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Old 24-07-2012, 19:44   #1
tpreitzel
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DRM Broadcasting Via Low-Power Part 15 CFR's Title 47

Does anyone know if Part 15 rules of CFR's Title 47 allow UNLICENSED, low-power broadcasting of DRM on MW frequencies in the US? Or is all broadcasting of DRM, both licensed and unlicensed, banned on MW frequencies in the USA?

TIA

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Old 27-07-2012, 14:43   #2
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In response to my questioning elsewhere, the UNOFFICIAL consensus seems to be that the FCC PROBABLY doesn't care as long as the transmitter conforms to Title 47, Part 15.219 rules.

Given the potential removal of the legal barrier, is it possible technically to broadcast DRM at low-power levels of 100 mW? I've briefly scanned some documents of tests with power levels at 1 W, but not at 1/10 that power level.

If possible, even I might start a local digital community radio station broadcasting DRM in the USA if I can overcome the technical and equipment hurdles.

Firstly, I need a Title 47, Part 15.219 transmitter capable of transmitting DRM....

Last edited by tpreitzel : 30-04-2013 at 10:25.
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Old 27-08-2012, 03:59   #3
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I've inquired with both Radio Systems and Nautel about offering a modified version of Radio Systems' I.AM.Radio transmitter which is capable of transmitting DRM. Since Radio Systems has sold thousands of their I.AM.Radio transmitters, the market is definitely present for CERTIFIED Title 47, Part 15.219 systems. Adding DRM capability to the I.AM.Radio transmitter is the next logical step, but will the added expense justify the effort? Over the first couple of years, I think so as the market will be a virtual monopoly for a company.

Here's the text of my e-mail to Nautel:


"Although the USA has authorized iBiquity for commercial transmission of DRM on the medium wave (MW) band, Title 47, Part 15.219 rules allow for unlicensed broadcasting on MW in the USA. Currently, I use Radio Systems' I A.M. Radio transmitter with their external ATU for unlicensed, analog broadcasts on the MW band in the USA. I've informed Radio Systems about my desire to see a low-power, Title 47, Part 15.219 MW DRM transmitter for sale. I'm extending this same offer to Nautel as a Canadian manufacturer since I believe a significant market exists for a CERTIFIED Part 15.219 DRM transmitter. Radio Systems has literally sold thousands of their Title 47, Part 15.219 analog transmitters and DRM would allow unlicensed broadcasters to effectively compete qualitatively on MW with larger commercial broadcasters on FM. Manufacturing and offering such a low-power, Title 47 Part 15.219 MW DRM transmitter could seriously help drive a demand for eventual digitization of ALL bands with DRM including a possible review of iBiquity's current monopoly on the MW and FM bands in the USA. Since most Title 47, Part 15.219 broadcasters deliver their services to their respective communities primarily for the love of radio, any retail cost for such a low-power MW DRM transmitter would need to be reasonable. Since Radio Systems' I A.M. Radio system including both their analog MW transmitter and external ATU can be purchased for $500, is it reasonable to propose an offering of a Title 47, Part 15.219 MW DRM transmitter only driven into a load consisting of Radio Systems' external ATU for less than $1,000 USD? Personally, I think this proposal is reasonable, but some research would be required including any costs to CERTIFY such a transmitter for use with Radio Systems' external ATU. Maybe, a collaboration with Radio Systems on producing such a Title 47, Part 15.219 MW DRM transmitter is even feasible. Personally, I'd buy such a low-power MW DRM transmitter without a second thought.

I sincerely hope that this e-mail isn't flippantly dismissed as I'm convinced a market for such a low-power MW DRM transmitter exists."

Last edited by tpreitzel : 30-04-2013 at 10:46.
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Old 28-08-2012, 16:38   #4
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I'll continue looking into this subject over time as unlicensed broadcasting via Part 15.219 needs to be capable of using digital modulation. I'm also interested in resurrecting AM Stereo via Motorola's C-QUAM/AMAX specification. I know that the I AM Radio transmitter can be modified for C-QUAM, but such modifications will void their Part 15 certification.

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Old 19-05-2013, 02:52   #5
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On second thought ...

I decided to record a portion of REE's digital broadcast on 9630 kHz this evening via gqrx. I saved this recorded file and fed the input into I.AM.Radio's Part 15.219 transmitter. To my amazement, my DR111 recognized parts of the signal as the SNR indicator was occasionally showing levels which were very erratic, i.e. 5 then 10 followed by 0. I tried normalizing the recorded file, i.e. increasing the level, but this change made the situation even worse as NO SNR level was then detected by the DR111 receiver. Unfortunately, I didn't save the original copy. However, I plan on recording more DRM broadcasts and adjusting the level of the recorded files. I was experimenting with DRM MW @ 1660 kHz.

