Sunday, January 16, 2011

Improving Wireless Reception - Part 2

At this point I am assuming you have gone through the steps of Part 1 of this exercise here and still have not improved your wireless access to your satisfaction.

Next Steps - Pick a Clear Channel
Now we need to bring up inSSIDer again.  Recall we installed this application in Improving Wireless Reception - Part 1 on Step 1.  Please see the output of inSSIDer below:

Take a look at channel 6 above.  There are overlapping SSIDs on this channel.  Let's assume for discussion sake that your SSID is HELIOS.  Note that there are other SSIDs on this channel as well.  We want to avoid this condition.  Normally a wireless router/access point will pick a clear channel but that is not always the case.  The point here is if your SSID is overlapping with other SSIDs, move your channel to a clearer channel.  If you go into the wireless settings of your wireless router/access point you can manually select what channel to use.  I, for example, put my PHOEBE access point on channel 11 which is completely clear and you can see the strong signal at about -30 RSSI.  

Once you have completed the channel change, re-survey your wireless signal in your home and see if your RSSI improves.  If it does, record the change.  Secondly you should disconnect and reconnect all your wireless clients.  Simply disconnect and reconnect to your SSID using the Windows wireless connection tools.  See below:

Simply click Disconnect and then the Connect button will display below your SSID.  See above.

Connection Issues Still Persist - Link Layer Protocol
At this point, the improvements will be more technical so you may need to read your manuals in more depth and/or read other articles on the web to help you with these steps.

Recall in Part 1 of this article we talked about the different wireless protocols.  For the consumer, they are:

  • 802.11a
  • 802.11b
  • 802.11g
  • 802.11n (sometimes called Draft N)

In Part One I did not go into detail about 802.11n.  It is the next generation of wifi access after 802.11g and provides speeds up to 6x faster that 802.11g, theoretical.  It does propagate through your walls better than 802.11g and has a double channel mode that permits connections up to 300 MBits/sec theoretical.  The specification also defines additional frequencies at 5Ghz.  You will see these wireless routers sold as "Dual Band".  I have not seen much in the way of wireless clients that support the 802.11n 5Ghz.  You will have a much clearer signal on 5Ghz, but 5Ghz frequencies do not go through walls as well as the standard 2.4Ghz frequencies.  Trade offs of course...

Here are the rules you need to follow now:

  1. Most importantly, get off 802.11b.  802.11b has the poorest signal propagation through walls.  If you have a wireless router/access point that only supports 802.11b, it's time to upgrade.  If you have a router that supports both 802.11b and 802.11(g/n) you need to disable 802.11b.  By mixing 802.11b signals with 802.11(g/n), it will reduce throughput.
  2. Accordingly, if you have wireless clients, perhaps an older laptop, that only supports 802.11b, you need to get a PCMCIA, USB, or Express Card wireless adapter that supports 802.11g/n.  Head over to you local MicroCenter or Frys and get your necessary upgrades.  The staff at Microcenter and Frys are very helpful.  Alternatively, you can purchase online at tigerdirect or newegg.  There are other online merchants of course, but I tend to stick with tigerdirect or newegg for my computer needs.  Just a matter of preference.  See below for some hardware recommendations.
  3. My general rule of thumb for wireless gear is do not buy the latest gear nor the gear that has all the bells and whistles.  I find there are more bugs in the latest gear that take time to work out.  I go for gear that has been out for approximately 2-3 years.  By doing so, more of the bugs have been worked out and this leads to higher stability.  This is especially important for your wireless router/access point.  I personally avoid the cheapest gear and avoid the most expensive gear.  Again, personal preference.
  4. Brand selection: 802.11g  This is a tough one to recommend as each hardware line of the major wireless vendors can have good and poor lines of equipment.  The classic line of wireless router that has been out for years is the Linksys WRT54Gxxxx line.  Both the older models (ebay) and the later models of this line are generally very stable.  Make sure you are running the latest firmware be it opensource dd-wrt or from Linksys.  Both have advantages and disadvantages.  For the technical minded ones, you will definitely want to use one of the open source firmwares.  Tomato and dd-wrt both have some nice "techie" features. 
  5. Brand selection:  802.11n  I have gone through several 802.11n wireless routers and they have been very unstable and subsequently I put them in my "wait for new software/firmware" box.  The only model I am going to recommend is the model I use now and has been stable.  It is the D-Link DIR-855.  I chose this model since it came out a few years ago, it has three external antennas, and they are removable to permit use of third party antennas.
  6. Antenna selection.  If possible, buy a wireless router with external antennas, the more the better.  Even better still, models that have antennas you can disconnect and install third party antennas are the best solution.  Do your home work, pull the specification details and find hardware that looks good to you.  Check reviews.  Note:  I did extensive reading on reviews and have been burned.  What I learned from this is generally see what the user rating is for the wireless router/access point.  If it is above average, then go to the vendor support forums and see what kind of complaints are posted about the gear.  Base your decision off the support forum primarily.
  7. For client wireless adapters, I do not have any recommendations.  The few that I have purchased from major brands have all worked fine.  Get the latest drivers from the manufacturer website.  Note:   if you are buying a wireless card for a desktop, you definitely need to get one that has a cable permitting the antenna to go on your desk or better yet on a shelf.  The common model, with two or three antennas sticking out of the card, are less effective because they are buried behind your computer, table, wall, cables, etc.  All these things attenuate the wireless signal and will give you poorer signal quality and throughput. 
802.11g or 802.11n
Which version should I get?  802.11g gear is cheaper and has a maximum throughput of 54Mbits/second theoretical.  Normally 802.11g is just fine for your typical internet user that reads mail, surfs the webs, pull down music from online music vendors, watches videos on youtube, etc.  Note:  802.11n will propagate through your house better than 802.11g by some margin.  If you have signal difficulties, go ahead and get 802.11n gear and run a pure 802.11n network on a clear channel.

Repeat Part 1
If you have replaced any of your wireless gear, you now need to go back through the steps of Part 1 of this article located here.

Still Hope
If you still have wireless signal difficulties after following Part 1 and 2 of this article, there is still hope in Part 3 of this article.  I will try to get it out as soon as I can.

If you are using this article and it is helping you or not, I would really appreciate some feedback.  If you are hesitant to post publicly, feel free to email me at john at mysnmp dot org.  I'd be happy to work with you individually.

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