STL

Everything technical about radio can be discussed here, whether it's transmitting or receiving. Guides, charts, diagrams, etc. are all welcome.
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Intruder
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STL

Post by Intruder » Sun Jan 11, 2015 12:57 pm

Being guys in the know.

Was wondering on STL,I know people have used Band 1, band 3 and 10ghz links but on my travels I notice community radio stations using other yagi and dish antennas and assume these are the studio links UHF/SHF

What frequencies are they using ?

800mhz / 2.4ghz are they using licence free links ?

Has anyone got any web links to licence free STL equipment ?

Just be interested to know what's out there

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teckniqs
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Re: STL

Post by teckniqs » Sun Jan 11, 2015 4:37 pm

A couple of Manchester community stations use them, they look like 2.4GHz going by the size.

pjeva
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Post by pjeva » Mon Jan 12, 2015 1:11 am

STL frequency for many countries is about 1500 MHz. These are very reliable, long distance, and interference free. 2.4 GHz is mostly forbiden for commercial use.

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Maximus
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Re: STL

Post by Maximus » Thu Jan 29, 2015 1:08 pm

Slightly O/T but this gent used to be a member of the the old forum. He did some great experiments. Delving into sending standard S/PDIF through 2.4 & 5.8 GHz AV transmitters over a long distance.

I hope he joins again, as a clear link for 850m using a set of 25 squid 10mw links is pretty decent.






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Maximus
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Re:

Post by Maximus » Thu Jan 29, 2015 1:12 pm

pjeva wrote:STL frequency for many countries is about 1500 MHz. These are very reliable, long distance, and interference free. 2.4 GHz is mostly forbiden for commercial use.
I acquired a few 2.4GHz stereo audio links from Arqiva. They looked pretty old but were definitely used for STL. Only low powered 1U sized units TBF, but definitely travelled with the correct antennas, which are peanuts in the computer shops here.

Got a nice 5W 24db wifi link for just over a tenna. When I'm on the roof I can pick up wifi from literally miles away :D

Gum
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Re: STL

Post by Gum » Thu Jan 29, 2015 10:00 pm

Maximus wrote:Slightly O/T but this gent used to be a member of the the old forum. He did some great experiments. Delving into sending standard S/PDIF through 2.4 & 5.8 GHz AV transmitters over a long distance.

I hope he joins again, as a clear link for 850m using a set of 25 squid 10mw links is pretty decent
Me too! That's some interesting stuff - had never thought of that...

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teckniqs
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Re: STL

Post by teckniqs » Thu Jan 29, 2015 10:06 pm

If 10mW can achieve those kind of distances I can't imagine what 5000mW will do and I'll be very interested to find out.

Gum
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Re: STL

Post by Gum » Thu Jan 29, 2015 10:38 pm

Yeah and I guess there is nothing to stop you daisy chaining a couple...

PC running to a stock sender in a flat down below with the receiver up on the roof, patched into another sender attached to a very directional aerial. There are two bands to play with as well. :)

NOYB
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Re: STL

Post by NOYB » Fri Jan 30, 2015 11:11 pm

If you have direct, unobstructed line of sight, then 5.8ghz wifi is the way to go. Don't bother with analogue AV stuff! The IR2007 compliant units can do extra power upto 4w eirp and distances of 30km or more are claimed. Over shorter distances it's really easy to get huge bandwidth which means you can run uncompressed PCM audio (=perfect quality) if you want instead of mp3 or aac. Try Solwise.co.uk - really cheap. Then you need something to stream the audio over this digital link. Barix instreamers and exstreamers are ideal, but pricey. Old PC's with freeware or maybe old smartphones are another way of achieving this.

Gum
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Re: STL

Post by Gum » Sat Jan 31, 2015 4:25 pm

It's not analogue though, I think he is just using the video channel bandwidth to transport a digital PCM stream over S/PDIF. If I understood what he was doing right, it is incredibly simple really but also very clever.

In theory, you should be able to use something like this with only a receiver unit and a cheap DAC like this required at the far end.

Minimal hardware and power required on both sides of the link. :tup

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Re: STL

Post by NOYB » Sun Feb 01, 2015 10:29 am

Fair enough Gum - I guess it depends how cheap you want to go. Personally for reliability and other reasons I'd rather use the kit I suggested - nice and neat, plug and play and they have 15db antennas built-in so will go a lot further than omnis

Gum
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Re: STL

Post by Gum » Sun Feb 01, 2015 3:55 pm

Yeah, ideally I'd rather have a nice fat TCP/IP pipe and plenty of processing power too - lots of benefits, error correction built in etc.

If you need to minimise power consumption or equipment left on site though, this is pretty interesting stuff!

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