Transmitter Link


We’re currently using an BT Business Analogue circuit to get our audio from the studio to the transmitter site. I think this was often known as a music link or kilostream circuit - it’s fared us very well over the last decade or so.

The reason why I’ve always loved our private circuit is because it’s very reliable, it’s simply just a pair of wires which is then jumper’d to a pair of wires at the TX site - we simply send audio down the wires and out audio pops at the other end.

Now, BT are ceasing these circuits in 2020 (in my experience with BT/Openreach) it will be much later than that but I need to try and find another solution and wondered what our peers are using to send audio to their TX site, I know there are lots of methods and I’d be interested to know which ones you use or might recommend. As with everything Community Radio, costs are important, but so is reliability in this case.

note: we’re not in line of sight so microwave link or similar is not an option.

WCR FM - Wolverhampton

We use IP links (with Fixed IP addresses) where we can’t get a reliable microwave link path - with Sonifex PS-Send and PS-Play codecs.
But don’t forget that VHF (48 or 52 MHz) can work perfectly well over an otherwise obstructed path.
Contact my colleague Phil Furnivall - for more details.

We simply use another low-power FM link on a private frequency, transmitted from our roof, with a receiver at the TX site and another modulator to rebroadcast at our public frequency.

Even more simply (and cheap) we use Icecast and a Raspberry PI. Since our transmission and studio site has very good network we get very small amounts of downtime. We’re talking ISP cutting through cable etc…

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Sorry - what is a “private frequency”?

Sorry, I think I made up a random term there! Just a non-FM broadcast frequency - I think our STL transmits at around 45MHz. Can’t remember the exact frequency off the top of my head!

If it’s a licensed link it will most likely be on 48.3 or 52.75 MHz.

If you’re still looking for advice regarding replacing your Kilostream STL Beaming have been working with a number of radio station to help them to migrate to IP technology. We’re a specialist ISP and have rolled out connectivity to over 700 transmitter sites to date. I’d be happy to offer advice so feel free to get in touch.

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I am surprised at your number of 700. I thought at last count there was only about 700 licensed transmitter sites for radio, both community and commercial. Don’t forget many solutions also exist, such as an excellent STL software solution that I created, in use by many stations around the world and working flawlessly on links that other solutions such as Barix and Deva have failed miserably.

We’ve worked on a number of projects that involve transmitter connectivity, not just in the broadcast sector. You’re of course correct that there are plenty of STL solutions for a radio station to choose from and I’m sure your software does a great job. At the end of the day it’s down to individual stations to find what’s most appropriate to their situation.