DRM Software Radio Forums

DRM Software Radio Forums (http://www.drmrx.org/forum/index.php)
-   Reception Results - Recent Posts (http://www.drmrx.org/forum/forumdisplay.php?f=22)
-   -   Radio Romania 11650 kHz DRM 16-QAM Spanish (http://www.drmrx.org/forum/showthread.php?t=2792)

Braccini 08-04-2018 22:57

Radio Romania 11650 kHz DRM 16-QAM Spanish
 
Hello,

Dear Mr. Braccini,

Due of last days tuning difficulties with one of our transmitters, we had
to change to analog AM 13810 kHz and run DRM 15670 kHz.
We are in progress to modify the settings of one transmitter to DRM mode D,
16 QAM (recommended to be used for long distances) and keep the other one
with actual settings for near distances.
According with prediction for new A18 season, the best bands are 13 MHz and
15 MHz - they are little bit better than 11 MHz and 13 MHz.
As differences are not significant, we propose to run a test as follow:
this week we'll continue running 15670 kHz in DRM, and next week we'll test
11650 kHz in DRM (this is completely clear channel), and kindly ask you to
send us a feedback.

Thank you and best regards.

RADIOCOM

Braccini 08-04-2018 23:05

RRI 11650 kHz DRM in South Brazil
 
Amazing signal, without breakes in Montenegro-RS, Brazil. I'm very happy, because RRI answer my request, changing to 16-QAM MSC and broadcasting in 25mb (11650 kHz), excelente band for A18 and B18 cycles and modulation. It's the result of a hard work, sending various e-mais and calling to RADIOCOM and Radio Romania. Thanks for all 🙏🙏🙏

VIDEO: https://youtu.be/75K19ItSyAM

Digger 08-04-2018 23:45

At what time? In UTC please.

Braccini 09-04-2018 00:20

Quote:

Originally Posted by Digger
At what time? In UTC please.

Hello Terje, RRI is broadcasting at 21h UTC to South America in this frequency. Clint 73 from Brazil!

tpreitzel 09-04-2018 01:25

Good for you, Clint. I kind of laugh at RRI's rationale, though, which is typical of an engineer's study, not experience. Use 16 QAM modulation ALWAYS on shortwave, RRI! Mode D ought to be interesting, though. ;) At least you managed to twist their arm enough to try it. LoL ... Great job!

Braccini 09-04-2018 05:12

Quote:

Originally Posted by tpreitzel
Good for you, Clint. I kind of laugh at RRI's rationale, though, which is typical of an engineer's study, not experience. Use 16 QAM modulation ALWAYS on shortwave, RRI! Mode D ought to be interesting, though. ;) At least you managed to twist their arm enough to try it. LoL ... Great job!

Thanks, I hope it extends to all DRM transmissions of RRI 😊

Digger 09-04-2018 05:26

Good heavens! Mode C is bad enough. Audio from Mode D is probably "D"readful! However Clint, thanks for the time info. Just for fun I'll sharpen my antenna in Japan!

Braccini 09-04-2018 13:03

Quote:

Originally Posted by Digger
Good heavens! Mode C is bad enough. Audio from Mode D is probably "D"readful! However Clint, thanks for the time info. Just for fun I'll sharpen my antenna in Japan!

They are using B mode, but need set to use AAC+ codec (+SBR). It's possible with 16-QAM onde the MSC. Clint 73!

AF4MP 09-04-2018 22:29

RRI, 11650 kHz, Reception near Atlanta, Georgia, USA
 
1 Attachment(s)
This afternoon's reception - beamed to South America - 9.05% audio decoded, 13.49 dB max SNR.

Digger 09-04-2018 23:58

2 Attachment(s)
No traces of DRM on this frequency in Japan this morning. 11 MHz is pretty full of chirps here at my temporary location. However, sometimes I can see RRI via the back of the beam.

Here is a short log which I made with a Kiwi SDR in Rio Grande da Serra, Brazil. RRI used Mode B, 11 kbps and 16 QAM. The result was 3000 Hz audio bandwidth. The audio quality was therefore not the best, but the reception was stable.

Braccini 10-04-2018 10:21

RRI 11650 kHz DRM in South Brazil 9 APR 18
 
Today I had failures in the second half hour of transmission, possibly by propagation, but it was not a big problem, because they had listeners who did not have flaws. I ask that broadcaster always maintain 300 KW of power.

VIDEO: https://youtu.be/W_a8G07jzk8

Digger 10-04-2018 13:27

I think it's 90 kW DRM.

AF4MP 10-04-2018 14:54

Quote:

Originally Posted by Digger
The result was 3000 Hz audio bandwidth. The audio quality was therefore not the best, but the reception was stable.


Hi Terje,

The RRI 9760 kHz transmission is also now using 16 QAM with its low bit rate of 11.64 kbps. I posted the audio 3.5 kHz bandwidth plot in that thread.

Although the audio sounds "pretty good" it is, after all, the same or very similar bandwidth to a telephone circuit. A 3.5 kHz wide SSB transmission would sound just as good, and have much greater range.

As 16 QAM provides only telephone type quality, and no extra features such as Journaline, etc., and it requires a wider RF bandwidth and higher SNR to receive than analog SSB channel; I'm trying to understand the rationale of using the low fidelity mode?

My interest and embrace of "DRM" is its high quality audio plus extra features that cannot be achieved by analog transmission. 16 QAM does not provide that.

tpreitzel 10-04-2018 18:13

Quote:

Originally Posted by AF4MP
Hi Terje,

The RRI 9760 kHz transmission is also now using 16 QAM with its low bit rate of 11.64 kbps. I posted the audio 3.5 kHz bandwidth plot in that thread.

Although the audio sounds "pretty good" it is, after all, the same or very similar bandwidth to a telephone circuit. A 3.5 kHz wide SSB transmission would sound just as good, and have much greater range.

As 16 QAM provides only telephone type quality, and no extra features such as Journaline, etc., and it requires a wider RF bandwidth and higher SNR to receive than analog SSB channel; I'm trying to understand the rationale of using the low fidelity mode?

My interest and embrace of "DRM" is its high quality audio plus extra features that cannot be achieved by analog transmission. 16 QAM does not provide that.


Nonsense with a capital "N" on several fronts. Several digital SW broadcasters like VoR had absolutely no problem using Journaline with 16 QAM modulation. 16 QAM modulation fully support SBR as well which is certainly better than listening to large blocks of silence with 64 QAM. If higher audio quality is desired, try the medium wave band instead of shortwave.

AF4MP 10-04-2018 22:48

No signal received on 11650 kHz this afternoon.


All times are GMT. The time now is 01:56.

Powered by vBulletin Version 3.5.3
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.