View Single Post
  #1   Report Post  
Old February 7th 07, 02:53 PM posted to aus.radio.broadcast,alt.radio.digital,rec.radio.shortwave,alt.radio.broadcasting
The Philestine The Philestine is offline
external usenet poster
 
First recorded activity by RadioBanter: Feb 2007
Posts: 4
Default RDS-FM versus AM-SS - Data steam systems for radio

G'day,

Last week I visited a major electrical department store that was staging a
closing-down sale.

I admit I was searching for a bargain, but I had left it too late since all
the good stuff I wanted was sold out - TVs, computers, 5.1 Surround Sound
systems etc.

Fortunately I did manage to find a nice china cabinet that was on sale at
half price. I knew my wife was keen to get a new piece of furniture, and
after sending her some pictures of it from my mobile phone camera, we
decided to buy it. So the trip to the store proved to be a good move.

I also came across a radio set that I had never seen before. It too was on
sale at half price and I very nearly bought it. The only thing that stopped
me was the fact that it appeared to not tune across the whole AM frequency
spectrum, which in Australia ranges from 522 Khz to 1602 Khz for the
commercial broadcast stations, and 1611 Khz to 1710 Khz for the mostly
narrowcast stations. Being an avid narrowcaster, I needed it to tune as high
as 1710 so that I could listen to the few narrowcast stations that operate
in the Extended AM band.

The unit was a Sangean WR-2 which was designed for table-top usage in the
home. It is a robust device, that includes PLL tuning, memory present,
external AMand FM antenna connections. What was most novel about the unit
was it's inclusion of RDS - Radio Data System - for stations in the FM band.
I had never heard of RDS before, and was fascinated to learn about this
intriguing option which provides analogue (and Digital) radio signals with a
complementary data stream which will display text information about the
station your listening to on a digital display dial for radios.

I hesitated to buy the Sangean, but finding it has lead me to investigate a
whole new area of possibilities in radio. A little research on the internet
and at various electrical goods stores around town has revealed that RDS is
not widely implemented by commercial radio operators in Australia. Very few
stores that I visited had devices capable of decoding RDS information. I
guess it's a bit of a catch-22 situation - the big Australian commercial FM
stations hardly use RDS and therefore why should Hi-Fi and car audio shops
stock units that receive RDS signals?

Then I asked myself, is there an AM-Band equivalent for RDS? The answer I
found is YES, but it has a very limited deployment, being only used as far
as I know by the BBC. This AM system is simply called the AM Signalling
System or AMSS for short, and it is capable of providing a similar type and
quantity of data streams as RDS does for FM. You can click the links for
more techncial information on these topics, but I understand that AMSS is
designed for Analogue AM radio, although AM digital radio, such as is
available in Europe on the Digital Radio Mondiale (DRM) system, appears to
have AMSS and RDS functions as standard.

It is sad to me that these data systems for FM and even AM radio have not
been given the attention they should in Australia. I mention this because I
believe these systems add value to radio broadcasting that makes radio
listening much more user friendly for people operating in a TV saturated
age. But much needs to change in our regulatory environment before such
options become viable for church radio stations to implement. Narrowcast
radio stations in Australia are not likely to get permissions to migrate to
a digital platform for some time after the Commercial and Community stations
make their transition.

The Philistine