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73.758

milli-Hertz, huh?! I would think Mega Hertz (MHz) would be HF!


FCC R&R 73.758 states that DRM is authorized for digital HF broadcast service in the USA and has been for awhile.

Many "experts" have spent many pixels whining about DAB and DRM's superiority over IBOC. Yet more whining occurs because there are few IBOC receivers out there and the big, bad FCC won't give DAB and DRM a shot at digital MW and VHF broadcasting.

So anyways, how are all those DRM proponents hearing any DRM signals to compare IBOC if not on shortwave? I would think the market would be flooded with DRM shortwave radios because the FCC settled on DRM for digital HF broadcasting long ago.

Like I asked, "Does anyone own a DRM shortwave receiver?".

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I believe the DRM issue is tied up with two things.
1. There is nothing on SW any more much less spending money on DRM.
2. Like IBOC. DRM charges for a license to put DRM into a radio.

I was going to modify my Kenwood to receive DRM via freeware but then they want me to tap into the IF stages and bring that out. Sorry but I am not up for that modification. If I could receive DRM via a direct sound card input (similar to PSK31) I would certainly attempt that.
 
I believe the DRM issue is tied up with two things.
1. There is nothing on SW any more much less spending money on DRM.

There are a few DRM stations around. Radio New Zealand International has an extensive DRM service - all day except for 1159-1550 UTC. Link: RNZI

I was going to modify my Kenwood to receive DRM via freeware but then they want me to tap into the IF stages and bring that out. Sorry but I am not up for that modification. If I could receive DRM via a direct sound card input (similar to PSK31) I would certainly attempt that.

Few if any AM or shortwave radios have the audio bandwidth (12 kHz) to pass the DRM signal. That's why the IF is tapped before any filtering is applied.
 
Don't think that the sound card on my laptop has 12kHz capability either.

It probably does. Any sound card made in the last 20 years can sample at 44 kHz, which allows for 22 kHz audio.
 
I built one a couple of years ago with this:

http://sourceforge.net/projects/drm/

The modification of the IF is not that difficult, and it worked OK in a noise-free environment. But all I was able to hear at the time were transmissions in another language. It had the clanky-swooshy digital sound of HD radio and low-bitrate webcasts. But it was a fun experiment. The big advantage that DRM has vs. HD is bandwidth efficiency, and the fact that the allocation scheme actually allows for the occupied bandwidth of a signal, rather than just assuming that the guard bands are vacant.

Dave B.
 
Is there a trick to typing one of those "little s making love to another little s" characters, like the FCC uses?
 
Is there a trick to typing one of those "little s making love to another little s" characters, like the FCC uses?

You mean §? In Windows it's Alt+0167.

And it's not just the FCC. That is a standard symbol denoting a section of a law or regulation.
 
I believe the DRM issue is tied up with two things.
2. Like IBOC. DRM charges for a license to put DRM into a radio.

Not exactly like IBOC. DRM does have patented components, but that's no different than patented components in other technologies...incremental cost typically passed along to the consumer. Far different from the perpetual 3% of gross revenues required by iBiquity's license. Those patents will eventually expire, too, like they have with Eureka 147.

SW can't move markets, though, that's for sure. It'll be interesting to see what happens if/when the BRIC countries begin investing in DRM. India's moving in that direction for AM and SW, the rest are still up in the air.

There is also DRM+, which works on FM, but hasn't really gotten any traction outside of tests.
 
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