Re: [IRCA] Upcoming DX Tests (New KAVT Fresno Test!)

[Scott Fybush <scott@xxxxxxxxxx>]

At 06:22 PM 12/23/2005, W. Curt Deegan wrote:
>I appreciate the info on the nomenclature, but what I'm really 
>asking about is the idea that a single tower can  have two patterns, 
>or as the FCC puts it, two constants.  Is this just saying that 
>because there is lower power at night this in itself constitutes a 
>different pattern?
>
>I had in my head that an antenna pattern was the directional shape, 
>not the power contours.  Is that where I'm confused?
>
>Now that I say it to myself I guess that's all an antenna pattern 
>is, the power contours, either in a circle around a single tower, or 
>in some more complicated form involving multiple towers.
>
>Based on this logic then, the only way to have a single pattern 
>would be to have only one power level, whether it involved any 
>directionality or not.  Am I getting close?

Your original understanding of "pattern" is correct. The distinction 
here is between "pattern" as we understand it, and "database record," 
as the FCC now handles things.

Nondirectional is nondirectional, so a station like KAVT has the SAME 
pattern day and night. The only difference is in the way the FCC's 
CDBS database system expects to see an application. It wants both a 
day and a night record, even if they contain the same data.

Older data, from before CDBS was introduced in the late nineties, 
wasn't modified for the system, so there are still plenty of "ND1" 
and "DA1" records in there. But any time any of those stations files 
for any sort of a change, the system wants to see both a day and a 
night record.

Take NYC as an example - of the three former I-A clear channel AMs 
there, two (660 and 880) last applied for any sort of modification 
way back in 1979, so they're listed as 50 kW ND1. But WABC applied 
for a change of some sort in 2000 (something minor, as I recall - 
possibly even just a correction of its coordinates), and so it now 
appears in the FCC database as 50 kW ND2.

There's NO difference, technically, between the "ND1" operation at 
WFAN and WCBS and the "ND2" operation at WABC. It's all just how they 
appear in the FCC records.

(And no, a subsequent correction wouldn't make it an "ND3," thank you 
very much... :-)

Where this has the potential for confusion for DXers is that it 
eliminates the useful distinction between "DA-1" and "DA-2" listings 
in the FCC database itself, since any new application, even if it 
applies for identical day and night operation, still gets filed as a 
"DA2." You now have to actually look at the pattern (on fccinfo.com 
or AMSTNS or whatever database viewer you prefer), or pull out the 
NRC Log or WRTH, and see for yourself whether that "DA2" is actually 
the same pattern day and night, or whether it's different.

(Anything that was listed as "DA1" under the old system, or whatever 
the NRC Log equivalent is - I never did get the hang of those "U3"s 
and all that - would, however, have had to have had the same power 
level day and night. Otherwise, it would have shown up in the FCC 
database with two records even before CDBS required two records for 
everyone. In practice, I can't really think of any stations that 
change power levels, but not pattern, at sunset.)

Again, none of this changes anything in the real world - it's just a 
reflection of how the FCC's database system processes new applications.

s 

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