Optimod

Engineer's Corner
8:02 pm
Sun November 23, 2014

TheEC: "Whistling" While the (88.1FM Transmitter) Works

An Orban Optimod 8100A audio processor.
Credit Gearslutz.com

UPDATE DEC.1, 2014: our demo unit of the BW Broadcast DSPXmini-FM SE audio processor arrived today.   It's been installed on 88.1FM and initial tweaking is complete.  The sound seems markedly improved.  I'll be fiddling with it further to adjust it across different programs.

ORIGINAL ARTICLE: About a week ago, your intrepid engineer made some changes to the airchain on our 88.1FM that should've, in theory, been wholly beneficial and with no potential for downside.  However, around that same time I started getting reports of an odd whistle...or just high-pitched static...that would come and go with no apparently rhyme or reason.

These reports aren't widespread, but there's been enough that I'm no longer inclined to think it's just an odd run of people happening to have poor reception.   The only commonality is that it seems to occur only when reception of 88.1 isn't very good to begin with.  Not necessarily "poor" reception at all, just not "super-solid".

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Engineer's Corner
10:17 am
Thu May 22, 2014

TheEC: Air Conditioning at 88.1FM

New portable A/C. Note the pink foam insulation along the walls.
Credit Aaron Read RIPR

Regular readers of the ENGINEER'S CORNER might recall my story about air conditioning at our 102.7FM transmitter in Narragansett Pier.   Well now I'm pleased to report that we have air conditioning at 88.1FM WELH in Seekonk as well!

In many ways, this is an even bigger deal; 102.7 had a hefty vent fan system that could move a lot of air.  Sure, if the air outside was hot, it means the air inside was hot, too.  Usually you can't cool a room using outside air below about +10F degrees above outside air temps.   So if it's 90F outside, it's 100 to 105F inside...ugh!  

And at 88.1, we didn't really have even that.  The transmitter site is an 8x10ft shed with a single 12 inch desk fan blowing air out one of the wall vents, and no insulation whatsoever on the walls or ceiling.  Temps routinely broke 120F inside, even when it was only 70 to 80F outside.

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Engineer's Corner
10:08 pm
Mon January 27, 2014

TheEC: 88.1 Studio/Transmitter Link

Screenshot of the Comrex BRIC Link web GUI
Credit Aaron Read

In light of ongoing issues with the Studio/Transmitter Link (STL) for WELH 88.1, we have implemented a new STL  schema.   If you heard a lot of odd audio dropouts on 88.1 today, that was the reason.

The good news is that we should have a pretty good temporary solution in place, and a solid path for a permanent solution is on the horizon (tentatively scheduled for mid-March).   Best of all, I was able to put in a new(er) Orban Optimod 8100A audio processor to replace the less-capable Inovonics DAVID-III.  There's a little sibilance still, so I need to tweak the settings.  But overall the sound should be much louder, fuller, and more consistent.

Read on for more details...

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