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Chapter 19: Catch a Wave-Guide and You are Sitting on Top of the World

Tales From the Towers Chapter 19: Catch a Wave-Guide and You are Sitting on Top of the World

The Beach Boys are going to hate me for this but I’ve been waiting for years to use that line.  I also wanted to title it, “Look Ma, no mesh” but I should have used that one several articles ago.  It’s not that I have anything against mesh as there is an application for almost every technology.  At this point in the industry and the economy, however, it’s time to get past a word very few non-technical people understand and the excessive associated cost of it.  Anyway, this article is about wave-guide antennas so let’s get back to that.


Vivato was a waveguide based antenna.  I have had Securawave waveguide antennas installed for about 7 years.  I became a believer when I connected a car at 2 miles and my laptop inside a Jack-in-the-Box at 1 mile.  The horizontal polarity was a huge advantage since most wireless access points (APs) were vertical polarity.  Securawave is no longer in business so I’m hoarding the last few units I have to support units I’ve deployed out in the field.  Not that solid aluminum blocks have a tendency to fail as I suspect they will last longer than the buildings they are mounted on (they just don’t make them like this anymore), but  I am keeping the spare unit in case of physical damage to those currently deployed.  I don’t need dual-polarity and 2×2 MIMO yet in these areas because Qwest hasn’t figured out how to get more then 3Mbps over the so-called HD Internet services and I’m not ready to mortgage my house for their other service offerings.  Of course it’s hard to dial the phone when your eyes are tearing up from laughter when they advertise their new 40Mbps service.  Eighteen months ago they couldn’t even keep a 640Kbps DSL line running properly in the middle of Phoenix less than 1 mile from Sky Harbor Airport.

Historically, waveguide antennas were expensive to make which is probably why they were not so popular. Ubiquiti seems to be bringing it back with its new omni-directional dual-polarity antennas.  We know that dual-polarity has better penetrating and range capability than single polarity.  So extending that into an omni-directional antenna seems like a great idea.  Since there aren’t any other 2×2 MIMO omni-directional dual-polarity antennas that I know about, this is really cool from a technical, design, and financial standpoint.  It’s also how we are going to keep Guerilla WiFi cost-effective and make it better.

The new Ubiquiti omni-directional antenna isn’t a true waveguide antenna.  Since it needs both polarities, half the antenna is basically two 180 degree vertical polarity sector antennas back to back with dual 180 degree waveguide antennas.  Since it’s not out yet, I haven’t tested the unit but the pre-spec guess is it’s around 12-13dbi.  That means the effective LOS range with dual polarity is going to be about 30% farther than an omni with 15dBi of gain for a couple of reasons.  However, real world performance is going to be significantly better since dual-polarity will definitely penetrate vegetation better, reduce noise off-polarity, and reduce fading.  If the client is using a dual-polarity indoor radio, then not only will range be better, noise will be significantly reduced even further.  I smell a huge performance improvement in the air for Guerilla WiFi.

Let’s go back to Chapter 1 of Tales from the Towers where we designed a $10K per square mile system.  In that design, we used a 15dBi omni-directional antenna with a single polarity omni-directional.  This design was using a single stream 802.11 b/g/n design.  With the new dual-polarity omni-directional antenna, we still use a single radio for our AP but we have doubled the throughput with a 2×2 MIMO stream.  In addition, we have doubled the throughput of every hop and added an additional hop.  Even at the 4th hop we are still delivering up to 10Mbps.  Keep in mind that at a 10-1 oversell rate, that means that you can sell twenty clients 5Mbps at the end of the chain. Although pricing hasn’t been released, I’m pretty sure this antenna with a Rocket M2 radio will still cost less than $300.  Double the performance of the original Guerilla WiFi at no additional cost and it’s better than triple coupon day at my local grocery.

Think about that for a moment.  If we only had one egress point for our network, our base network was limited to 3 hops with the same capacity at the end.  This single antenna, which allows us to change from a single stream 802.11b/g/n radio to a 2×2 AP, doubles that throughput, thus extending our single AP model out even further and doubling bandwidth down the chain.  Our egress point can also use multiple radios which can triple the throughput to 3 times that for $300-$600 more without even getting into out next topic, GPS Synchronization.  So for less than $11,000 per square mile, the system now supports 180-300Mbps, depending on the clients.

So if your town is 20 square miles and this whole system cost $250,000 to put in, then it’s a no-brainer simply for cameras, security, mobile access, and department efficiency.  Of course, if it goes through federal funding, has government engineers add in the fact that it has to support mesh (pointless in this and most designs but adds significant costs), throws in ridiculous temperature requirements like -30C for Phoenix or 80 degrees centigrade when -75 degrees centigrade would work fine, and requires copious amounts of paperwork to tell 14 different government agencies that you are paying wages equal to union scale even though you pay your guys more than that, then it’s going to cost $1,000,000 (my English teachers just had heart attacks over that sentence).  If you can sense my frustration with federal rules that require union contractor shops to do work that is clearly better suited to IT companies, then you are very astute.  This is why projects involving the government cost so much and take so long.

