IAW with the title, is this possibility legal? Are DRM broadcasts forbidden by licensed "full" power MW transmissions or are ALL (including unlicensed Part 15) DRM broadcasts on the MW band banned in the USA?
I haven't found much discussing this subject via the major search engines.
tpreitzel raises a question deserving of study, and I'm already starting to check around.
My curiosity about Digital Radio Mondiale (DRM) stems from many favorable remarks about it made by Keith Perron of pcjmedia,com, an international program producer. He is building a 20kW SW relay transmitter in Taiwan that will broadcast part time in DRM, otherwise in analog.
The horrible so-called HD that we have in the US now is licensed, and would be too expensive for part 15, so I will try to learn about DRM.
Give me 20-minutes.
The description of DRM is very promising
http://en.wikipedia.org/wiki/Digital_Radio_Mondiale
The FCC expressly permits it for HF (shortwave from the U.S.)
I didn't see anything mentioned about AM radio in the U.S., but maybe someone else will know.
"I didn't see anything mentioned about AM radio in the U.S"
Won't be any mention while iBiquity has the monopoly already well entrenched in what's left of the industry.
RFB
...if DRM is legal on the AM band. I'd broadcast in analog on 1610 and in DRM digital on 1660.
The hardest part would be getting people to listen to the DRM signal since all digital AM radios in the US use the horrible IBOC standard. People would have to buy European radios to pick it up.
I have a question about DRM. would multicasting be possible on AM? If so, I would love to do an all reggae station on WCHX-DRM2 called Half Baked Radio. I know alot of reggae fans who are probably willing to buy a European radio to hear some Bob Marley.
"The hardest part would be getting people to listen to the DRM signal since all digital AM radios in the US use the horrible IBOC standard. People would have to buy European radios to pick it up."
There is your major roadblock. It's not included nor will receiver manufacturers start building radios with different decoders in them just to test the waters. That was prove a major disaster decision back in the 80's with AM stereo and the standard wars and letting the dumb down market decide.
I can just imagine the fiasco these days with convincing manufacturers to let the market decide when obviously the result will be the same as before, with the exception that today you got iPad and iPhone and iMobile and sattelite etc etc.
But it's not the first roadblock to overcome. iBiquity is your first hurdle to jump through.
RFB
After reading the message from RFB I realized we could call part 15 by the clever name iPart.
What about part 15 IBOC, but using an all digital mode on a completely different frequency. Example: analog on 1610, IBOC on 1670 (far enough away to eliminate interference to analog)
I know IBOC isn't as good (or as cheap) as DRM, BUT every digital AM receiver has it. People who already have HD-AM receivers could pick up Channel X Digital.
"What about part 15 IBOC"
That would be nice, however the license alone just to use that proprietary digital format would be impractical.
Then throw in the cost of TX manufacturers also having to pay for that license to put that format encoder into the kit...ha..that kit would be the most expensive kit ever.
Plus, you are only thinking locally with the channel separation between the analog station and HD station. What if someone likes that distant station on 1650 and your HD IBOC thrasher trashes their reception?
CQUAM!!! I SAY GO CQUAM!!! Most HD AM radios have the CQUAM decoder and CQUAM does not splash and hash and trash the band. And the doppler effect has no effect on CQUAM as it does on IBOC.
RFB
C-QUAM transmitter or some kind of generator to put a stereo signal through a mono transmitter, I would. I would love to broadcast in stereo. In fact, my car has a stereo tuner. It would be amazing to hear my station in stereo while driving around.
As for part 15 IBOC, wouldn't the "I-Buzz" only go as far as 100mW will travel. If so, the only area affected by the potential interference would be at the most 5 miles from the transmitter.
That being said, I'm not a fan of IBOC. The only reason I suggest it is because it's the only digital format on broadcast bands in this country, even though it is a terrible system.
There is a station about 10 miles
away on 1550 that runs 5 kW during
the day. It ran IBOC for a while.
I had trouble decoding it. (I have an
"IBOC" radio.)
There also was a station on 1290 running
500 watts daytime that ran IBOC. I
couldn't decode it. I was right here
in my town!
C-Quam is the way to go. It does not
degrade. I also have a radio that gets
C-Quam stereo. You can still buy them
from Japan.
There are still quite a few C-Quam enthusiasts
around. A guy had a transmitter kit for
a while, but it isn't available anymore.
As for DRM, I have always wanted to try to
receive it. As a loyal BBC listener, who
misses getting the BBC on shortwave, I
had been looking for frequencies that it
was still on, even if they were not beaming
to North America.
The BBC runs DRM on 3955, last I checked.
Since I am on the east coast, I used to
listen to them on 3955 when they were
transmitting AM. I believe I have heard
their DRM signal here, at least it sounds
like it. To hear them on DRM would be
cool.
Bruce, DRS2
It sound's Incredible! 'Nuff said.
Maybe, I should have phrased my question this way: Does the FCC care whether an unlicensed, low-power broadcast is digital or analog as long as field strength limitations in the Part 15 rules aren't exceeded?
I'll probably send a letter to a couple of my non-representatives and ask them to inquire with the FCC about this issue. Personally, I want DRM due to the clarity of its signal and versatility. Technically, with DRM30, it's even possible to broadcast low frame rate video via Diveemo.
I am not always known as "Mr. Opinion," but today I feel like I'm "right" about everything I have an opinion about.
The part 15 rules do not say anything about what can or can not be modulated on part 15 AM transmitters.
THEREFORE you can modulate ANYTHING.
I like to make up music by whistling little tunes. That could be a whole format on a part 15 station.
Test Tones 24-Hours a Day would appeal to me.
Really vulgar Morse code messages might go unnoticed for years.
Put the digital output from a clock chip on the air. No reason for it, but, DO IT.
I don't think anybody cares
what mode you use. I'd
like to try double sideband
suppressed carrier some day.
I'm serious about WANTING to
try it, anyway.
If I had the time, the money,
the engineering know how, etc.
Yup, I agree with Carl. Try
any mode that you want. That's
what the longwave Part 15ers do.
Best Wishes,
Bruce, DRS2