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

[Scott Fybush <scott@xxxxxxxxxx>]

>I've seen a lot (comparatively) of these "correction
>of coordinates" minor apps.
>
>Is this something as simple as people using
>GPS receivers to get a better fix than the old
>quad topo maps provided, or is there something
>else involved with the site itself - perhaps a
>way in which the actual coordinate is defined?
>(site mean center, xmtr location, reference
>tower location, other?)

In many cases, the coordinate correction has come about because the 
tower owner had to register the tower for an ASRN (Antenna Structure 
Registration Number), which has been mandatory for pretty much 
anything above 200 feet for a few years now, and they've found in the 
process that the coordinates that were supplied by the one-eyed 
surveyor who built the site back in 1947 don't quite match what the 
GPS now tells them. (There's the added confusion that the ASRN 
database uses the NAD83 datum, while the FCC is still stuck on NAD27, 
and that can throw things off by a second or two each way as well, 
not to mention making for a royal pain when trying to match ASRN 
numbers to FCC license records at a site with multiple closely-spaced towers!)

In other cases, I suspect the errors are getting noticed when someone 
wants to add something (a cell site, let's say) to the existing tower.

The actual filing is very easy to do and pretty much a rubber stamp, 
and it's better to do it when you notice it than to wait for the FCC 
to come calling later on.

>My estimate of D/M/S* is that the seconds
>are about 101 feet resolution? This could create
>a variation of several digits in the Sec. field in
>both x and y directions for a moderately large site.
>(*based on 69 miles per degree)
>
>What is the attribute of a site that gets described
>by a coordinate?

For a nondirectional AM, it's simply the tower. For an AM DA, it's 
supposed to be the center of radiation in the DA. In practice, that 
seems to usually mean the reference tower in the array; otherwise, 
you could easily imagine an array in which the day and night 
coordinates are slightly different as the station switches pattern.

The only array I know of where that's actually reflected as such in 
the database is WCKY 1530 in Cincinnati, which is a four-tower DA at 
night and which uses only one of those towers by day. There's 
something weird with that whole database record, though, and I 
suspect it goes back to the storm damage about 15 years ago that led 
to the almost complete reconstruction of the site. Only one of the 
current towers is original, and the others were rebuilt in different 
locations. There are old tower piers in places on that property that 
I wouldn't have expected at all, including at least one behind the 
building. (The current array consists of four towers, not quite in 
line, in front of the building.)

s



_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://arizona.hard-core-dx.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx