FreeDAB

A place to discuss the latest on the airwaves across Ireland, history & everything in-between

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NDLS
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FreeDAB

Post by NDLS » Sun Sep 08, 2019 7:06 pm

I'm surprised there is no discussion here of the DAB pirates here in Ireland. It started in Cork with the a couple of months ago, and a relay of it is now on in Dublin. Carrying mostly dance pirates but there is a country station, an easy listening one and a classic rock also. using 5B running a few 100 watts in Cork, Dublin is lower power as they are still testing. Interesting development though Google 'FreeDAB'

drumandbasshead010
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Re: FreeDAB

Post by drumandbasshead010 » Sun Sep 08, 2019 7:15 pm

Picked it up yesterday in Cork, 10 stations on it. Very suffisticated.

Albert H
proppa neck!
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Re: FreeDAB

Post by Albert H » Tue Sep 10, 2019 12:47 am

Excellent! The CBC (Canadian Broadcasting Chappies) has developed some Open Source DAB solutions, and the hardware is relatively simple and cheap. I have had my own 100mW DAB multiplex "broadcasting" to my neighbourhood, with half-a-dozen Raspberry Pi SBCs as internet "receivers" for the stations that I want to put on DAB for the last three years. It's based on the Hack RF One and a modulator board sold by an engineer from Switzerland. It's a complete lash-up, and lives in a desk drawer! The aerial is a quarter-wave vertical with groundplane (outdoors), and the useable range is about ¾km.
"Why is my rig humming?"
"Because it doesn't know the words!"
;)

NDLS
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Re: FreeDAB

Post by NDLS » Thu Sep 12, 2019 7:52 pm

Only problem with the HackRF one I'm told is the 'shoulders' are a bit wide, i.e. its not that linear. Fine for very low power but you wouldn't want to feed it into an amp, so I am told by one who tried! The boards available from Sergiy in Ukraine are clean though, apparently. http://wiki.opendigitalradio.org/DAB_hardware. I experimented with ths CRC MMB-DAB DAB using a USRP1 back in 2009, and it was also clean. We used MMB-DAB for the Total Broadcast DAB trial from 2010 - 2014 in Ireland, putting in a lot of interactitive work with the Canadians to get it stable

Albert H
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Re: FreeDAB

Post by Albert H » Fri Sep 13, 2019 10:57 am

Funnily enough, I'm waiting for one of Sergiy's boards at the moment!

The Hack RF One solution is OK to amplify, but needs a fairly tight roofing filter to clean up the shape of the transmission. Just for amusement, I knocked up a little Band III linear amplifier that did about a Watt when driven by a filtered Hack RF One. My little DAB "bouquet" could be heard over most of the town!
"Why is my rig humming?"
"Because it doesn't know the words!"
;)

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