How do I find an antenna location if it's not in the DB?

[jjudson]

I'm having trouble getting reception on the 800 Mhz band for the New Jersey State Police. I'd like to put up a yagi and improve my listening. When I look at the database for antenna location information, I get the following message:

There is no FCC license or location information available for this system

Without this info, how can I find out where to aim my yagi for the best results? Can a scanner be used to help tune this? Is there somewhere else I can go for antenna location info?

 

[GTR8000]

Go to the FCC Geo Search, input the coordinates of where you're listening from with a 15 mile radius (start small to get the closest sites, you can always expand the radius if nothing comes up), then do a search on any one of the CC frequencies for the system you're monitoring (North, Central, South). That should bring up the NJSP licenses with the closet site to your location. Also pay attention to the transmitter power output and height. You may find that a site a little further away has a lot more coverage.

License Search - Geographic Search

 

[jjudson]

res6cue_dot_com, that is cool! Thanks!

 

[GTR8000]

No problem.

I believe you're in Gloucester County, right? I ran a 15 mile radius search from the center of Glassboro and came up with two sites, one in Camden County and the other in Salem County. I'm not sure what part of Gloucester you're in, but the Camden site is putting out quite a bit more power at a better elevation, so I'd give that one a shot first. You can use Google Earth to map them out, then use the ruler to draw a line between your coordinates and the tower coordinates, which will give you the heading degrees. You can use that with a compass to help aim the yagi.

 

[APTN]

Antennas

AntennaSearch - Search for Cell Towers, Cell Reception, Hidden Antennas and more.

Enter a town or an address here and you may find the antennas. Just beware, that site searches multiple bands/services so you may get a long list of matches.

 

[jjudson]

No problem.

I believe you're in Gloucester County, right? I ran a 15 mile radius search from the center of Glassboro and came up with two sites, one in Camden County and the other in Salem County. I'm not sure what part of Gloucester you're in, but the Camden site is putting out quite a bit more power at a better elevation, so I'd give that one a shot first. You can use Google Earth to map them out, then use the ruler to draw a line between your coordinates and the tower coordinates, which will give you the heading degrees. You can use that with a compass to help aim the yagi.

res6cue_dot_com, a question:

I looked up several of these sheets and I'm a bit confused. The coordinate settings vary widely from the address. For example, using coordinates, one antenna for the Commodore Barry Bridge is actually all the way down toward Cape May - sorta inconvenient for communications on the bridge itself. The State Police antenna for Berlin actually comes up near Atlantic City using the coordinates. I searched every one of the CCs, and all of them are at crappy distances - with the closest being Malaga, about 18 miles away and heavily obstructed (according to the Hey What's That? website left by Upman).

How should I be sorting this info?

 

[n5ims]

Please note that the license locations in the FCC database (as stated in their comments) is the location where the system is licensed to, not necessarily where the owner is. Often times these licenses are handled by consultants or communications lawyers so a system in Podunk ID may have a license location in Washington DC. This hampers location searches in their database. Once you find the desired system, however, the Locations tab will show the tower location or area that the mobile units are licensed to operate in.

 

[GTR8000]

Don't pay any attention to the addresses using the FCC Geo Search. The only thing that matters are the coordinates for the antenna sites on the Location tab, as n5ims stated.

I just searched 860.9375 (one of the South system's CC's) and license WNDD577 comes up. The Berlin, Camden County site is correctly showing up at 39.804000° (39°48'14.40"N) Lat, -74.932389° (74°55'56.60"W) Long, which is a fairly decent sized tower on what looks like the property of a town/county highway or DPW garage at the intersection of Rt 73 and Zulker Ave. Not sure where you're seeing anything near Atlantic City. The tower is approximately 12 miles from Glassboro at a heading of 53.5 degrees.

ULS License - Public Safety Ntl Plan, 821-824/866-869 MHz, Trunked License - WNDD577 - NEW JERSEY, STATE OF - Locations Summary

39.804000, -74.932389 - Google Maps

 

[jjudson]

I just searched 860.9375 (one of the South system's CC's) and license WNDD577 comes up. The Berlin, Camden County site is correctly showing up at 39.804000° (39°48'14.40"N) Lat, -74.932389° (74°55'56.60"W) Long...

Okay, I'm really confused (or more likely an idiot here). How do you come up with the decimal coordinate numbers. When I entered the data, I interpreted 39°48'14.40"N as 39.481440 and 74°55'56.60"W as 74.555660. This is obviously wrong and explains why I got sent off into the hinterlands.

So the dumb*ss question of the week is: How are coordinate numbers converted to decimals?

Also, while I'm at it, how are the elevations listed? If it says Height w/o Appurtenances 90.0 m, does that mean that the tower is 90.0 meters above sea level, or above the site elevation - which in this case is 47.0 m?

And what is Height w/o Appurtenances anyway?

Okay, my brain hurts. I need to lay down already.

 

[GTR8000]

Convert Latitude / Longitude in Degrees/Minutes/Seconds to/from Decimal (FCC) USA

 

[GTR8000]

Also, while I'm at it, how are the elevations listed? If it says Height w/o Appurtenances 90.0 m, does that mean that the tower is 90.0 meters above sea level, or above the site elevation - which in this case is 47.0 m?

And what is Height w/o Appurtenances anyway?

Okay, my brain hurts. I need to lay down already.

Site Elevation (AMSL) = "above mean sea level" is measured at ground level at the site

Height w/o Appurtenances = The height above ground to the highest point of the supporting structure itself only

Height w/ Appurtenances = The height above ground to the highest point of the supporting structure, including any attachments that may extend higher than the supporting structure itself

HAAT = "height above average terrain" is determined from topographic maps by averaging the elevation AMSL at points along several radials or radii. This is subtracted from the elevation AMSL of the antenna, including both the tower itself and the ground it is on, to determine the difference

Hgt to Tip = Measured from the ground to the tip of the antenna itself


HAAT is generally the most important number, as it gives you an idea of how high the antenna is in relation to the surrounding terrain.

 

[jjudson]

Thank you res6cue_dot_com. Very informative and helpful.