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Howdy!
During my last travel, I took my MPX tuner and laptop with me, and recorded lots of stations in:
Cleveland, OH
Lancaster, PA
Gothenburg, Sweden
Stockholm, SwedenThe recordings can be downloaded from:
http://mpxtool.com/site/airchecks.html
Enjoy! 🙂
And, I’m looking forward to recordings from YOUR city. (Hint, hint)
Best,
///LeifWhat is required to do such a recording? Is it more than just recording straight from FM radio?(maybe even tapping into the radio’s circuit to get a line-out of the audio unchanged?)
Hi LPY!
Indeed, you have to tap into the radio to get the MPX Composite signal before stereo decoding / filtering / de-emphasis, and then record it with a 192 kHz sound card.
Check the Tivoli Model One thread below for instructions on how to do this with the Tivoli Model One. 🙂
Best,
///LeifCool. I don’t have a Tivoli though, but I think I’ve found the output..maybe, because there’s a sharp cutoff at around 25KHz.
edit: I think the soundcard must be limited to 48khz recording.. Is there a way to check if it’s 48k and not 192k?Easiest is to check the specs.
Some sound cards have a control panel where you can choose the sampling rate. If it does, and 192000hz is not one of the choices, then chances are it doesn’t support it.
If it has no control panel, you can try to record at 192000hz with for example adobe audition, and then check if there’s a cutoff at 24 or 48. If there is, 192k is not supported.
What card are you using exactly?
///Leif
This computer’s old..SoundMax Intergrated Digital is what the driver says. Seems to playback 192k fine, but not record that high.
The laptop’s max setting however is 96k, which sucks too. Although, I can see the full 48k of audio on that one, so I’m pretty sure I found the mpx output. It’s weird that it only offers 96k and not 192k for recording, it’s fairly new. The driver for that one says Conexant High Definition Audio.
Looks like I need a new soundcard that can record it 🙂
Is it possible to record a HD station’s MPX and get the HD signal?
Why I ask, I don’t live in US and can’t listen to HD-Radio, but I got me an HD-Radio on eBay. So maybe If I rebroadcast an MPX recording from a HD station with a small FM transmitter then I could test my HD-Radio 😀
If it’s possible, please record any HD station for me.
/Ken
Hi Ken!
It’s not possible. HD radio is not actually a subcarrier of FM, but are actually separate carriers, next to the main carrier!
Then again, I’ve heard that there are FM rebroadcasting receivers (like the fanfare) that are wideband and accurate enough to capture the HD carriers as well. If so, it’d be possible to record it, but you’d need a lot higher sampling rate than 192, which is as high as any sound card i’ve ever seen goes.
///Leif
[quote author=”Leif”]Hi Ken!
It’s not possible. HD radio is not actually a subcarrier of FM, but are actually separate carriers, next to the main carrier!
[/quote]
Thanks Leif, so no fun with my HD-Radio then 🙁 I have googled several times for a software HD encoder but not found any, and as HD is not an open standard I asume that I will not find any. So I have to wait until DRM+ receiver hit the market as I can do DRM+ with the Spark encoder.
Indeed. It’s a proprietary technology, with yearly licensing due to ibiquity, but the worst part is — it’s AWFUL. It sounds truly horrendous. You’re not missing much.
In my humble opinion, if they had used aacPlus, it would have been worth something. However, they didn’t — due to political reasons (i.e. Lucent wanting a piece of the pie) they’re using the PAC codec. When they later realized that there was just no way to make it sound acceptable at the low data rates HD radio provides, they licensed just the SBR portion from aacPlus. So, now you get PAC artifacts doubled in TWO places in the spectrum. Woohoo!
///Leif
[quote author=”Leif”]Indeed. It’s a proprietary technology, with yearly licensing due to ibiquity, but the worst part is — it’s AWFUL. It sounds truly horrendous. You’re not missing much.
[/quote]That is what I read, that HD don’t sound good. But the "HD people" are good lobbist and salesperons think thats why that way HD is used, and mostly it’s a "US technology", we did it 😉 .
more offtopic…
I did some test at home with a small DRM transmitter om AM, it don’t sound as good as FM, but having in mind that it’s infact AM and uses 20kHz bandwith, then it’s pretty good compare to regular AM. But not that good for a pure music station. Now I used a freeware version of Spark modulator (also tesed Dream) so I don’t have the "real" AAC codec and not stereo mode.
Can’t wait for our goverment in Sweden anounce the DAB+ licenses, I’m on…
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