FreeDAB

[Electronics]

To be honest with you setting up dab is no easy .it costs money to buy the hardware as folk I know use a hackrf for transmit or LimeSDR or easydab .all those things cost I was told .however to set this up is all in the dab config to setup it up I believe .

[rigmo]

how to buld? buy?

[shuffy]

how to buld? buy?

5 or 6 years ago I put up a small DAB+ MUX (in England, i know I'm off topic so I'll keep it brief to answer RIGMO's question). I had acquired a LimeSDR and wanted to see if I could do it. I was using the free open source "ODR-mmbtools" (google it) running under linux, the limeSDR, and some simple RF gear. Forgive me if I'm not 100% on all the detail here, as I was doing this with only one eye open, but it was something like this:

Software (all included in ODR-mmbtools). There is some software config required and I'm pretty sure you have to compile everything yourself.
1. Audio encoder process (one for each programme in your mux). Produces MPEG or AAC streams IIRC
2. Encoded streams are fed into multiplex process, this produces a single stream of so-called "ETI" data.
3. DAB/DAB+ modulator process, this reads the ETI data and generates I/Q data which can directly drive various SDRs.

My MUX had 4 simultaneous programmes on it but these were not live - I encoded up 4 long audio files and created a single huge ETI file from these. When fed to modulator process, I had a MUX of 4 programmes on air. There's configuration needs building with MUX name, station name etc IIRC.

One version of the above I've seen for "live" broadcasting has each station running the encoder process on something like a Raspberry Pi, each one streaming to a single computer running the multiplexer and the DAB modulator - this would typically be something with a bit more grunt, like a desktop. Encoding my huge ETI file was quite computationally intensive and took bloody ages IIRC.

So, apart from the computer hardware, all the above is free.

On the RF side - I was using a limeSDR mini, I think it set me back about £250 at the time. It's not well supported under any operating system IMHO and is a pain in the arse to use. I won't go into detail here. It looks like the prices of commonly available SDRs haven't gone down any since then, so you're looking at £200+ for this part of your chain. There is also the "EasyDAB" which is a purpose built SDR and will cost about the same or more.

With the LimeSDR mini, I was able to generate enough welly to directly drive a 30W Mitsubishi RF amplifier module to approx 7W out. You need to bias them to linear for digital schemes, hence the lower efficiency (the module I used allowed you to bias the PA gate directly so that was easy). This is probably the easiest way to build your driver. The module I used is currently about £50, it was way cheaper at the time!

Antenna - this was a home made 5-element Yagi. I guess if someone made you one, it would probably cost you a couple of hundred (total guess).

With my 7W and my Yagi, at a pretty low site, my MUX was nicely receivable in the car for about a mile and a half in the beam direction. A better site would no doubt have improved things.

So - on top of the computer gear, and homemade antenna, my very small setup cost about £350. The next stage (had apathy not set in) was going to be a larger PA, which you'd need if you wanted any usable range. Let's say you use one of the modern 300W devices like MRFE6VP6300, biased linearly you'd probably get 50 or 60W, which with a decent site would probably get you 5 - 10 miles. This would be another £150 say, plus you'd need filters, power supplies, other sundries etc. So let's say the whole setup excluding computer gear and antenna - £500 to £600. No I'm not offering my services or any guarantees!!!

So, here's the clincher, and I've said this before. I don't believe there's any point in doing this as a pirate, not in the UK anyway. The chances of Joe Bloggs stumbling on a pirate mux with a DAB receiver are minuscule so in order to get listeners, you'll have to publicise what you're doing. As soon as you've done this, your gear's gone and your site's burned. Might be viable if you had several pirates on one MUX all chipping in, but the logistics aren't easy and you'd need someone to keep all these contributors in check. The more I think about this, the more problems there are!

Hope some of that helps. Yes, that was me being brief. Flame me as required