RDS car radio

[Bob Nelson <raccoonradio@yahoo.com>]

With my car in the body shop for a few days, I'm
driving a rental, and the rental car's stereo has
RDS. First time I've used a stereo with this feature.
This may be old hat to some of you but it's new
to me.

I've noticed most stations don't have the "info" but
some do: For example, when you tune to WODS, the call
letters pop up and when you hit the "Info" button
it says "The Greatest Hits of the 60s and 70s".

On WTKK, it says "FM TALK 96.9" even if you don't
push the Info button. During the noon-3 pm slot,
if you pushed the button you got a promo: "Jay
Severin/ drives you home/ 3-7 pm /FM Talk 96.9"

And on WROR, when you push the button it'll say the
title of the current tune playing and even give you an
advance on what's up next: "Coming up/ Jethro
Tull". Sure enough, "Living in the Past" is the next
song, and when you hit Info again it says "Coming
up/Stevie Wonder", etc.

I think the "Traffic" button scans the dial until it
finds a station which does regular traffic reports...

Does RDS only work with FM? I don't recall it popping
up on any AM stations.

I'm guessing the RDS info is somehow encoded into the
signal, much the way that "closed captions" appear on
TV; when you have a set that has RDS (or captions)
they can pop up if you set it right. I'm guessing
it costs a fair amount of money to do this, which is
why most stations have "NO INFO". 

I would think stations use RDS to help people remember
what station they're tuned to (i.e., the flashing of
"WKLB", "WBOS", etc. will cement the
calls with the frequency in the listener's head);
to keep them tuned (the "Coming Up Next" scrolls),
and for a promo (as with what WTKK was doing in the
example I gave).

I don't know if these are being done, but maybe
soon...

--Weather forecasts ("Today sunny 50s/ Tonite
clouds 30s" etc.)

--(horrors) ads ("Read Dan Shaughnessy/ In today's
Globe"), etc. This would have been perfect back in the
days of one certain roadside advertiser: Had
RDS been around in those days, you would have read:
"Patience, drivers/ Take it slow/ Let the little/
Shavers grow/ Burma-Shave" on the display :)