Posts Tagged ‘exciter’

Step Forward, Then Back

Another week has gone by and wouldn’t you know it, that exciter of last week made me take a step back.  That Superciter was working just dandy on the bench when I shut down on Friday of last.  I had it up to 30 watts running happy as a clam (wherever that phrase came from) into a load.  All afternoon it ran until I pulled the plug for the weekend.  Come Monday of this week, Mr. Murphy struck.

As usual with these things, I felt I should run another bench test before calling this exciter good.  Plugged it in and let it run.  It started out just fine at 30 watts.  I’m happy that nothing changed while it sat doing nothing for a weekend.  We all need time off.  I wander through the shop while doing other things.  I walk right by the bench late morning and stop.  Take a couple steps back and look at the forward power.  16 watts!  Huh?  Fan is working and I pop the top open.  Not heat.  Shoot, it’s even sitting under an air conditioning vent.  Time to pull it apart and take the test point readings.  I start to see a couple of anomalies, though for the most part all readings were good.

I sit down with the schematic and refresh my brains on the previous week pointers on what drives what and who and where.  Take a couple more readings as I watch the power drop down below 10 watts.  Something is failing and failing slowly.  No faults, just no power.  OK, if those don’t get enough drive what happens?  I’m starting to get the feeling there is a drive issue.  Why it didn’t show last week is interesting.  I have a brief email exchange with GatesAir.  I describe the situation and how it changed from last week.  The same conclusion that something is not giving enough drive.  We are going t concentrate on the RF drive produced by the FM Synthesizer board.  I have a couple of parts ordered, so we wait until they arrive.  Let’s see if this takes care of it.

In the meantime, we had our annual fire inspection.  Meetings.  A last minute invite to Al Salci’s (of SAS fame) presentation of AVB (Audio Video Bridging) was a highlight.  Great presentation if you get a chance to witness it.  At least I had time off from wrestling with that exciter!  Every week is a learning experience, so take advantage when you can.  Next week more meets and greets.  Let’s see what I learn and maybe even get an exciter repaired.


Categories: Equipment, Management Tags: , , ,

Harris Flexstar

January 29, 2009 Leave a comment

And on the other side, we had to do some network modifications while we installed the HD for the Nautels and other two stations. The bottom line is we had to configure our switches to a managed mode and take down the HD data streams to do this. The Nautel gear came back without much issue when all was done. The Flexstar did not fair as well. As it was late in the day we decided to let the HD slide until today.

What did we find: This morning I was told to listen closely to the station. I confirmed an audible tone in the audio. Before heading to the site, I confirmed that the HD stream did not recover on its own. I was able to ping the exciter. Questions popped into my head. I can ping the box, so network connectivity was good, but no stream. Interesting. Once at the site I noticed the red LED on the Flexstar indicating that something was not right with the data. We switched to the backup transmitter and confirmed the tone went away. It did. The Flexstar had degraded to the point it was generating some sort of intermodulation tone.

I rebooted the Flexstar by cycling the power. After boot, it came up and all looked good. After placing it back on the air, the tone was gone and the analog audio was good again. Very interesting. As you may guess, I am going to send a note to Harris regarding this.

Categories: Equipment Tags: , ,

Nautel vs. Harris

January 16, 2009 Leave a comment

I really do not want to get into such a “fight”, but our IT guy and my assistant mentioned how much better our Class A simulcast sounds compared to our Class B main station. This morning we took a trip to a spot where both stations come in real well, analog and HD. We listened to one. We changed to the other. Very interesting results.

The Class A station runs the Nautel V1-D with the M50 exciter and the Class B station runs a Harris HTHD+ with a Flexstar exciter. Both have the same processing. Both are fed the same way. The only difference is the transmitters. The Nautel does NOT color the audio in any way and the station sounds really good. The Harris colors the audio, it is slightly grungy, and it seems to be lacking in fullness and apparently “missing” sounds. It is quite interesting. We intend to record our results when time permits and everything settles down on the other work.

Anyone have similar experiences? Oh, we also noticed the HD’s sound different too. To us the Nautel is more listenable than the Harris. Crazy. An exciter and transmitter should not color the audio or degrade the audio in any way, shape, or form.

Categories: Equipment Tags: , , , , ,
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