I've briefly reviewed the documentation on Spark ( www.drm-sender.de ) and it just might accomplish this task on broadcasting DRM with a 100 MW transmitter such as the TH. I'll be saving some money (~$500) to buy the necessary TX hardware.
In the meantime, most of you ALREADY have the necessary hardware. For the curious experimenter, why don't some of you download the trial version of Spark and see if you can use it to broadcast an OFDM signal via line-out on your sound-card to the TH TX? I'll be experimenting over the course of the next 6 months or so.
Because I'm saving at least $30 in shipping costs by purchasing one of the packages versus purchasing the components separately, I'm a new low-power, Part 15 broadcaster for a price of $550 and the cost of my time. I'm a renegade who isn't particularly fond of government so my broadcasts won't win any popularity awards. Truth is NEVER readily accepted. 😉 However, I haven't received the items yet. I mainly purchased this low-power kit for experimenting with DRM. If my tests using DRM fail with this transmitter, I can always broadcast analog.
I'll be using a combination of the restricted Spark * along with an older version of DReaM for my tests of DRM. IIUC, a new software transmitter and receiver for DRM is being developed for GNU Radio so we'll have to wait and see if three possibilities for transmitting DRM become available.
* Not too many low-power broadcasters can justify ~ $5000 for the licensed version of Spark.
tpreitzel, I for one am looking forward to your experimentation.
You mentioned doing drm OR analog. Is it possible to do both together, as with HD?
Carl,
Technically ... but I'm unsure about the capabilities of the software that I'll be using.
A simulcast can be done on a standard 10 Khz channel with the LSB occupied by a 5 KHz analog signal while the USB is occupied by the DRM signal. Bit rates for a 5 KHz signal range on the low-end from ~ 7 kbits/second to 16 kbits/second. I haven't really looked closely at the software capabilities, yet.
This is all fine, however isn't there one crucial missing piece of this DRM puzzle?
Who's gonna receive it on their current radio?
Hmm...
RFB
I would love to stack a DRM signal on my carrier.
Any folks in the nearby public who failed to listen would be labeled as "not cool".
My plans to go DRM keep on failing, one reason is that Mike the developer made a trial version for Spark software, and he wants everyone to go to the site request a download. The sad part is that he takes long to send me the email with the download link. I requested it before, but when I had a major computer crash, I lost the software and the email he sent me. Also as for reception, that there is a hard to thing to do because I need a special 455 kHz to 12 kHz down converter to connect to a receiver with a 455 kHz out put jack. I also need to figure out on how to connect the DRM signal output to the AM transmitter.
As for HD Radio,
HD Radio here in the United States is a failure professional and hobbyist. Professionals have dropped AM 1230s HD radio signal here in Norfolk, VA, and also there are others shutting down their HD AM signal. Also on FM, there is nothing to listen to, because there is nothing but boring pop music HD-2 stations, and the don't stay locked in to enjoy them.
I am going to make this plan come true to get DRM on the air as soon as possible within part 15 regulations. DRM is just a digital mode, and it will help end the HD radio monopoly, and help make DRM available for all parts of short wave, AM, and long wave broadcasting and part and pirate broadcasting. Also XFM on Shortwave went DRM before as a test transmission.
Just right now it's being experimented and tested locally using part 15 FM. It wil be tested soon when I get that 455 kHz to 12 kHz downconverter. I might test it using soft ware defined radio.
Anyone with an Software defined radio can receive the DRM signal than a regular receiver connected to a down converter. The DRM signal will produce a double side band signal with your analog signal. Also there is a way to make it independent which this is what most short wave radio stations do anyways. I think the MW signals are adjecent to the analog signal anyways. Best thing to do is experiment with it during the daytime transmissions.
Really enjoy hearing about the DRM experiments with Part 15 transmitters, especially MW and SW.
Keep perfecting it.