted in: Random Topics, Translation

Tags: earthquake, poem, tsunami

Ready to Give? – Japan Earthquake and Tsunami

No comments    yoichi

March 15th, 2011 

• Japan Platform (Japanease Only)
• Yahoo!JAPAN Volunteer(Japanease Only)
• Japan Red Cross with Google Checkout
• Japan Domestic Donation Site Collections
• Canadian Red Cross
• American Red Cross
• American Red Cross with Amazon Payment
• CARE
• Save the Chirldren Australia
• Globalgiving
• World Relief
• Convoy of Hope
• Lady Gaga Japan Earthquake Relief Wristband
• The Nippon Foundation/CANPAN
• Yahoo: Japan earthquake and tsunami: How to help
• Apple Japan relief fund through iTunes
• Salvation Army National Corp
• International Medial Corps
• Music for relief
• Paypal
• Groupon
• Donate for Japan Earthquake – Hand in Hand with DX (2011/03/18 added)
• Hong Kong Red Cross (2011/03/18 added)

Posted in: Random Topics

Tags: donation, earthquake, paypal, tsunami

A Bunch of Covers/Remixes on “Just the Two of Us”

No comments    yoichi

February 25th, 2011 

“Just the two of us” is one of my favorite songs – a Grammy Award song, originally Jazz song recorded in 1981 by Grover Washington, Jr. and Bill Withers (wikipedia).

You will be surprised to know how many people covered/remixed this song. Here is only a part of the all covers/remixes – I collected from Youtube out of my curiosity. Great song!!

• Around The Way – Really Into You
• 2pac & Kadafi – Just The Two Of Us – Dj Sixx Remix
• Kubota Toshinobu Version
• Dr. Evil – Just The Two Of Us (Austin Powers)
• jose jose – Solo tu y yo (Just The Two Of Us)
• 2009 Taco Bell Just the Two of Us
• Willy Chirino – Just the two of us (Solo tu y yo)
• Regina Belle & Steve Cole & George Duke / To Grover, With Love
• Christian McBride Version
• Mietta Version
• Tiro de Gracia Version
• Will Smith Version
• Rebirth Brass Band Version
• The Philadelphia Experiment Version
• Benjamin Siksou Version
• DanceMan Version ”じゃあ明日にすれば”

Posted in: Random Topics

Tags: jazz, song, youtube

One of the main reasons that I visited Seoul in January 2011 – “Bukchon Hanok Village”

No comments    yoichi

February 13th, 2011 

“The Accidental Couple” is one of my favorite Korean TV dramas, and “Bukchon Hanok Village” is the location for the TV darama where many key scenes were taken. That’s why I had thought about going to “Bukchon Hanok Village”, and finally I did it in January 2011. See the following pictures and compare.

The first one is the one I captured on TV screen while playing the daram(the HDD recorded).

The other one is the one I actually took in Bukchon Hanok Village, Seoul. There are building improvements going on around there, so it may look a little bit different from the one above. But it’s the same location!

Well, apart from the location for the TV drama, “Bukchon Hanok Village” is a famous Korean village in Seoul where Korean traditional houses which is called hanok have been preserved. There are lots of tourist spots and fancy cafes etc around there . It is good to go visit there even if you don’t have passion for it like me. I bet you’d like it.

See also:

• The Accidental Couple Official Website
• Bukchon Hanok Village/Samcheong-dong

Posted in: Random Topics

Tags: seoul, travel