Just an example of interference from this wretched IBOC, listening
to Imus on WFAN 660 NYC from Central Ohio, having nulled away the local
WXIC 660 in Waverly Ohio, and WMIC 660 in Sandusky MI

http://rhhardin.home.mindspring.com/imuscut.iboc.ram (25 seconds)

not a sterling moment in Imus but, at 22 seconds in, WSCR _670_ Chicago
flips on IBOC for the morning at 8:15am Eastern, and that's the end of
Imus on _660_.

(The glitch at 17 before that is switching the receiver from DSB to LSB, to get
rid of the 4 Hz wobble from WXIC being 4 Hz high in frequency; me being unaware
of what is coming down the tunnel in 5 seconds.)

Not that it's news to anybody, but just a recorded example at hand.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

On Sat, 14 Jan 2006 13:53:29 GMT, Ron Hardin
wrote:

Just an example of interference from this wretched IBOC, listening
to Imus on WFAN 660 NYC from Central Ohio, having nulled away the local
WXIC 660 in Waverly Ohio, and WMIC 660 in Sandusky MI

http://rhhardin.home.mindspring.com/imuscut.iboc.ram (25 seconds)

not a sterling moment in Imus but, at 22 seconds in, WSCR _670_ Chicago
flips on IBOC for the morning at 8:15am Eastern, and that's the end of
Imus on _660_.

(The glitch at 17 before that is switching the receiver from DSB to LSB, to get
rid of the 4 Hz wobble from WXIC being 4 Hz high in frequency; me being unaware
of what is coming down the tunnel in 5 seconds.)

Not that it's news to anybody, but just a recorded example at hand.
Same here in Los Angeles. KTLK 1150 is completely buried in IBOC hash
from KSL Salt Lake City 1160 every morning. They should wait until
everyone is on Daytime power before allowing that crap be turned on.

Ron Hardin wrote:
Just an example of interference from this wretched IBOC, listening
to Imus on WFAN 660 NYC from Central Ohio, having nulled away the local
WXIC 660 in Waverly Ohio, and WMIC 660 in Sandusky MI

http://rhhardin.home.mindspring.com/imuscut.iboc.ram (25 seconds)

not a sterling moment in Imus but, at 22 seconds in, WSCR _670_ Chicago
flips on IBOC for the morning at 8:15am Eastern, and that's the end of
Imus on _660_.

(The glitch at 17 before that is switching the receiver from DSB to LSB, to get
rid of the 4 Hz wobble from WXIC being 4 Hz high in frequency; me being unaware
of what is coming down the tunnel in 5 seconds.)

Not that it's news to anybody, but just a recorded example at hand.

Of course, the official Ibiquity line is:

- You can't get WFAN in Ohio.
- You ought to be listening to your *local* stations.
- Yeah, the program (/format) you want to listen to isn't on any of your
locals, but the John Doofus Talk Extravaganza is; isn't that just as good?
- Oh, John Doofus isn't the same thing - you really want to listen to
*Imus*? He'll be on one of the IBOC subchannels of one of your local
FMs. Someday. Maybe.

Some advance, huh?

I do think IBOC will eventually sell millions of digital radios.

Millions of Sirius and XM digital radios.
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

"Ron Hardin" wrote in message
...

[snip]


not a sterling moment in Imus but, at 22 seconds in, WSCR _670_ Chicago
flips on IBOC for the morning at 8:15am Eastern, and that's the end of
Imus on _660_.


[snip]

For what it's worth, WSCR's CBS owned sister station, WBBM 780, still hasn't
resumed IBOC broadcasting. The upper sideband interfered with O'Hare
airport's 800 kHz Traffic Information Station (actually a parking
information station). I don't know if the interference has anything to do
with suspending the IBOC broadcasting from WBBM.

During the time both stations were testing, there were times in which both
WBBM and WSCR were both running IBOC at the same time and times in which
they were running IBOC alternately. I didn't think about it much at the
time, but I now wonder if they were trying to get both IBOC channels
broadcasting off the same antenna.

Frank Dresser

I can't understand why anybody would want to listen to imus the an.s
anyway.I have better sense that to listen to that crap.
cuhulin

"D Peter Maus" wrote in message
...
Frank Dresser wrote:

During the time both stations were testing, there were times in which
both
WBBM and WSCR were both running IBOC at the same time and times in which
they were running IBOC alternately. I didn't think about it much at the
time, but I now wonder if they were trying to get both IBOC channels
broadcasting off the same antenna.

