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. 

 

White Spaces - RF beyond the Aesthetics

 

White Spaces,  Sounds like something your Art History professor would use to describe ‘the   power’ of an unpainted space on a Jackson Pollock.  

In fact White Spaces is the name for a contentiously battled over area of RF (Radio Frequency Spectrum) and yes it effects you and your AV business.

Until just a few years ago television stations broadcast their signals via three separate signals, one each for Picture, Color information and Sound. These three signals would be recombined inside the circuitry of your TV  to produce the complete picture.  These three RF spikes, creating mountains and valleys could be clearly seen on an off air oscilloscope.  The valleys and spaces between the channel signals is where many wireless devices would ‘sit’.  In large metropolitan areas where every possible channel was used, such spaces were invaluable.  When it came to wireless microphones, this was doubly so.  

Then came digital television.  This beast, not to be confused with HDTV -(the former can carry the latter but it may not always be the case), generates one signal with all the information.  Great! you might think - with two less signals to worry about there will be more room for other lower powered RF devices, right?

Um, No.  

While there is now only one signal it takes up a wide swath of space in a continuous signal. Bummer no? Yet there is a bright hope here.  The FCC mandated that all analog broadcasts (the three spikes) were to have ceased broadcast by June 26th, 2009. The plan is to sell off all the remaining ‘empty’ space to facilitate new communications technologies and less the RF congestion that now plagues wireless.  

Great, Right?!, Maybe.

Manufactures and audio industry folks have been raising a ruckus to insure that a defined space is available for the use of itinerant wireless devices such as microphones and intercom systems - such as those used at live events.  Sadly it took a small skirmish but it appears things have been finally worked out.

I learned about the true value of the analog television signals on  February 26, 1993, the day the World Trade Center was bombed.  One of my responsibilities as a rental tech was to test and calibrate wireless mic systems going out on jobs.  One of the tools we used ( and actually still have) was an off air oscilloscope or IFR, to insure that the IFR was itself calibrated we would tune it to a TV channel’s Picture RF spike.  Once we knew that the RF spike from. say channel four was reading accurate - we could then be confident that our mic signal was accurate and tune it accordingly.  On that February day I was still only just becoming comfortable with the operation of the IFR.  

As usual I brought up the Television channel to see that the unit was operating  as expected when it happened, the spikes - all three dipped then disappeared.  I checked a few more channels and they too were gone.  “Oh no”, I thought, “i have broken a $10k piece of test gear”.  With a mild sense of panic and depression I told the service manager of my actions.  He was a bit irked with me to say the least and stormed to my test bench.  He found the same thing I did until he brought up NY channel two, he then brought up the audio - which is where we heard the news that the WTC had experienced an explosion that had shut down the transmitter atop tower one. (Channel 2 still used the antenna atop the Empire State Building).  That is when we looked  out the office window which had a direct view of the WTC, to see smoke billowing up. I recall this event every time I look at a oscilloscope and it is the mental image I have of when I think of what the analog transmission shut down must have looked like.

Now that I am back in the event staging / live events world I have an renewed interest in just how the new landscape of RF should be handled and lucky for me the good people at AV Nation have a great podcast special on just this topic. The special broadcast includes Sennheiser's Eric Reese  and Kent Margraves with host Michael Drainer discussing  the FCC laws and tips to get your wireless to work flawlessly.  I highly recommend it to anyone who works with audio for live events, this is great stuff.

 

 

From my Tumblr Blog - Tucker's Tertiary

 

Five Year Olds Musical Mashup Breaks the Law of Conversation of Mass and Energy

We have played music, specifically John Coltrane’s Black Peals –(Hackensack, 1958. Recorded by Rudy Van Gelder – Most likely on a band saw machine)- for my oldest from in utero to the present day. Rooster seems to have an innate sense of musical structure and is drawn to instruments as well as humming song fragments when he is concentrating.

We have introduced a variety of formats and musical genres to him such as Jonny Cash country, bluegrass, rock, pop and a little bit of Classical/ Opera. Some of his new favorites are Etta James and Kidz Bop 12.

Yesterday I happen to catch him half humming, half sing song combining the Black Pearl intro with Sunday Lover. When I asked him what he was singing he returned with a question –‘Dadu’ –(what my kids call me) – ‘do you think Kidz Bop can sing Etta James songs?’ I said I was not sure but we could email them and ask.

I write about this story not to coquettishly point out my son as a prodigy or musical genius but at the power of music, however glancing, can have on everyone but especially a child. Rooster –(my name for my oldest)- hums Coltrane music to his school friends and adults, telling them with a joy only a child can produce who it is and that ‘Trane rocks’. This does not happen every day but enough for me to note it.

It only takes one innocent and joyful person to spread the virus of culture – the joy of learning. So many doors of thought are opened up for me from my children’s honest combining of ideas. Concepts we as adults reject outright because we know that they should not go together are freely combined by children – creating new forms if only transitory in its existence. Perhaps I am simply channeling Art Linkletter in my own way but I am learning so much from watching my children process what we offer them, in return gifting us with fantastical creations we are the better for being exposed to.

A child’s imagination frequently and fragrantly breaks the law of conservation of mass and matter. Much like Arthur dent learning to fly we adults have to relearn that by flying simply as a result of not hitting the ground means that you can. How many interviews with innovative business people have you heard say, if we knew what we were doing – we would not have done it.

The laws of physics be dammed, create your own rules, make your own universes