STL antenna move

Gotta watch those Fresnel zones!
Post Reply
grich
Posts: 297
Joined: Fri Sep 02, 2011 11:19 am
Location: MP89.5, Mason City Subdivision

STL antenna move

Post by grich » Thu May 05, 2016 10:47 am

Have a client moving into a new building soon. The new building is next to the old, and the STL antenna is going to relocate about 90' east of the current location. The azimuth change is around 0.3 degrees according to Google Earth. If I can verify the distance change is less than 1 second of lat, that should make it a minor change (if I understand Section 1.929(d) correctly). The question is, does a minor change of this type require frequency coordination?

TPT
Posts: 622
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: STL antenna move

Post by TPT » Thu May 05, 2016 5:19 pm

Ninety feet & a .2 degree change in direction? If the path direction isn't really changing & the transmit location is essentially the same as before, I wouldn't think this would need the full coordination process.

Heck, a stiff wind might change the main beam .3 degrees at a lot of sites.

grich
Posts: 297
Joined: Fri Sep 02, 2011 11:19 am
Location: MP89.5, Mason City Subdivision

Re: STL antenna move

Post by grich » Thu May 05, 2016 9:13 pm

TPT wrote:...Heck, a stiff wind might change the main beam .3 degrees at a lot of sites.
LOL...I think the existing antenna has the shakes that bad! Ten foot mast on a 20' stub of a 60-year old power pole...a little bit weather-checked!

Radio Ranger
Posts: 74
Joined: Sun May 02, 2010 7:44 am

Re: STL antenna move

Post by Radio Ranger » Fri May 06, 2016 11:15 am

If it's the site I'm familiar with, Greg, then the transmit antenna is a Scala miniflector, correct? The half power beam width on those little guys is huge, anyway.

Steve Brown
Radio Rangers
Minneapolis

User avatar
Shane
Posts: 716
Joined: Fri Feb 01, 2008 12:08 am
Location: Omaha
Contact:

Re: STL antenna move

Post by Shane » Fri May 06, 2016 2:19 pm

It wouldn't cost much to have a surveyor certify that for you. You're going 90 feet east but you want to verify the latitude is less than one second, right? What about the longitude?
Mike Shane, CBRE
---Omaha---

w4cl
Posts: 477
Joined: Wed Apr 09, 2008 3:04 pm
Location: 1 3/4 meters

Re: STL antenna move

Post by w4cl » Tue May 10, 2016 9:27 am

I have 2 RECEIVE sites (one a main and one a backup) receiving the SAME ONE TRANSMITTER, on the same channel, shooting to the same property, just two towers 600 ft apart and they made me license BOTH "paths" of the same transmitter. So I have ONE transmitter with ONE ANTENNA with ONE PATH with TWO call signs going to the same property, same angle, same everything other than the receivers are physically on two different towers 600 ft apart. I couldn't believe it. I was told this was to be sure someone couldn't pop up a transmitter and interfere with one receive site or the other. Tried to tell them if one site got interference, the other one would as well since they are only 600 ft apart LOOKING AT THE SAME DAMN ANGLE!! HELLO!!??

You just can't make this stuff up.

grich
Posts: 297
Joined: Fri Sep 02, 2011 11:19 am
Location: MP89.5, Mason City Subdivision

Re: STL antenna move

Post by grich » Tue May 10, 2016 1:30 pm

Radio Ranger wrote:If it's the site I'm familiar with, Greg, then the transmit antenna is a Scala miniflector, correct? The half power beam width on those little guys is huge, anyway.

Steve Brown
Radio Rangers
Minneapolis
Yep...new antenna is the same thing.
Shane wrote:It wouldn't cost much to have a surveyor certify that for you. You're going 90 feet east but you want to verify the latitude is less than one second, right? What about the longitude?
I did a quick check with my Garmin Dakota 20 and it's looking to be definitely more than 90. Gonna be just over one second. Looks like we're coordinating. Still going to have the surveyor visit to get it right. Longitude should have been dead east (no change).

TPT
Posts: 622
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: STL antenna move

Post by TPT » Tue May 10, 2016 3:20 pm

Whoa! Look a section 1.929 and 1.947:

In 1.929:--a major change for an aural stl is described as---
(i) Any change in transmit antenna location by more than 5 seconds in latitude or longitude for fixed point-to-point facilities (e.g., a 5 second change in latitude, longitude, or both would be minor); any change in coordinates of the center of operation or increase in radius of a circular area of operation, or any expansion in any direction in the latitude or longitude limits of a rectangular area of operation, or any change in any other kind of area operation;

(ii) Any increase in frequency tolerance;

(iii) Any increase in bandwidth;

(iv) Any change in emission type;

(v) Any increase in EIRP greater than 3 dB;

(vi) Any increase in transmit antenna height (above mean sea level) more than 3 meters, except as specified in paragraph (d)(3) of this section;

(vii) Any increase in transmit antenna beamwidth, except as specified in paragraph (d)(3) of this section;

(viii) Any change in transmit antenna polarization;

(ix) Any change in transmit antenna azimuth greater than 1 degree, except as specified in paragraph (d)(3) of this section ; or,...

Under 1.947, major changes require an application, minor changes do not.

So, since the change in location is less than or maybe about 1 second, and the azimuth, emission type and EIRP will remain the same, an application is not needed, so coordination is not needed.

As a practical matter, the purpose of coordination is to ensure that you don't wipe out someone path--which could happen, for example, if you are shooting east to the transmitter from the studio--then change studio locations and shoot west. There's just not enough difference between old and new path here to create any interference problem that wasn't already in place.

grich
Posts: 297
Joined: Fri Sep 02, 2011 11:19 am
Location: MP89.5, Mason City Subdivision

Re: STL antenna move

Post by grich » Tue May 10, 2016 5:02 pm

I thought the rule said 1 second, not five.

I'll need those new glasses after all. :D

Thanks for the dope-slap!

User avatar
Deep Thought
Posts: 3149
Joined: Thu Mar 20, 2008 9:23 am
Location: La Grange, IL
Contact:

Re: STL antenna move

Post by Deep Thought » Wed May 11, 2016 12:36 pm

I can pretty much guarantee that the 601 will kick back at 1 second without prior coordination.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

TPT
Posts: 622
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: STL antenna move

Post by TPT » Wed May 11, 2016 4:16 pm

Which means waste about $450 or just move and not worry about it. Many installations have greater error in their coordinates (from errors in the initial application) than the 90 ft. move will have here.

As a practical matter, the general public happiness of other users of the band would be better served by replacing the miniflector....

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest