Transmitter trips main breaker

Received a call last night, after a particularly bad thunderstorm, that WGHQ in Kingston, NY was off the air.  Earlier in the day, the transmitter had tripped the main breaker after a thunderstorm.  I arrived at the transmitter site and found the breaker tripped again.  Once the breaker was reset, the transmitter came back on and ran without any overload indications.  The transmitter is a 10 year old Nautel ND-5.

WGHQ Nautel ND-5 transmitter
WGHQ Nautel ND-5 transmitter

I was thinking breaker fatigue as the breaker is the original 1960 breaker installed when the building was built.  I reset the breaker and turned the power output down to 3 KW, thinking the reduced load might not trip the breaker until we could get a replacement.  The transmitter was on the air running as I was about to lock up and go home when I heard, but more felt through the floor, a THUMP! There I stood and watched the transmitter go dark.

At least it happened when I was there looking at it.  Because of the lightning, I was thinking something in the output network.  I reset the breaker and once again, no faults and the transmitter came back on.  Strange.  Obviously some sort of power supply issue.  Here are the clues:

  1. The B- voltage was right where it should be at 72 volts.
  2. All other readings, reflected power, forward power, power supply current are normal before and after the breaker trip
  3. No fault lights
  4. The service panel breaker, which was tripping, is rated for 70 amps, the transmitter front panel breaker which did not trip, is 50 amps.

The Nautel factory rep was thinking either breaker fatigue or the big transformer in the base of the transmitter had gone bad.  According to him, no one had ever heard of a transformer going bad in these transmitters, which makes a certain amount of sense.  Unlike a tube transmitter, which steps the B+ voltage up several times, these transmitters reduce the B- voltage by about 2/3rds or so.  With a step up situation, a surge would be multiplied many times and could very easily punch a hole in the transformer’s secondary winding insulation.  I have, in fact, experienced this on at least two occasions.

That leaves the wiring between the transmitter and the service panel.  I double checked the panel breaker with my volt meter to ensure that the voltage was indeed off.  Then I removed each phase from the connection lugs in the transmitter and tested the wire to ground with my Fluke 77 DVM.  Sure enough, two of the phases showed resistance of 1.2 and 1.7 MΩ to ground were it should have been infinite.  Further, when I took the cover off of the service panel, I found a dead mouse.  Unfortunately, I didn’t have any #4 THHN and all the home improvement stores were closed by that time, so it had to wait until morning.

The thunderstorm seems to be a coincidence.

After we pulled the wire out of the conduit, we found this:

mouse chewed feces encrusted electrical cable
Mouse chewed feces encrusted electrical cable

It is a little hard to see, but that shiny spot is copper.  The cable jacket is chewed back quite a ways and the entire thing is encrusted in mouse feces and urine.  I love to work on stuff like this.  LOVE IT!  Hantavirus, here we come!  That reminds me, I need to get some of those blue latex exam gloves and throw them in the truck…  Anyway, far back in the conduit running through the concrete floor where it bends to go up to the service panel, the mice apparently had a nest.  They got into the conduit under the transmitter, where it transitioned from 3 inch rigid to 1 1/4 inch flexible metal without benefit of a junction box or proper fitting.

We pulled new copper conductors in and installed a proper junction/transition between the 3 inch and 1 1/4 inch conduit.  The service panel was also missing several knockouts of various sizes, which were sealed with knockout seals.  The transmitter was back on the air at full power about 16 hours after it went off.  Unfortunately, the station has no back up transmitter, so they were off for that period of time.  Perhaps now they will look into a backup transmitter or at least an exterminator, but probably not.

Opting out of Smartphone Spyware

A while ago, I was extolling the virtues of my Android smartphone. I have to say, I am still pleased with the unit, having a mini-computer/camera/phone/calculator etc is handy. It makes life easy to find a needed part on Mouser.com, order it and get it the next day.  I can snap a picture of something and send to somebody in less than a minute.  When trouble shooting a transmitter, sending a picture to the factory rep cuts down on the back and forth and brings the effort directly to the point.

I have also blogged about my mediocre Pandora experience.  Now, it seems there is another reason to be weary of the mighty Pandora machine.

The Wall Street Journal has a good article about what these companies are doing with your data.

Both the Android and iPhone versions of Pandora, a popular music app, sent age, gender, location and phone identifiers to various ad networks.

Read the whole thing, it is enlightening.

Is my Smartphone spying on me?  Apparently so.  Frankly, I’ve had enough of this.  There is nothing compelling or even terribly unique about Pandora.  I’ve found the Pandora listening experience to be adequate, but certainly not worth all the hoopla it gets.  Being constantly bombarded by advertisers selling all sorts of garbage is becoming annoying.  I’ve gone through and deleted all apps that access personal data of any kind, including Pandora.   There are a few which are hard rooted in the phone such as Skype mobile and Facebook which can’t be deleted.  Skype mobile can’t even be deactivated, as soon as the program is ended, it restarts on it’s own.

So, is Skype mobile recording everything I do and sending to some black hole somewhere?  I don’t know.  If it is,  it is likely boring somebody half to death as most of my life is pretty mundane.

Update: I rooted my phone, which was far easier than I thought it would be, and deleted all the programs I didn’t like.

Heads? Tails? I don’t really know

When confronted with something like this:

Transmitter Remote Control Wiring
Transmitter Remote Control Wiring

It is often faster to cut all the old wiring away and start over.  This is a transmitter remote control system which was initially installed in the early 70’s.  Over the years, it was added to, subtracted from, divided, multiplied, sliced, diced, etc.  In the end, the existing wiring documentation did not match most of what was there.  Additional to that, several of those terminals have 120 volts and I found at least one instance of 208 volts.

Therefore, we began by removing all of the wiring from the backup transmitter, running a temporary audio wire and switching to the backup.  Then, with all the breakers turned off, all the wiring was removed from the main transmitter, phasor and remote control interface and we started over:

Transmitter site remote control interfaces
Transmitter site remote control interfaces

Once upon a time, some engineer built these remote control interfaces, which are quite nice.  We decided to re-use them where 120 volt control is required.  When completed, I will tape over the terminal and label them accordingly.  The main transmitter uses open collector control, therefore, it can be wired directly to the Burk ARC-16 IP-8 panel.

Burk IP-8 Remote Control interface panels
Burk IP-8 Remote Control interface panels

The Burk unit, as wired with the main transmitter, common point, tower lights, phasor and antenna monitor.  The project has not been without some small off air incidents, once while we removed a metal name plate that had fallen into an inductor in the phasor.  All in all, progress is being made.