6-Jul-2009 Important changes to the FCC database

Now that the June 12 deadline is over, the FCC has begun processing applications for low power digital transmitters (Class A, translators, boosters, etc.).  However, this time around, the FCC has started filing these records in a somewhat unusual way (at least compared to how they've been done in the past).  Some of these recent additions have the exact same callsign and facility ID as other records in the database even though they appear to be completely independent transmitter facilities (different location, different transmitter specs, and different channel assignment).

Ordinarily, the same facility ID is used to track the primary transmitters of a specific broadcaster (e.g., KCBS analog and digital transmitters had the same facility ID).  Translators and boosters were typically filed under unique callsigns and given their own facility IDs.  This is no longer the case, and it looks like we are going to have a new rule for digital translators/booster going forward.

Now it appears that primary and secondary transmitters are going to be filed under identical callsigns and facility IDs, with the only difference being a new database field called the "site number".  For the records filed so far, it looks like site number 0 typically refers to the primary site, while numbers 1 and higher are used for the other transmitters.

Interestingly enough, it appears as though this new field is not visible on the FCC's own TV Query pages .  For example, WNYT is a station that has some of these new records filed for it.  An FCC search for this station gives you multiple records on different channels (12, 18, and 45).  The main broadcast is actually on channel 12.  The other records are NOT updates to the channel 12 record, but are instead separate new facilites (translators) at other locations.  Despite all our digging around the FCC results, we were never able to find an indiciation of the site number on any of their displays.

The data is available in the raw database files, but this detail is not made readily apparent via the FCC's lookup tools.

We've enhanced our database handling to deal with these new types of records, but this may lead to some interesting looking results.  Since it's now possible to have the same callsign on multiple transmitters, you may see the same callsign listed more than once in the signal analysis results.  This is potentially confusing because some people might be within range of more than one of these transmitters and can in fact receive the same channel from multiple sources.

Our report output will probably need to be enhanced to make records having the same callsign distinct from one another.  For now, we'll just need to deal with the fact that some callsigns will appear multiple times in the reports because they represent different transmitters with the same label.

Also keep in mind that these records were filed very recently.  This means that most of them are probably not operational yet.  We're including them in our reports for now so that people can plan for them, but it is unknown if or when any of them will actually begin regular operation.

Our expectation is that many more of these records will start to appear over the coming months.  Most will be translator and booster stations at first, but we are also expecting more applications for Distributed Transmission (DTx) systems to appear.  DTx installations will cover an area by setting up multiple transmitters on the same channel to fill in all the coverage holes.  Instead of daisy-chaining transmitters (as with translators and boosters), all DTx transmitters operate synchronously as if they were a single mega-transmitter.  There is a fundamental difference in operation of DTx networks, and they have the added benefit of occupying fewer distinct RF channels in their area of coverage.

We want our tools to help locate the best transmitters to use no matter what type they are, so you can expect even more changes over time.  The changes we're starting to see in the FCC data is just the beginning of many important changes to come.  Stay tuned for more.

 
 
 
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