STL setup

Gotta watch those Fresnel zones!
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kell_vern
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STL setup

Post by kell_vern » Fri Jun 17, 2016 8:35 am

good day Engineers..., need help here..
our station needs a new STL setup, our contractor ask me this and i had little idea regarding
STL technicalities. He ask me this,
Please ask your people what system do they want to use out of the following 3 selections
1. Monaraul systems with antennas
2.SCPC Stereo systems with antennas
3. Composite Stereo systems with antennas

i need your inputs regarding this...
what can you recommend? or best setup...
we'll gonna use the new setup for a 4km distance, from studio to the mountains..

our current setup (buildings apart - 200m), we're using an audio processor (omnia 6EX) >>RVR STL PTRL-NV >>> RVR STL RCV >> GATES DIGIT CD exciter>> Transmitter

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Deep Thought
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Re: STL setup

Post by Deep Thought » Fri Jun 17, 2016 8:55 am

#3 is what you have now. #2 is usually called "dual mono" or discrete stereo (one channel per transmitter/receiver pair) so I'm not quite sure what they are thinking the difference between 1 and 2 are.

For such a short hop I'd just use what you have now unless you need IP connectivity at the transmitter site. If so, then it gets a bit more interesting.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

TPT
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Re: STL setup

Post by TPT » Fri Jun 17, 2016 2:27 pm

I would concur. --but why the questions? are you changing studio or transmitter sites?

Generally, if you can see your transmitter site (or if you could see it if you were up as high as the STL antenna) the present system would be the most reliable link. And since you already have a stereo composite system, I am assuming you are programming an FM with stereo programming, or have in the past.

Now, if you were programming an AM station, then the mono STL would make sense. A single channel per carrier STL system--also called a discrete stereo system--has lots of disadvantages and only main advantage--the single channel STL systems work much better on really long paths. Like 40 KM, not 4 km. The disadvantges are that you have to move your processing to the transmitter site, and it gets complicated to feed a RDS generator.

As to IP connectivity--there are other ways to do that without disturbing your main program STL. Such as the unlicensed 5 ghz. systems (which may or may not be legal were you are).

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Shane
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Re: STL setup

Post by Shane » Fri Jun 17, 2016 2:40 pm

Looked to me like the OP is changing TX sites from 200m away to 4km away. I agree the present arrangement seems best. Question: is the site 200m away going to remain as a backup? If so I'd put up a new antenna for the new path, connect it and the old STL Tx to a coaxial switch for use when feeding the old Tx site.

On the other hand, there might be enough signal coming off the side of the studio side antenna to also put a usable signal on the Aux without an extra antenna.

And if the two sites are on more or less the same azimuth from the studio end, then the last paragraph goes without saying.
Mike Shane, CBRE
---Omaha---

kell_vern
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Re: STL setup

Post by kell_vern » Fri Jun 17, 2016 6:54 pm

thank you @Deep Thought , @TPT , @Shane
are you changing studio or transmitter sites?
we're both changing the tx site and studio. I forgot to mention, we're operating an FM station.
Question: is the site 200m away going to remain as a backup?
no, new setup will be 4km away.

again thanks.. :D

RodeoJack
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Re: STL setup

Post by RodeoJack » Fri Jun 17, 2016 7:04 pm

I understand this may not apply here, but I don't see the ongoing resistance to having processing at the transmitter. Now that most modern processors can be accessed online, if it suits your purpose, what's the problem? In the Seattle market, I know of several stations that do this as a matter of practice, from PC-based software processors up to the latest Optimod and Omnia models.

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Shane
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Re: STL setup

Post by Shane » Fri Jun 17, 2016 10:02 pm

We're thinking he doesn't have internet at the tx site.
Mike Shane, CBRE
---Omaha---

TPT
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Re: STL setup

Post by TPT » Sat Jun 18, 2016 6:56 am

Also, if you are using RDS, much more convenient to have the RDS generator and processor at the studio for the data feed.

kell_vern
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Re: STL setup

Post by kell_vern » Sun Jun 26, 2016 5:21 pm

good day ALL,
what can you say with this STL setup
Marti - STL-20C; Scala 5 element yagi antenna (CA5-300) ?

TPT
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Re: STL setup

Post by TPT » Mon Jun 27, 2016 11:00 am

Should work, if your regulatory folks approve. Depends on how crowded the STL band is in your area, though. Here in the states, FCC likes to see highly directional systems, typically a minimum system would use a Scala PR-950 or similar antenna on both ends; but even in smaller markets it is not uncommon to have a dozen or so STL systems operating. If you have terrain where there is one big hill where all the FM's congregate, you should definitely plan on using a highly directional receive antenna so that you don't receive interference from other STL hops.

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