Monday, April 2, 2012

Convenience vs Consistency In Marconi’s Magical Ether

Convenience vs Consistency In Marconi’s Magical Ether


Marconi, the fantastical genius (second in renowned and sheer infamy only to Tesla, despite Yahoo Serious's portrayal ) who brought us the ability to transmit information from one location to another without the need for miles of wire would be amazed but quite comfortable with our wireless world. After all  the first wireless phone/mediadelivery system was in use by 1922.  The tools and interfaces would no doubt astound him, yet the process and application would be as natural as reading the newspaper.  The modern 'Golden Age of Wireless'  is mother's milk to most of us - we are as afraid of its presence, with a few odd exceptions, as we are of indoor running water. So why does it so often befoul and frustrate us?


This dichotomy was brought to my attention when, in the process of teaching a class on Ethernet and Wireless essentials this past week,  I opened my #inSSIDer tool to show what our local Wi-Fi looked like.  The plan was to use the live readings as a simple example of just how interference comes about.  Well I was, admittedly, just as stunned as the class.


 



Whoa! This is what the 2.4GHz frequency range looks like in the Secaucus, NJ warehouse where I spend a good deal of my working day - a somewhat isolated space. How could the IT manager let this happen, someone wondered aloud.


I have experienced similar reactions when teaching high school students about Ethernet, specifically Wi-Fi and RF principles. I have found that even many of these Millennials were unclear on just what is going on beyond the very basic setup.  


Why would this be?




Wireless Internet Access is ubiquitous, so much so that it has become an appliance and as such is nearly invisible to most folks - until it ‘stops working’.  In other words, it is like using a telephone, you may need to know whether to dial 9 to get an outside line and the number you are calling but other than that - it just works.  Off the shelf manufactures sell us the instant gratification of ‘pushing the Little Red Button’ to set up and connect - no need to worry about what is going on behind the curtains and in fact, these boxes intimate,  it may just be dangerous to look dear Icarus.

Our own industry, one which prides itself on being the most informed on the multitude of distinct technological disciplines, is still is coming to grips with the world of Wi-Fi.  Six years ago as the install industry was still  making the hard change to Ethernet many manufactures started to introduce Wi-Fi based products. As a technical support manager  I witnessed first hand the confusion from lack of knowledge in the field and in the support room.  The initial thought and assumption was that the technology was fairly common and therefore would be in the general knowledge meme of the installers. We could not have been more wrong.  It turns out that a great majority of our clients had very little experience with wireless Internet setup, let alone Ethernet in general.  This is not a dig at the companies and individuals involved - my discussions with other offices and support personnel at other manufacturers (yes many of us chat in private forums, even with competitors -  we are professional and know where the lines are, get over it) confirmed an industry wide problem.  


As a result of this miscalculation it became common to work hour long support calls-walking an installer step by step through the basics of setting up the Wi-Fi router/ access point.  In my company a great effort was made to teach the client on the other end of the phone line just what we were doing and what each process was for - ‘...teach a man to fish...’. While this total support helped the individual, it did nothing to stem the tsunami.   The recognition that our incorrect presumptions had a detrimental effect on call times pushed us to develop an extensive training and certification program for staff and dealers. The process took about a year to show a decline in calls and service time on the basic concepts but reduce it did. Now we could deal with issues stemming from new technologies like WDS  and general RF interference which, once recognized caused apoplectic fits.   


RF and EMF interference are funny things, if you are unaware or just limited in knowledge it can be a very vexing problem. The question is just where  can you learn the essential techniques and troubleshooting without having to digest electrical engineering text books or RF circuit design manuals?  My personal path started with having the responsibility of testing wireless microphones become part of my job description. 



Unlike wireless data networks which have data detection and correction techniques built into the transmission / reception process,  audio cannot send a request for the vocals to be resent live. This means that the concepts can be learned without getting into the minutia of error checking and checksums.   Many RF mic manufactures publish pamphlets on the basics of best practices. As we gathered more and more material books and tear-sheets   I studiously and obsessively  hand copied the main points, sometimes the whole booklet, into a small sketch book. Remember this was just pre-world wide web days and portable devices were barely smaller than a breadbox. 


I have always found that just as many audio concepts can be more easily taught by first starting with real world applications of Standard POTS (Plain Old Telephone) lines so can many RF basics be explained using wireless microphones.  This may not be the exact connection you may need but it is a start. I would suggest the following primers: 


Crestron Best Practices for Installation and Setup of Crestron RF Products  (shhh, don’t tell anyone I helped write and edit this) 


Wireless Microphones and the Audio Professional


Texas Instruments has a great overview ‘deck’ entitled RF Basics, RF for Non-Engineers


Shure has some interesting documents that discuss some of the tertiary issues 


You could just trust that is will all work but then it is a question of  program or be programmed - which brings us back to the maligned IT manager we 


mentioned above. Looking at the spectrum analysis it might strike you that it  is amazing that any of the connections work at all.  The Truth is that the network administrator, like you and me, can only contain not control  the unwieldy beast of unlicensed RF. 


 


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