Frank Dresser



Not likely. IBOC requires a particularly broad, even spectrum off the
antenna. AM antennae, though broader than comm antennae, are still
frequency specific. Stations of such disparate frequencies would be hard
pressed to meet the flat response required by IBOC on both stations if
combined into a single antenna.


That's not to say it can't be done. But the cost of doing so, and for
experimentation at that, would be far outside BlackRock's capital budget
caps. Not to mention the potential power/pattern repercussions once the CP
was filed. Modification of existing physical plant could open the door to
counter filings, potential protracted legal battles, and even challenges
to existing licenses/operating parameters.

As boneheaded as CBS Radio has been around here in the last 8 months,
even THEY aren't that stupid.

Then, again.........



Large numbers of stations in metro areas are already sharing antenna
systems. Most have done this either in order to decrease the number of
physical plants or to simply save on leasing of or purchase of land for
antenna systems. The towers themselves are only truly narrowband at
resonance. When two (or even more) transmitters share a system, at most one
of them will be at resonance. As far as the matching hardware, it can be
engineered to be as broad as it needs to be.

"Brenda Ann" wrote in message
...


Large numbers of stations in metro areas are already sharing antenna
systems.

When AMs share antenna systems, most are non-directional. A number of cases
exist where a directional AM share a single tower with an non-D station,
like 1390 and 1680 in Chicago. 1390 is directional, but the X Band staiton
just uses one tower. The efficiency of doing this vs. cost is good.

Not too many shared directionals exist, as the system has to be able to
create the appropriate pattern for each station, and that is a relationship
of phase and current and wavelength spacing of the towers.

When directionals share, it is in cases lik KTLK and KTNQ in LA, where the
towers could be made to work for two fairly similar systems. This cost over
$1 million to do, just for the tuning units and rejection networks... not
including towers and transmitters and buildings. It took the best DA guy in
the US, Ron Rackley, over a month to tune it.

The only case where share DAs by two directinal stations makes sense is
where there simply is no land available. The cost and maintenance is very
high, and it is not done to save money.

Most have done this either in order to decrease the number of physical
plants or to simply save on leasing of or purchase of land for antenna
systems. The towers themselves are only truly narrowband at resonance.

Actually, this has little to do with the tower. While a wider face tower is
easier to broadband, most of the bandwidth at a particular frequency has to
do with the Q of the tuning circuits in the system. In earlier times, higher
Q systems were designed as they were chaper, easy to adjust, etc.

When two stations tune to a tower, each has a tuning system (ATU or antenna
tuning unit) that matches the line impedance to the tower impedance. Then,
there are rejection networks to let each station feed into the tower, but
not allowing the RF from one to get back into the trnsmitter of the other.

As long as the system is broadband, the signal will be broadband.

When two (or even more) transmitters share a system, at most one of them
will be at resonance. As far as the matching hardware, it can be
engineered to be as broad as it needs to be.

Very few towers are a perfect 50 ohms with no reactance. So all require
matching. What changes, based on tower height, is the efficiency of the
radiator and the angle of radiation (each of these being about the same
thing) but I have seen 1/8 wave towers tuned for great bandwidth with high Q
circuits. In fact, I had an 8th waver at 570 that I diplexed a station at
805 into, and we had both sounding great because we made the bandwidth at
each frequency very good at up to plus and minus 15 kHz, and the filter nets
were very specific to each frequency against the other.

Hi Frank,

I didn't realize you were in the Chicago area. Now, if only WTMJ would turn
off their IBOC signal. They totally wipe out 610 and 630 up here in
Waukegan.

Pete
"Frank Dresser" wrote in message
...

"Ron Hardin" wrote in message
...

[snip]


not a sterling moment in Imus but, at 22 seconds in, WSCR _670_ Chicago
flips on IBOC for the morning at 8:15am Eastern, and that's the end of
Imus on _660_.


