hello,


I just modified my home receiver to listen to DRM,
and I'd liked to share my thoughts with other listeners.
I'm not by no means an expert, just wired the mixer
into my Rx and tried to listen to DRM stations.
Signal input spectrum looks good and the software
successfully decodes the signal.
Problem is that 17-18 dB SNR is always needed in order to
get the audio, and such SNR is just too hard to get for me.
So far I have been unable to get more than 10-15 seconds
of audio in a row, and listening to the program is barely
impossible.
Searching over the net I found that DRM enthusiasts equipped
with DX type of rigs also get no audio below say 15-16 dB SNR.
My modified receiver is a Hitachi KH-WS1, not a DX performance
kind of radio, just a shortwave home receiver, but
DRM is meant as a long term replacement of home radios,
isn't that ?
With such receiver I have no problems listening to analog
european BCs, while the very same BCs (DW) are almost
impossible to hear via DRM.
I'm curious to know if I'm missing something or other listeners
have the same experience too.
If signals this strong are needed to hear DRM audio I think
DRM will have a hard time to replace analog broadcasting.



--
-- Maurizio Galaverni ceci n'est pas une pipe |

Maurizio,

I can typically receive DRM with a SNR of 14 dB or higher; however, the
real-world difference between 14 dB and your experience of 17 dB is
negligible.

I find two other problems with DRM:

1. Interference and/or noise: the only DRM transmission that I can
reliably receive is the block of transmissions (BBC, RCI, RNW, DW, R.
Sweden, Vatican R.) from the RCI transmitter in Sackville, New Brunswick.
Even though Sackville is "next door" in shortwave terms to where I live, I
still have trouble decoding DRM when there is an adjacent station. With the
switch to the winter schedule, the DRM block is now using 49m for a while.
I have a very hard time getting DRM to work on 49m. There are just too many
other stations on 49m at night.

2. Audio quality: even at it's best, the 20.9 kbps stream can't comapre in
audio quality to a regular AM transmission. It's very interesting to do a
compare/contrast between the DRM feed from Sackville versus an AM broadcast
from the same location.

Just because something is digital doesn't mean it's better.

Bob


"Maurizio Galaverni" wrote in message
...

hello,


I just modified my home receiver to listen to DRM,
and I'd liked to share my thoughts with other listeners.
I'm not by no means an expert, just wired the mixer
into my Rx and tried to listen to DRM stations.
Signal input spectrum looks good and the software
successfully decodes the signal.
Problem is that 17-18 dB SNR is always needed in order to
get the audio, and such SNR is just too hard to get for me.
So far I have been unable to get more than 10-15 seconds
of audio in a row, and listening to the program is barely
impossible.
Searching over the net I found that DRM enthusiasts equipped
with DX type of rigs also get no audio below say 15-16 dB SNR.
My modified receiver is a Hitachi KH-WS1, not a DX performance
kind of radio, just a shortwave home receiver, but
DRM is meant as a long term replacement of home radios,
isn't that ?
With such receiver I have no problems listening to analog
european BCs, while the very same BCs (DW) are almost
impossible to hear via DRM.
I'm curious to know if I'm missing something or other listeners
have the same experience too.
If signals this strong are needed to hear DRM audio I think
DRM will have a hard time to replace analog broadcasting.



--
-- Maurizio Galaverni ceci n'est pas une pipe |

On Sun, 23 Nov 2003 19:05:15 GMT, Maurizio Galaverni wrote:

Problem is that 17-18 dB SNR is always needed in order to
get the audio, and such SNR is just too hard to get for me.
So far I have been unable to get more than 10-15 seconds
of audio in a row, and listening to the program is barely
impossible.

With the propagation being as bad as it has been this year, I don't often get
consistent DRM reception with an indoor antenna. One thing that I found can
increase the SNR, however, is experimenting with the audio level -- not with the
level control on the sound card, but with a potentiometer between the radio and
the computer. This is on a Ten-Tec RX-320, so it may not apply to your radio.

In article ,
"Robert Sillett" wrote:

Maurizio,

I can typically receive DRM with a SNR of 14 dB or higher; however, the
real-world difference between 14 dB and your experience of 17 dB is
negligible.

I find two other problems with DRM:

1. Interference and/or noise: the only DRM transmission that I can
reliably receive is the block of transmissions (BBC, RCI, RNW, DW, R.
Sweden, Vatican R.) from the RCI transmitter in Sackville, New Brunswick.
Even though Sackville is "next door" in shortwave terms to where I live, I
still have trouble decoding DRM when there is an adjacent station. With the
switch to the winter schedule, the DRM block is now using 49m for a while.
I have a very hard time getting DRM to work on 49m. There are just too many
other stations on 49m at night.

2. Audio quality: even at it's best, the 20.9 kbps stream can't comapre in
audio quality to a regular AM transmission. It's very interesting to do a
compare/contrast between the DRM feed from Sackville versus an AM broadcast
from the same location.

Just because something is digital doesn't mean it's better.

Bob


"Maurizio Galaverni" wrote in message
...

hello,


I just modified my home receiver to listen to DRM,
and I'd liked to share my thoughts with other listeners.
I'm not by no means an expert, just wired the mixer
into my Rx and tried to listen to DRM stations.
Signal input spectrum looks good and the software
successfully decodes the signal.
Problem is that 17-18 dB SNR is always needed in order to
get the audio, and such SNR is just too hard to get for me.
So far I have been unable to get more than 10-15 seconds
of audio in a row, and listening to the program is barely
impossible.
Searching over the net I found that DRM enthusiasts equipped
with DX type of rigs also get no audio below say 15-16 dB SNR.
My modified receiver is a Hitachi KH-WS1, not a DX performance
kind of radio, just a shortwave home receiver, but
DRM is meant as a long term replacement of home radios,
isn't that ?
With such receiver I have no problems listening to analog
european BCs, while the very same BCs (DW) are almost
impossible to hear via DRM.
I'm curious to know if I'm missing something or other listeners
have the same experience too.
If signals this strong are needed to hear DRM audio I think
DRM will have a hard time to replace analog broadcasting.


In general if you are trying to transfer the same intelligence over the
same bandwidth and frequency it won't be better.

Deception Radio Mondiale.

--
Telamon
Ventura, California

Just curious, how did you modify your Hitachi KH-WS1 for DRM? I also have
one of those but if your experience of DRM is typical maybe it's not woth
while modifying it.

Alyn Scott

"Maurizio Galaverni" wrote in message
...

hello,


I just modified my home receiver to listen to DRM,
and I'd liked to share my thoughts with other listeners.
I'm not by no means an expert, just wired the mixer
into my Rx and tried to listen to DRM stations.
Signal input spectrum looks good and the software
successfully decodes the signal.
Problem is that 17-18 dB SNR is always needed in order to
get the audio, and such SNR is just too hard to get for me.
So far I have been unable to get more than 10-15 seconds
of audio in a row, and listening to the program is barely
impossible.
Searching over the net I found that DRM enthusiasts equipped
with DX type of rigs also get no audio below say 15-16 dB SNR.
My modified receiver is a Hitachi KH-WS1, not a DX performance
kind of radio, just a shortwave home receiver, but
DRM is meant as a long term replacement of home radios,
isn't that ?
With such receiver I have no problems listening to analog
european BCs, while the very same BCs (DW) are almost
impossible to hear via DRM.
I'm curious to know if I'm missing something or other listeners
have the same experience too.
If signals this strong are needed to hear DRM audio I think
DRM will have a hard time to replace analog broadcasting.



--
-- Maurizio Galaverni ceci n'est pas une pipe |