On Thu, 02 Aug 2007 08:37:01 -0700, laura halliday wrote:
We have nationwide radio networks in Canada from the CBC,
but don't use RDS. Too many AM transmitters to make it work;
probably other issues too.

Some CBC stations did run RDS for awhile, but I don't recall any of them
using the AF field. (but I only ever saw RDS on the ones that made it
into Tennessee via sporadic-E) I understand they were somehow used in
conjunction with a data-paging scheme, and when that scheme went bust many
of the encoders were shut off.

There really aren't that many AM transmitters left -- offhand I can think
of St. John's (NL), Windsor, Winnipeg, Regina (Watrous), Edmonton,
Calgary, and Vancouver. The four on the Prairies all have FM relays
within the city centre, so I'd imagine the majority of the audience is
listening on FM even there. Apparently you *can* specify an AM frequency
in the AF field - I've seen it done - though while you can direct a
receiver *from* FM *to* AM you obviously can't do it the other way around.

We played with DAB for a while on L band, but have quietly walked away
from it. There's just one multiplex still on the air here in Vancouver.

Yeah, that's unfortunate. Your system provides more choice, better
quality, and no interference to the existing analog service. I suppose
the lack of economies of scale with the U.S. market doomed it. The CRTC
is now considering allowing our IBOC system. (and the CBC has tested it in
Toronto and Peterborough) They seem VERY leery of authorizing it on AM
though.

I've often thought wide band FM ham radio (e.g. 10 GHz) could benefit
from RDS ("VE7LDH 10.2 GHz QTHR QSL via buro").

Interesting idea.

Reportedly some new iPod transmitters include RDS encoders (?!) (along
with some kind of scheme for reading the song title/artist data out of the
iPod) so apparently encoders are available at consumer-practical prices.
The standard is no secret, so someone adequately skilled would probably
have little trouble building one.

On Aug 2, 9:54 am, Doug Smith W9WI wrote:

There really aren't that many AM transmitters left -- offhand I can think
of St. John's (NL), Windsor, Winnipeg, Regina (Watrous), Edmonton,
Calgary, and Vancouver. The four on the Prairies all have FM relays
within the city centre, so I'd imagine the majority of the audience is
listening on FM even there. Apparently you *can* specify an AM frequency
in the AF field - I've seen it done - though while you can direct a
receiver *from* FM *to* AM you obviously can't do it the other way around.

There are still Radio 1 repeaters on AM in small towns. All the new
stuff is on FM. There was a major stink a few years ago when CBC
Toronto traded in their old AM frequency for the last available FM
frequency in the Toronto/Hamilton/Buffalo area.

We played with DAB for a while on L band, but have quietly walked away
from it. There's just one multiplex still on the air here in Vancouver.

Yeah, that's unfortunate. Your system provides more choice, better
quality, and no interference to the existing analog service. I suppose
the lack of economies of scale with the U.S. market doomed it. The CRTC
is now considering allowing our IBOC system. (and the CBC has tested it in
Toronto and Peterborough) They seem VERY leery of authorizing it on AM
though.

The main push for digital radio here is now Sirius. We were using
totally standard Eureka 147, albeit at a different frequency than
Europe. It works, but suffers from spotty coverage due to lousy
transmitters - if they had continued to build it out, it might work
better. But the one piddly little transmitter left on Mount Seymour
gives surprisingly good coverage. I bought a little DAB radio at
Radio Shack, and it works just fine.

One issue that has been raised as a stumbling block to DAB in
the Americas is that multiplexes require stations to share a
frequency - stations that are otherwise competitors.

The only remaining multiplex here has the three CBC English
networks and the two CBC French networks. The other multi-
plexes, before they were turned down, had stations owned by
the same companies on them (Corus, CHUM).

We (hams) have oodles of bandwidth in our microwave
bands. We could play with this stuff too.

Laura Halliday VE7LDH "Non sequitur. Your ACKS are
Grid: CN89mg uncoordinated."
ICBM: 49 16.05 N 122 56.92 W - Nomad the Network Engineer

On Thu, 02 Aug 2007 13:46:40 -0700, laura halliday wrote:
There are still Radio 1 repeaters on AM in small towns. All the new
stuff is on FM. There was a major stink a few years ago when CBC
Toronto traded in their old AM frequency for the last available FM
frequency in the Toronto/Hamilton/Buffalo area.

Absolutely, though those are disappearing too. I saw one in Iron Bridge,
Ont. two years ago - a wire about 15m long strung between two phone poles,
a surprisingly stout building housing the 40-watt transmitter. Maybe that
was Premiere Chaine, not Radio 1? I forget...

One issue that has been raised as a stumbling block to DAB in the
Americas is that multiplexes require stations to share a frequency -
stations that are otherwise competitors.

Here in the States duopolies have led to the situation where one owner
would be able to use an entire multiplex pretty easily. I think the real
stumbling block here was that Eureka would give Acme Radiocorp's 250-watt
daytime-only AM station exactly the same coverage (and full-quality audio)
as XYZ Broadcasting's 100kw FM. XYZ would rather not have the
competition.

The only remaining multiplex here has the three CBC English networks and
the two CBC French networks. The other multi- plexes, before they were
turned down, had stations owned by the same companies on them (Corus,
CHUM).

Radio 3 is on the air on DAB?

We (hams) have oodles of bandwidth in our microwave bands. We could play
with this stuff too.

German hams have been messing with amateur digital TV - their board
supports our ATSC standard too.