[snip]

For what it's worth, WSCR's CBS owned sister station, WBBM 780, still
hasn't
resumed IBOC broadcasting. The upper sideband interfered with O'Hare
airport's 800 kHz Traffic Information Station (actually a parking
information station). I don't know if the interference has anything to do
with suspending the IBOC broadcasting from WBBM.

During the time both stations were testing, there were times in which both
WBBM and WSCR were both running IBOC at the same time and times in which
they were running IBOC alternately. I didn't think about it much at the
time, but I now wonder if they were trying to get both IBOC channels
broadcasting off the same antenna.

Frank Dresser

In article ,
"Brenda Ann" wrote:

"D Peter Maus" wrote in message
...
Frank Dresser wrote:

During the time both stations were testing, there were times in which
both
WBBM and WSCR were both running IBOC at the same time and times in which
they were running IBOC alternately. I didn't think about it much at the
time, but I now wonder if they were trying to get both IBOC channels
broadcasting off the same antenna.

Frank Dresser



Not likely. IBOC requires a particularly broad, even spectrum off the
antenna. AM antennae, though broader than comm antennae, are still
frequency specific. Stations of such disparate frequencies would be hard
pressed to meet the flat response required by IBOC on both stations if
combined into a single antenna.


That's not to say it can't be done. But the cost of doing so, and for
experimentation at that, would be far outside BlackRock's capital budget
caps. Not to mention the potential power/pattern repercussions once the CP
was filed. Modification of existing physical plant could open the door to
counter filings, potential protracted legal battles, and even challenges
to existing licenses/operating parameters.

As boneheaded as CBS Radio has been around here in the last 8 months,
even THEY aren't that stupid.

Then, again.........



Large numbers of stations in metro areas are already sharing antenna
systems. Most have done this either in order to decrease the number of
physical plants or to simply save on leasing of or purchase of land for
antenna systems. The towers themselves are only truly narrowband at
resonance. When two (or even more) transmitters share a system, at most one
of them will be at resonance. As far as the matching hardware, it can be
engineered to be as broad as it needs to be.

Antennas can have a broader response by increasing the diameter of the
vertical radiator. This can be done by running at least three wires
around the tower 120 degrees apart with a ring connecting them together
top and bottom minimum. This is much cheaper than constructing a larger
diameter tower. Increasing radiator diameter to broaden the response is
a general rule that can be applied to most antennas.

--
Telamon
Ventura, California

Telamon wrote:
In article ,
"Brenda Ann" wrote:

"D Peter Maus" wrote in message
...
Frank Dresser wrote:

During the time both stations were testing, there were times in which
both
WBBM and WSCR were both running IBOC at the same time and times in which
they were running IBOC alternately. I didn't think about it much at the
time, but I now wonder if they were trying to get both IBOC channels
broadcasting off the same antenna.

Frank Dresser


Not likely. IBOC requires a particularly broad, even spectrum off the
antenna. AM antennae, though broader than comm antennae, are still
frequency specific. Stations of such disparate frequencies would be hard
pressed to meet the flat response required by IBOC on both stations if
combined into a single antenna.


That's not to say it can't be done. But the cost of doing so, and for
experimentation at that, would be far outside BlackRock's capital budget
caps. Not to mention the potential power/pattern repercussions once the CP
was filed. Modification of existing physical plant could open the door to
counter filings, potential protracted legal battles, and even challenges
to existing licenses/operating parameters.

As boneheaded as CBS Radio has been around here in the last 8 months,
even THEY aren't that stupid.

Then, again.........


Large numbers of stations in metro areas are already sharing antenna
systems. Most have done this either in order to decrease the number of
physical plants or to simply save on leasing of or purchase of land for
antenna systems. The towers themselves are only truly narrowband at
resonance. When two (or even more) transmitters share a system, at most one
of them will be at resonance. As far as the matching hardware, it can be
engineered to be as broad as it needs to be.

Antennas can have a broader response by increasing the diameter of the
vertical radiator. This can be done by running at least three wires
around the tower 120 degrees apart with a ring connecting them together
top and bottom minimum. This is much cheaper than constructing a larger
diameter tower. Increasing radiator diameter to broaden the response is
a general rule that can be applied to most antennas.



FM systems share antennae all the time. AM's though, not so much. To
materially change the system, would require a CP which would open the
installation to challenge. This is particularly true of modifying
existing AM's to share common antennnae. Even omni's.