Andrea and I had spent the night in Denver and decided to see a few sights on her birthday weekend.

First up, BD’s Mongolian Grill!  If you’ve never been to a Mongolian Grill restaurant before, it’s quite the experience!  You pick your (raw) food including noodles, meats and veggies from a buffet.  Next you pick sauces.  Workers cook it on a large flat grill right in front of you.  The first time I brought someone to one of these restaurants, they were sure I was trying to serve them raw food until I explained that they grill it after you make your selections!

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I had JUST returned to Laramie when I received a call from one of our other engineers informing me that a listener had called to report (another) outage in Rock Springs.  Great.  Time to turn right back around and make the 3 hour drive once again…

Well, at least I was treated to a beautiful sunset on the way back to the site…

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I had brought the transmitter’s controller back to Laramie for some additional troubleshooting.  Testing revealed that the issue was not in the controller.  I spent some time looking at the schematics for the transmitter and had a theory…There was one other place where the issue could be occurring now that I had ruled out problems with the controller itself.  The blower would not start.  If the blower doesn’t start, nothing else on the transmitter will power up.  One thing after the controller that could prevent the blower from starting is the 3 phase voltage monitor.  This device ensures that power is present on all 3 phases of the incoming power feed and that the rotation is correct.  If these conditions are not met, SEVERE damage to the transmitter can occur.

I had checked this component earlier but apparently missed something.  Once I found the blown main fuse I did not think to revisit the voltage monitor to check if it was now seeing all 3 legs of power.  The schematic diagram revealed three fuses in line with the samples to the voltage monitor.  Apparently two of those three fuses were blown in addition to the fuse in the main disconnect!

At the site in my trusty white chariot, UW88 (freshly back from an oil change)

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Earlier this week our Rock Springs transmitter went off the air.  I was out of town but sent one of our other engineers to check it out.  He wasn’t able to diagnose the issue with the main transmitter but was able to get our HD transmitter at the site on the air in analog mode to provide a reduced power signal until the main transmitter can be repaired.  I went to the site today to attempt to restore service.

Made it to the KUWZ site…A nice clear day without too much wind.  Pretty rare to have a calm day without wind here in Wyoming!

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I don’t often get an opportunity to do much repair on the bench any more but always enjoy it when I do get a chance to troubleshoot equipment at a component level.  A friend of mine gave me a Crown K1 amplifier that was completely non-functional.  This amplifier was released in 1994 and was revolutionary for its time.  It is completely convection cooled.  Most amplifiers have at least one fan.   Output is up to 750 watts in stereo (2 ohms per channel) or 1500 watts in mono (4 ohms bridged).  It produces this output while drawing less than 10 amps at maximum output and continuing to work even in harsh conditions (high heat, etc).  This amplifier sold for almost $2,000 new and has a reputation for good performance.

One (non-functional) Crown K1 Power Amplifier

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After adding HD2 and HD3 to 91.3 KUWT, it was time to rebuild the translator in Riverton so it could rebroadcast Jazz Wyoming via KUWT-HD3 as an analog signal to the people of Riverton and the surrounding area.

It’s a gorgeous day to do this install…A butterfly sits on a thistle at the site…

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Our Copper Mountain transmitter site (KUWT, Thermopolis) had been giving us a number of issues for the past few months.  These issues were somewhat inconvenient to say the least while I was trying to add both an HD2 (Classical) and HD3 (Jazz) service to the site.

The latest technical issue was a failed power supply…This won’t generally take the transmitter off the air but it will reduce the power output until the fault is repaired.

First task, replace the failed power supply module.  This one had actually developed a fault that shorted one of the input connections to ground.  You can probably imagine this isn’t a good thing…Look at the blackened fuse on the right (my mistake after trying to swap the fuse hot before actually replacing the power supply)

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Our KUWC station in Casper, Wyoming has been broadcasting in HD for quite a while.  If you aren’t familiar with HD Radio technology it allows a digital signal to be broadcast alongside the existing analog radio signal.  The new digital signal can also carry additional channels of audio.  KUWC had been broadcasting an HD2 signal carrying classical programming but we wanted to investigate adding Jazz as an HD3 signal.  Unfortunately to add the third signal we would need to reduce the bandwidth of the existing two signals.  We performed some listening tests to ensure the quality of the existing two services would not be impacted.  Those tests were extremely positive so we proceeded with adding the third service.  Since there was already an HD2 signal, no additional equipment (other than an audio source) was required for the 3rd HD signal.

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Our site on Copper Mountain experienced a failure of some HD Radio equipment.  I traveled to the site to attempt to restore HD service.

One dead NE-IBOC signal generator…My only real recourse is to replace the hard drive and re-load the software.  The manufacturer no longer has parts available for these units.

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WPR broadcasts in HD on many of its stations.  One of the most exciting aspects of this technology is the ability to deliver multiple channels of content on a single FM frequency.  Unfortunately there is a limited amount of digital bandwidth available for the additional channels.  About 96 kbps is available for audio or data.  Initially the only split available was 48 kbps for the main channel with the remaining 48 kbps available for additional channels.  Recent software verisons have allowed the main channel to drop to 32 kbps, thus allowing an even 32 kbps split for three channels of audio.  WPR has been broadcasting 48/48 for the main and a classical music channel but we wanted to look at adding our jazz channel as a 3rd HD service.  We needed to determine, however, whether or not the reduction in bitrate would significantly affect the audio quality.  I went to Casper to make some test recordings over the air.

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