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Behind the Scenes: Life with a Transmitter

Hey Everyone! We’ve been spending a lot of time down at our transmitter getting it back up to optimal shape. I thought it’d be fun to post some pictures of the action for all to see, so here goes!

TX Cabinet B - E2V IOTThis is our backup transmitter. Both of our transmitters are the Visionary-class IOT (Inductive Output Tube) based transmitters manufactured by Axcera. They operate at roughly 20Kw-22Kw at full power.

TX Fried Beam Supply Board 1TX Fried Beam Supply Board 2These are High Voltage beam supply boards that were damaged delivery of high-voltage power to our transmitter for proper transmission. Note the blue arrows pointing to the scorch marks where the high voltage damaged the boards.

TX Cabinet A High Voltage Power Line FailureThis is a piece of the high voltage wire that runs from the high voltage beam supply (specifically attached to the boards above). This was also damaged during the storm, as when the beam supply boards suffered the arcing and damage it caused the wire to arc in the conduit as well. Note the hole in the insulation of the cabling.

TX Surge Supression BoardsTX Engineer Working on Surge Supression Boards
Surge-Suppression boards (right): These boards protect our transmitter in the event of a sudden surge in power. These boards had to be replaced in both our Primary and our Backup transmitters as they were damaged during the storm.

Here our on-site engineer, Kevin, is replacing the surge-suppression boards in the backup transmitter. (left)

TX Crowbar Assembly TX Thyratron Cooling Fan This is a crowbar assembly (left). The crowbar assembly is used to prevent an over-voltage condition within the transmitter cabinet itself. This particular crowbar assembly utilizes a thyratron tube. The cooling fan (right) went bad in the backup transmitter, causing an intermittent fault in the crowbar assembly. The tube has to remain at a constant temperature in order to work properly, and as a safety measure the transmitter will not operate with out a working crowbar assembly.

TX High Voltage FusesWhen the beam supply boards failed, causing the high voltage cabling to arc in the conduit blowing a hole in the insulation, the fuses for the high-voltage switch were also blown. We had to replace three high-voltage fuses in the main power supply switch that feeds the backup transmitter itself.

TX Flow ControlAfter we replaced all of the faulty equipment that was damaged due to the storms, we had some final tweaks to perform on the coolant system to ensure optimal coolant flow.

TX Cabinet B Full Power TX Cabinet A Full PowerAnd after our unfortunate downtime of almost eleven days total, we have two very happy working transmitters again. I hope that you’ve enjoyed the peak into our world of transmitters, and how truly amazing they are. In a way, they are are just as (if not more) complex than your everyday automobile. Consider all of the parts, their points of failure, and how any one, or a combination of many can mean minimal or prolonged downtime.

Again, thanks to all of our viewers for the kind words, support, offerings of assistance, and most of all, dedication to MiND as we worked through this extremely painful period of our life.

MiND TV is Off-Air

Last week MiND TV had a serious failure of its transmitter systems. This has caused all MiND channels to be off-air since that time: MiND (35.1), NHK World (35.2), France 24 (35.3), RT (35.4) and MHz World (35.5). We are doing everything we can to correct the situation and get back on-air as soon as possible.

If you would like to know more, please continue reading.

In the 21st century, we tend to take television distribution for granted, but it involves a complicated technical process. Briefly, here’s how our system works:

1. We build channel 35.1, MiND, from programs and interstitials at our headquarters in Philadelphia. We receive our sub-channels and then simply redistribute them: NHK from Japan, France 24 from Paris, RT from Washington DC, and MHz Worldview from Virginia.

2. In our master control, we combine all five these channels into a single transmission which travels via a dedicated broadband line from our headquarters (about a mile north of the Liberty Bell) to our broadcast tower (near Manayunk).

3. The transmitter sends the whole signal to your home. If you are watching over the air, with a home antenna, and to the cable and satellite providers who then send it to you through Comcast, Verizon, DirecTV, Dish Network, CableVision and RCN.

We apologize for this inconvenience and assure all of our viewers that we are working very hard to reestablish our signal as soon as possible. Thank you for watching the MiND channels.

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