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? Curt Scott Fybush wrote: At 02:38 PM 12/23/2005, you wrote:Since it wasn't obvious, I checked to see what was unique about the KAVT test and quickly saw it was running day power at night. That made sense as a good DX test, but something else I came across did not. KAVT is listed on Radio-Locator as: * Antenna Mode Non-Directional - 2 Patterns * Right away I had to ask, how can a non-directional antenna have two patterns. So I went to the FCC database and found there was only a single tower, further adding to my confusion, but got a slightly different listing: * ND2 - Non-directional Antenna: Different constants day and night * Since I have no idea what that means, it is easier to accept. It would be nice, though, to actually understand it. Would anyone care to take on the task of trying to explain this to me?It's my understanding that the way the CDBS database is now set up, it pretty much has to have separate records for day and night operation for each AM station - and if anything at all is different between day and night (in this case, 10 kW day vs. 1 kW night), it absolutely will have two records. There are still a lot of "ND1" records in the database, because it's not automatically updated to reflect the new standards unless a station applies for a change of some sort. Look, for instance, at KOZI 1230 in Chelan WA - it was in the database as "ND1," but has filed a minor application to correct its coordinates. There's no actual change in the station's operation, but when the application is processed, KOZI will become "ND2" in the database. s |
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