I'm beginning to think the problem of transmitting DRM with the I.AM.Radio transmitter is at least partly related to the AGC function on its line input. In my brief experiment, I didn't decode any audio, just received a few brief indicators of a signal with a widely varying SNR....

Interesting and worth more experimentation ... Maybe, if I can just find and set the appropriate level of a recorded file for the I.AM.Radio's line input ...

Addendum: I recorded further broadcasts and piped the feed to the I.AM.Radio transmitter, but my DR111 always receives the signal for just a second or so before the signal disappears and then repeats the process over and over again. Hence, I never receive a SDC.

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Old 22-10-2013, 05:31   #6
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ATTENTION Greeks from Athens!

I just recently discovered that AspiSys which is located in Athens used to sell a Title 47, Part 15 DRM transmitter, the DrMax-1! A link to a YouTube video is located near the bottom of the page of the link to e-bay. However, I can't seem to get a response to my questions via e-mail. Apparently, the DrMax-1 was never formally introduced or it didn't last long. Damn! I didn't arrive on the DRM scene until 2011. I want to buy this transmitter and my hope is someone in Athens can find more information about the status of the DrMax-1 by visiting their company which is located:

Avlidos 26b
Athens 11527
Greece (EU)

http://www.ebay.com/itm/DRM-Transmit...p2047675.l2557

See www.aspisys.com for more information..

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Old 22-10-2013, 08:47   #7
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Although I haven't used my e-bay account in years, I managed to send a message to the seller, aspisys, once I remembered my old password. Hopefully, aspisys, will respond via e-bay's e-mail system.
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Old 22-10-2013, 09:40   #8
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@tpreitzel

Hi,
I sent you a PM.
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Old 22-10-2013, 17:11   #9
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It's great to know that AspiSys still sells their DrMax-1. Since DReaM 2.1 can now transmit DRM using the Opus codec, I'm intent on accomplishing my goal of broadcasting DRM on unlicensed LPAM in the USA even IF I'm the only one listening. However, I highly doubt that I'll be the only one listening. It'll be absolutely GREAT if this project sees the light of day and I hope other Part 15 LPAM broadcasters in the USA do likewise.

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Old 23-10-2013, 15:14   #10
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Quote:
Originally Posted by tpreitzel
It's great to know that AspiSys still sells their DrMax-1. Since DReaM 2.1 can now transmit DRM using the Opus codec
Good, good, good :-) That sounds really good!

Quote:
Originally Posted by tpreitzel
I'm intent on accomplishing my goal of broadcasting DRM on unlicensed LPAM in the USA even IF I'm the only one listening. However, I highly doubt that I'll be the only one listening.
I hope your undertaking will inspire others on something like that. Keep us informed on the topic. It is very interesting.
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Old 23-10-2013, 23:19   #11
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Hi
This kit:
http://fivedash.com/index.php?main_p...9dc5e4dba1a4ce
shoud be capable of DRM transmission .
The PLL used covers from 1Mhz to 40 Mhz.
It uses SMD so good skills in electronics is required.
Price is very competitive.
Buying the ready built 160m version is a good idea but it is not actually available

Last edited by F1BJB : 23-10-2013 at 23:22.
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Old 24-10-2013, 03:21   #12
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Quote:
Originally Posted by F1BJB
Hi
This kit:
http://fivedash.com/index.php?main_p...9dc5e4dba1a4ce
shoud be capable of DRM transmission .
The PLL used covers from 1Mhz to 40 Mhz.
It uses SMD so good skills in electronics is required.
Price is very competitive.
Buying the ready built 160m version is a good idea but it is not actually available

It's unfortunate that a 100 mW version isn't available. Thus far, I've tried TWICE to contact AspiSys via their e-mail address with no response. I'll give them a week to respond before trying again as they may be busy.

Or AspiSys' e-mail system may be using spam filters which block proxies. I use HTTP and FTP proxies exclusively for electronic mail and browsing the World Wide Web.

Last edited by tpreitzel : 24-10-2013 at 05:54.
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Old 24-10-2013, 07:27   #13
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A 10 dB attenuator on the antenna jack would do the job.
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Old 24-10-2013, 07:32   #14
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I don't think an attenuator on the antenna meets the requirements of Title 47, Part 15 rules.
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Old 24-10-2013, 09:17   #15
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I don't know FCC rules.May be a link would help
If it is 100mW AM carrier power This means 400mW peak modulation power
Not far from the 1 W peak power here
Reducing the 12 V power supply could help too.
And DRM has a big (10 dB) difference between peak and average power this should help.
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