If this is a for-profit network, $250,000 to cover 20 square miles with this level of bandwidth is pretty impressive.  It’s fairly easy and cheap to add 100Mbps backhaul to each square mile for a total of 2GBps for the entire system.  Realistically, I would guess that you would get about 500Mbps before the price starts going up for full-duplex links.  Keep in mind that we are back to the core idea of an inexpensive municipal deployment.

Using numbers from previous articles, let’s assume 800 potential clients per square mile.  If we get 10% of that base at $30 per month, that’s $48,000 per month.  With this type of system, only a very small percentage of clients are going to need truck rolls.  Total revenue on this network is almost $600,000 per year.  If users have to get client radios, then they start at $30 for 802.11n 1×1 Vertical Polarity CPE’s.  For about $80, you can include a window mount and get 2×2 MIMO.   In most environments, I would be surprised if truck rolls needed to be done on more than 10% of the clients.  Even if you add in the cost of the client radios, this system should be cash flow positive at 800 clients and should pay for itself at 2400 clients within 12 months.  This just covers residential and doesn’t even get into business revenue.  The numbers are now speaking to me so it’s time to kick the venture capital market back into high gear.

Also consider this, the 16 access points per square mile strategy now covers a higher percentage of deployments, especially profit oriented ones.  If you live in the middle of high-density city, then you would want more APs per square mile for density or you fall back on the super AP concept described in previous articles.  Since WiFi is far more unpredictable that point-to-point (PTP) radio frequency modeling, there is nothing wrong with installing 16 APs and then site surveying to see if there are coverage gaps than hinder more revenue.

Cell phone companies don’t cover every square inch of every house on the planet.  It’s not cost effective.  They deploy with the best models they have and then decide if it’s profitable after field testing to fix poor signal areas.  WiFi should be deployed the same way.  Put up 16 APs, field test, check the areas with poor coverage, and then decide if it’s worth another $300 in equipment to cover that area.  If an area has higher usage, add in a triple-radio AP upgrade for a few hundred dollars more.  If an area really just needs more signal gain, look at adding a beam-forming AP just for a specific direction.  There are many options but all of them would be based on sound profitability principals.  There is nothing wrong with walking away from 2 customers that might cost $3000 to add additional infrastructure to cover.

I have 2 “Pet Peeves of Week” I have to get off my chest.  Before I get to Pet Peeve No.1, let me explain Pet Peeve No. 2: 99.999% uptime.  I was asked to design a system where I have to guarantee the CPEs that have 99.999% uptime.  Since the wireless industry has new equipment out every few months, very little of what I would deploy today has enough history for me to put my reputation behind that request.  I’m not talking about PTP full-duplex $10,000 and put links but $50-$400 CPEs.  First off, anything less than 802.11n is too old and too slow for this type of video application.  Second, anything that’s 802.11n hasn’t been around long enough to know how it’s going to run 3 years from now.  It’s kind of a catch-22 situation.  That means using cameras with built-in recorders that are going to cost three times as much or more than using lower priced cameras with CPEs.  Unfortunately there is no product history out there than guarantees that.  The reality is that all the radios I work with rarely, if ever, just simply go offline if installed correctly.  That doesn’t mean that they aren’t going to down for planned firmware upgrades or other system changes.  However, the 99.999% uptime request didn’t stipulate whether planned maintenance was included.

Now on to Pet Peeve No. 1. I mentioned it earlier: municipal bids that ask for mesh when every AP connected has a directional antenna.  To everyone who keeps adding this expensive request into these bids, it’s a waste of money taxpayers’ money and costs the city a lot more to support in the long run.  When you add a directional antenna to an AP or CPE, it’s a PTP or PTMP design, regardless of what firmware is on there.  There is no mesh because the radio can’t connect to anything it’s not pointed at.  By adding the mesh requirement, you are either getting the most expensive product out there or White Box APs with custom open-source mesh firmware that is cheaper.  I’m not saying there isn’t a place for mesh, but don’t eliminate other options like WDS.  It’s not your money you are spending; it’s ours, the taxpayers.  Let the industry and a wireless engineer decide what the best product for the design is.  It shouldn’t be the salesperson that took you out to lunch last week and has shiny brochures.  If mesh is appropriate and the best fit, let the companies bidding on the project put that down.  If WDS will work just as well or a PTMP design is better, they will bid that.  So can anyone guessed what crossed my desk again this week?  I know I’m beating my head against the wall on this since arguing with government is like trying to tell a 3 year old that candy isn’t good for them.

So we have come full circle on Guerilla WiFi from $10,000 per square mile to $50,000 per square mile and now back to $10,000 per square mile with double the performance.  If this doesn’t kick the industry back into high gear, I’m not sure what will.  Next we will cover GPS sync and how that affects deployments strategies.

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