Monday, June 22, 2015

Solarstorm hits during RNZI reception

Here is an intriguing graph from DRM Log-Plotter while I was listening to RNZI on 17675kHz tonight. You can see that "Old Mister Sun" took out a good chunk for the program, with the SNR plummeting to zero at one point. The program resumed eventually at typical SNR levels.

Ironically, New Zealand's national aircraft radar was also effected at the same time, grounding all NZ flights! Coincidence?

Friday, June 5, 2015

RNZI - DRM vs AM audio bandwidth

I've done this comparison before but here is a quick double-snapshot of RNZI in DRM and in AM.

This was done with the "Music 101" program host Emma Smith IDing the show, first in DRM on 17675 kHz and then in AM on 15720 kHz. You can see that DRM gains you 5 kHz of audio bandwidth. At the audio bitrate of 15.5 kbps using AAC+, RNZI sounds great - especially when you consider that it is reaching me from nearly 7000 miles away.

No argument, RNZI in AM does perfectly well here, but it is clear that DRM delivers the goods. Also note the level of audio compression on the AM signal. In spreading out the DRM signal, we also gain delightful dynamic range, which is what the recent CD loudness wars have been all about. Imagine how much better xHE-AAC would be!

Tuesday, June 2, 2015

Brazil test report from the DRM consortium

The original release is here:

"On May 28th Brazil experienced  the first DRM broadcast in short wave originating in Brazil mainly for Brazil.

The public broadcaster in Brazil, EBC, with the collaboration of partners broadcast in DRM in the afternoon of the 28th with 130W in DRM in the frequency of 9755kHz. The coverage area is predicted to encompass North – Amazonia as well as the south of the country, the richest part of Brazil and other neighbouring countries.

Despite the low power used the DRM signal has been already received successfully in parts of the country, being audible in quality in the Sao Paolo State at about 800km away from the transmission site in Brasilia. The audio of the Amazon National Radio was received there in excellent digital quality.

The transmission system was put together with Brazilian know how and with the assistance of EBC and key members of the DRM Brazilian Platform like Rafael Diniz, researcher at the Catholic University of Rio de Janeiro. Staff of the EBC and the Ministry of Communications chose to broadcast using one antenna system at Rodeador Park (EBC’s High Power SW Broadcast Centre). The antenna used has 16dB gain and north-south radiation pattern.

Tests are continuing and more measurements and feedback are to come in the next days and months."

Sunday, May 31, 2015

Great news from Brazil

Update 20150602:

"Today arrived other amplifier made by a DRM-Brasil member, all without involving money (this is why things walk so slow). So EBC people will carry some tests with it, and after that transmission should restart, with a signal with better MER.
As the setup has little power, the crew involved is trying optimize the quality of the signal. So no signal today, and nothing happened yesterday also..."

This is not only good but triumphant news! Thanks to Brother Rafael.
"Tests will resume on Monday (1st June).
We'll inform the frequency soon.

Btw, on Thursday happened the first DRM SW transmission in Brazil! With 130W signal at 9755kHz was received by Claudio 780 km far away.

Big thanks to Michael Feilen, all guys at EBC and Ministry of Communications
involved in the trial.

Next week we'll be able to get another final stage amplifier in order to check if
we can get more power out."

Friday, May 29, 2015

Amazonia test reception

From Claudio PY2GVY: 780 km, from Brasilia, (GH64ah) to Limeira, SP (GG67hk), 100W, 9.755 KHz.