STL antenna

Gotta watch those Fresnel zones!
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kell_vern
Posts: 20
Joined: Thu Dec 06, 2012 6:24 am

STL antenna

Post by kell_vern » Wed Sep 07, 2016 5:50 am

good day engineers, i'd like to know if is it OK to put an STL antenna near telco antennas..
does it cause interference or any problems? what should be the proper setup with this?
because it is the highest side in the building. thanks.... (see pic below of the actual location)
Image

TPT
Posts: 604
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: STL antenna

Post by TPT » Wed Sep 07, 2016 6:25 am

Well, I would be very cautious working around the cell antennas because of RF exposure. Also, I would wonder if the cell folks have some kind of exclusive arrangement with the building owner.

Other than that--assuming you don't stick your dish in front of someone else's dish--the frequencies in use are different & there shouldn't be any interference.

kell_vern
Posts: 20
Joined: Thu Dec 06, 2012 6:24 am

Re: STL antenna

Post by kell_vern » Wed Sep 07, 2016 6:33 am

based on the pic, where would be the best location of my stl antenna? can i put it near the dish?
my STL freq is 313.5 Mhz.. i already talk with the bldg engr regarding telco antennas if it had exclusive rights of the place but he don't have clear answer yet because he's new in the bldg.

BigRed
Posts: 79
Joined: Tue Mar 27, 2012 8:59 am

Re: STL antenna

Post by BigRed » Wed Sep 07, 2016 10:28 am

Need a tad more information to even venture a guess . . .

1st, "STL" (Studio-Transmitter Link) implies point-to-point communications with a directional antenna like the ones shown in your photo. What direction will the antenna be pointing?
2nd, 313.5 mHz is a rather low frequency for an STL,, at least in the States (are you in the States?). [We do have, or used to have a TSL band (Transmitter-Studio-Link) down in the 500-mHz range as I remember.] That's a pretty low frequency for a parabolic reflector (although quite possible). Chances are you will be using a log-periodic antenna or a yagi, something like is available from Kathrein Scala (log- periodic's and yagi's are pretty much the same animal from a physical viewpoint)?
3rd, is there any vacant space around that parapet that isn't shown in the photo? With a log-periodic or yagi a simple vertical pipe should suffice. If you can't find space to install a vertical support of your own you can always extend one of the existing vertical pipes a bit to create a space for your antenna, so long as you secure permission from the owner of the existing vertical and doing so doesn't violate any rules or laws. You will also have to maintain appropriate distances from neighboring antennas. (That depends on the antenna types and operating frequencies.)
4th, as a courtesy you should check with all of the existing services to see if there's any chance you will cause them interference. (There's software out there that can be a good start for making that assessment.) And remember, if your new installation does cause interference to already existing services you will be obligated to mitigate that (morally, if not also legally), even to the point of shutting down your STL.

Good luck!

W2XJ
Posts: 76
Joined: Mon Dec 03, 2007 12:15 pm

Re: STL antenna

Post by W2XJ » Wed Sep 07, 2016 11:20 am

You didn't say if it was transmit or receive. Receive would not pose a problen. With transmit, however, intermod is always a potential problem. If the cell systems are using LTE, Anything greater than -136 DBm is a problem for them. Since you are last in, regardless of the actual prevailing law, you will likely have to carry remediation costs.

All that said, provided you have a proper agreement with the building owner, put up your own mast right where the ladder is. I am assuming that location has a clear view of the necessary path. I have built 450 MHz STLs and used log periodic antennas or where necessary, arrays of logs. The biggest problem using low frequencies is interference, especially during summer months.

Taking a wild guess based on the gramatic structure of the query and the proposed frequency that the location is South or Central America. Good luck!

TPT
Posts: 604
Joined: Mon Dec 03, 2007 3:18 pm
Location: St. Marys, WV

Re: STL antenna

Post by TPT » Wed Sep 07, 2016 1:42 pm

At 313.500 MHZ--this is an overseas operation, No telling where 4G/LTE operates--if it exists--although they usually worry about 7th/8th harmonics out of the FM band. In the picture I see at least one antenna that looks like a UHF vertical. So best to check on who is using what frequencies.

kell_vern
Posts: 20
Joined: Thu Dec 06, 2012 6:24 am

Re: STL antenna

Post by kell_vern » Wed Sep 07, 2016 6:19 pm

@BigRed,
1. the antenna will pointing on the right side of the pic.
2. i'm from Philippines, and we're using a yagi antenna.
3. the whole area is surrounded already with telco antennas, the only vacant space is with those dish on the left side of the pic.
4. yes, we're contacting these telco folks now for any possible problems...


@W2XJ,
the STL antenna to be used is a transmit antenna. i'm from Philippines :D

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