The control channel plays air traffic controller

pic credit:
pic credit:

last covered how the control channel is the software brains behind modern day trunked radio repeaters.  But how exactly does a control channel work?  The system itself can be compared to an air traffic controller.


An air traffic controller is the logistical gateway for airplane movement both on the ground and in the air.  The airplane pilot may steer the plane, but he isn’t allowed to move or fly until authorized by the controller.  The controller also keeps planes separated on the ground and in the air ensuring no ramp or mid-air collisions occur.

The Control Channel

The control channel of a repeater performs these same operations.  No communication occurs until the control channel gives the go ahead just as an air traffic controller would for airplanes.  From the moment the two-way radio is turned on, the radio checks in with the control channel and electronically asks permission to join the radio network.  Once approved by the controller, the radio is told to hold until for its next task is issued by the control channel.  Just like an airplane pilot, the two-way radio must communicate with the controller before being allowed to talk with other radios on the network.  And similar to runways at an airport, the control channels separates radio traffic to different frequencies (think runways) ensuring no two-way radio traffic collides with each other.

It gets even better

Certain radio towers are part of a regional network and have the potential to be part of a global network using IP based technologies.  This regional network has its own separate control channel which regulates regional traffic just like ATC regions (aka: air centers).

Why the Need?

Radio tower destroyed during the 8+ hour pounding of winds and rain during hurricane Katrina. pic credit: getty images
Radio tower destroyed during the 8+ hour pounding of winds and rain during category 5 hurricane Katrina – the costliest natural disaster in US history.
pic credit: getty images

I agree the systems I am describing are much more complicated than 1990 systems, but there is a need as evidenced in hurricane Katrina when all communication stopped including cell phones.  Temporary satellite towers were strategically positioned in the affected areas after days of no power, towers, or communication in the area.  The resulting advancement of the MSWIN radio and data network is a good example of mission-critical vendor neutral communication network.  Pre-trunk systems were sporadically located and loosely funded resulting in lackluster communication across the full state of MS.  There is a lot of politics involved considering this is a government funded entity working through governmental delays and bureaucratic administration, but today’s MSWIN network is extremely advanced post-Katrina.

noaa Katrina path
noaa Katrina path

As a final side note, you may be wondering how Mississippi inherited the MSWIN network considering New Orleans got all the news coverage of Katrina.  That’s cause the majority of the state was without power in the aftermath as highlighted by Katrina’s path in the adjacent picture.  As a result, most of Mississippi was dark and off-grid for days in major cities and weeks in rural areas.

Spirit Airlines – Myth vs Reality from DFW to LAX 

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We’re all looking for ways to be cheaper when flying. I am a Dave Ramsey fan which means I’m more frugal than the average person although my close friends might refer to me as cheap.  In my frugal nature, I researched the cheapest flights to and from Los Angeles. I also looked at on-time ratings using Flight Aware considering I needed to be on the ground and in a rental car as quick as possible to make an appointment.

I read so many scathing articles about Spirit Airlines prior to my trip from DFW to LAX.  Some of the articles were so bad that I even thought about paying more to fly other airlines – mainly American which was only $50 one way to include one personal item and a carry on. This article will hopefully set the record straight for Spirit.

The flight I booked was only $38 one way. That’s so frugal that I couldn’t believe it at first which made me nervous.  The flight even got cheaper over the three weeks I watched it. The lowest fare I saw two days prior to departure was the $34.10.  The price steadily climbed over 48 hours as the plane filled. Last price I saw was around $180. The funny thing is the seat directly beside me was empty, the row diagonal behind me only had one person lounging across three seats, and four other rows had empty seats for our 6:30 am flight. Considering the dramatic change in price, I would guess the increase was generated by an automated system to catch those in need of last minute flights.

The Luggage

My black backpack “personal item” storage location

Spirit has strict limits on luggage which is part of the way they keep fares low.  I packed a small backpack for my day trip so I could avoid any carry-on or baggage fees. My backpack (pictured) falls into the free “personal item” category – no extra fees.  My backpack was also technically two inches too long according to Spirit website guidelines, but I took a chance since it is very thin.

I lined up to board the plane and nobody questioned or measured my backpack. Some carry-on items (not personal items) of other customers were being measured at the gate while I boarded, but I was never given a second look. As you can tell from the pictures, the bag fit well under the seat in front of me which is the required for personal items.

The Splurge

I’m 6 foot 4 with long legs so confined spaces are not my thing. I originally expected to take any assigned seat until I researched that Spirit seats are the tightest of any airlines at 28 inches between seats (back to front). They gotta make money somehow so I can’t fault them.

Considering I was testing Spirit on this flight and didn’t know what I was getting into, I upgraded online the day before my flight for $20 so I could sit at the exit row. Even with long legs, I had plenty of space on the exit row!   The only issue with my long legs was the food down table being mounted lower than normal causing it to sit on top of my knee. I could be wrong, but I don’t remember having that problem with Delta and American Airlines A320 jets.

Food tray mounted low – sitting on top of my knee

Point to note: our equipment for this flight was an A320 which accommodates two exit rows – one directly behind the other. I chose the second exit row which means the person behind me was in the smaller 28″ seats. I had plenty of leg room in my exit row, but I felt someone else’s knee pressing into my back a few times during the flight. If you’re booking an exit row on the A320, choose the first row.

The Verdict

Overall, I have to say I was impressed and this was a very pleasant flight for an extremely low $38.  Flight attendants were very nice and polite, and the captain communicated well.

Spirit does business well. I expected a WalMart style airline based on the reviews I read prior to flying, but Spirit is straight up like their website claims. This leads me to think most of the complaints I saw online were riders who either didn’t read policies before flying or thought they were special and could get away with breaking the rules. That’s just not my style.

As for me flying out of DFW to Los Angeles, I will most likely book American next time simply because they normally charge $50 for a similar flight, offer a free carry-on item, plus a personal item, free snacks, and because I have a prior relationship with them even though they previously broke a brand new checked bag of mine… errr. Still bitter, but they credited me after 30 minutes of me being a donkey at the luggage counter.

Back on point, Spirit is exactly what they claim: no frills and cost saving. You’ll be fine as long as you follow the guidelines on the Spirit Airlines website which includes printing your boarding pass at home plus showing up at the specified check-in time.

The Details

In case you wanted to know, this article was based on flight 867 on February 23, 2016.  We had an on time departure and arrival.  By appearance, customers were 60 percent families / 40 percent professional.

The 2nd Exit Row

First amateur radio repeater being sent to space

satToday in News You Can’t Use! This really is an impressive feat although ham radio is not near as popular as it once was.

“It was recently announced that researchers at the Ted and Karyn Hume Center for National Security and Technology, part of Virginia Tech University are preparing to send an amateur radio transponder into a geosynchronous orbit in 2017.”

Take a look at the full article at this link:

Mass Transit Gets Personal with PRT

Most people don’t like public transportation for valid reasons. Buses are slow, public transit trains can be crowded, schedules inconsistent, and many times transit just does not feel safe. And I almost forgot to mention the fact that people cough, sneeze, talk too much, and sometimes just smell bad. But maybe you’ll rethink public transit based on the skyTran system developed in conjunction with the NASA Ames Research Center.  The skyTran PRT  (Personal Rapid Transit) system is not just theory any more since it’s beta version is currently being implemented on the corporate grounds of the Israel Aerospace Industries (IAI).

skyTran loading station courtesy
skyTran demo loading station courtesy

The skyTran system uses privately enclosed 2 person occupancy vehicles, better known as pods, that offer the feel and comfort of personal flying cars similar in design to those from the twentieth century Hanna-Barbera Jetsons cartoon.  Don’t get too excited though since these pods are not free flying but are mounted against tall trackways.  This magnetic propelled monorail system is the most efficient PRT system I have explored to date with the most realistic deployment methods in addition to solar power source options offering an independent self-driven power grid.  And skyTran time-in-transit will not be slow due to unwanted bus/train stops commonly seen on subway and bus routes.  The system was designed with the ability of zooming along at 150 miles per hour at 200 mpg nonstop between it’s originating and destination travel points.

eu poll

The key to this system and the reason I think it has a future is the transportation designer’s plan to operate elevated tracks parallel to major roadways.  This plan gives skyTran the ability to take advantage of existing power infrastructure if solar is not an option.  Existing freeway light polls can be replaced with hanging skyTran tracks avoiding the need for legal right of way delays while also tapping into existing power sources when needed.  Installing numerous ground level loading/unloading stations on physically separate tracks is also an efficiency improvement of PRT systems to keep other pods moving on the elevated tracks. The skyTran PRT system is also expected to offer on demand service via smartphone apps. If you prefer traveling with others, skyTran has a computer-linked caravan option where multiple 2-person units will be called to the same point within the PRT grid.

Pods and PRT systems have existed for years like the early Disney WEDway PeopleMover and more recently PRTs found at Heathrow Airport in London, but older systems were built with limited scope and operate in sensor guided environments which seem too expensive to develop on a large scale.  The cost of skyTran implementation will be much less per mile compared to existing brick-and-mortar roadways or subway tunnels, and I can only imagine these highly efficient PRT systems would be able to dynamically cross cities in ways impossible for ground based vehicles.  Think of riding a PRT vehicle across shallow reservoirs, drainage ditches, or even along grass covered power-line right of ways.  There is no incentive for an electricity provider to build public roads or HOV lanes on their land to ease ground traffic burdens, but energy companies and cities could profit from lease fees for PRT installations in dense urban areas using existing infrastructure towers.

If Uber’s success has proven anything, it’s the fact that people are still willing to pay for what they deem good quality and acceptable cost public transit.  We have no idea what the future holds for PRTs since new technology adoption for any industry can be an uphill battle, but I have high hopes for the future of skyTran.

Hungry For More?
If you still want to learn more about future transportation technologies, check out the Heathrow PRT experience or scratch your itch by watching this video: