Due to interference concerns, CC will not install AM-HD in Hawaii

[PocketRadio]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

 

[PocketRadio]

"List of broadcast stations owned by Clear Channel"

http://en.wikipedia.org/wiki/List_of_broadcast_stations_owned_by_Clear_Channel

KSSK AM 590
KHVH AM 830
KHBZ AM 990

Interesting - at this spacing, "they would all trip over each other".

Here is a list of all AM stations in Hawaii:

"BIG ISLAND RADIO DIAL"

620 KIPA
670 KPUA
790 KKON
850 KHLO
1060 KHBC
1640 URH

http://www.hawaiiradiotv.com/BigIsleRadio.html#AM-Dial

 

[radiopilot]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

Too bad the mainland AM-HD won't admit to interference and tripping over each other, it's interesting that they won't transmit in AM...

What is atrocious is that they believe sales of tabletop HD radios that cost about $300, (less after a mail-in rebate) is going to be a simple endeavour, go to Radio Shack or Circuit City, (--but as broadcasters are fond of pointing out, there are no subscription fees as there are with satellite radio), another excuse to make people believe they are getting something satelite dosen't offer for those WANTING to pay the satelite fees.

Radiopilot

 

[R.F. Burns]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

Three AM's triplexed Oh My Goodness!! Three count em' three!!! Wow. Uhhh, why will the three stations trip over each other on the island of Hawaii, when we have 2, 50 KW class 1 A, Non D's diplexing 2 HD signals into the same stick with no problem and FM's? How about Empire in NYC where there are at least 12 FM HD stations co-located on the same tower and they all work well together? Are the laws of physics different in our crowded RF market then they are in Hawaii?

 

[PocketRadio]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

Too bad the mainland AM-HD won't admit to interference and tripping over each other, it's interesting that they won't transmit in AM...

What is atrocious is that they believe sales of tabletop HD radios that cost about $300, (less after a mail-in rebate) is going to be a simple endeavour, go to Radio Shack or Circuit City, (--but as broadcasters are fond of pointing out, there are no subscription fees as there are with satellite radio), another excuse to make people believe they are getting something satelite dosen't offer for those WANTING to pay the satelite fees.

Radiopilot

Interesting, that CC owned KHBZ AM 990 is not near any other AM stations in Hawaii - perhaps, they are concerned with interference to an AM station on the Mainland, due to nighttime skywave propagation ?

 

[R.F. Burns]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

Too bad the mainland AM-HD won't admit to interference and tripping over each other, it's interesting that they won't transmit in AM...

What is atrocious is that they believe sales of tabletop HD radios that cost about $300, (less after a mail-in rebate) is going to be a simple endeavour, go to Radio Shack or Circuit City, (--but as broadcasters are fond of pointing out, there are no subscription fees as there are with satellite radio), another excuse to make people believe they are getting something satelite dosen't offer for those WANTING to pay the satelite fees.

Radiopilot

Interesting, that CC owned KHBZ AM 990 is not near any other AM stations in Hawaii - perhaps, they are concerned with interference to an AM station on the Mainland, due to nighttime skywave propagation ?

This is very curious considering that there are no high powered stations in Honolulu. They are all Non D and at most they are 10K. In NYC alone in the very tight eastern corridor we have 9, 50 KW stations operating. We have 4, 50 K IBOCs on 660, 710, 770 and 880 Khz. We also had IBOC AM's on 820, 1280 and at one time even 930 & 1480 for test purposes.
It's not been a problem for suburban listeners.

 

[IBOCRocks]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

It very well could be a bandwidth issue with their antenna system. As has been posted here, there are plenty of cities that have closer spaced AM's running HD without issue.

Much adieu about nothing, I'm afraid.

 

[davideduardo]

It very well could be a bandwidth issue with their antenna system. As has been posted here, there are plenty of cities that have closer spaced AM's running HD without issue.

Much adieu about nothing, I'm afraid.

The issue is that, unlike most mainland stations, just about every AM in Hawiii is non-directional and there are 3 to 4 diplexed on each tower. The designs for the rejection networks in such installs are very sharp, and already restrict bandwidth. They can't be broadbanded...

 

[davideduardo]

This is very curious considering that there are no high powered stations in Honolulu. They are all Non D and at most they are 10K. In NYC alone in the very tight eastern corridor we have 9, 50 KW stations operating. We have 4, 50 K IBOCs on 660, 710, 770 and 880 Khz. We also had IBOC AM's on 820, 1280 and at one time even 930 & 1480 for test purposes.
It's not been a problem for suburban listeners.

When you have 4 stations on the same tower, as is generally the case in Honolulu, the bandwith for each signal on the tower is very narrow and not necessarily flat. I believe one tower has 5 stations on it.

 

[davideduardo]

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

Very few mainland AMs are diplexed, let alone triplexed or quadraplexed. The more AMs on each tower, the tighter the bandwidth on each is, and the highjer the Q of the passband designe for the ATU and the rejection network. Broadbanding a triplexed system is quite a feat, and probably not worthwhile in that market, which has a really high FM usage.

There is no manland parallel to the triplexing and beyond used in Hawaii, where land cost, zoning, etc. make having single stations on a tower nearly impossible on Oahu.

 

[clouseau]

"HD radio broadcasting hits Hawaii with Star 101.9"

"Clear Channel's Hawaii AM stations won't go HD, as their mainland counterparts have. We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said."

http://starbulletin.com/2007/04/03/business/engle.html

How interesting - Clear Channel is admitting to interference with AM-HD. What about Mainland AM-HDs - aren't AMs crowded enough to cause interference ? And, this is progress ?

This is REALLY funny. I wondered how this would be different on the Island as opposed to the mainland. So I went to the story to get details. The two sentences posted above represent ALL of the content about AM HD in the story. Therefore, it's not indicative of an underlying fact. It's the whole story. And the whole story is...

"We have so many transmitters multiplexed here, meaning three AM transmitters in the same location ... they would all trip over each other, he said." The reason is NOT as Pocket has stated. It has to do with transmitter SITES. And the extensive "Filtering" thatis required to Diplex and Triplex AM's. The following quote..

How interesting - Clear Channel is admitting to interference with AM-HD.

is a complete fabrication. It's just not so. IT WAS MADE UP IN THE MIND OF THE POSTER.

Later on, the poster speculated, why they would interfere with each other. The poster posted a list of stations. Can't figure it out. That's because that's not what they're talking about.

Multiplexing transmitters require a LOT more equipment than just "Transmitting." RF Burns could explain this better than me, but here goes.

Let's say we have 4 towers. Two towers directional on 560, 4 towers on 790 and 1 tower on 1230. (I Just made this up, but it is a fairly decent representation of a triplex)

In additional to the transmitting equipment you would have at a single site, you would need a filters for 560 both of the non 560 towers. You would need 3 1230 filters on the non 1230 towers etc..etc... 12 of the beasties. and they are already there. To vary the bandwidth of each of them (and depending on how they are built - replace them) it would be VERY expensive. Also, there is a good chance some of these station which are diplexed are NOT owned by Clear Channel (Even if CC owns the site.) This would involve a good deal of down time. I'm not sure I'd be real happy with them taking my sation down for a few days while they get everything back up.

It has NOTHING to do with the "Interference" that the ANTI HD folks are so DESPERATLY trumpeting/.

Clouseau

 

[IBOCRocks]

700WLW...busted again.

 

[davideduardo]

Multiplexing transmitters require a LOT more equipment than just "Transmitting." RF Burns could explain this better than me, but here goes.

Absolutely.

Hawaii has no directionals since KAIM dropped power and moved... all on Oahu use one tower for multiple transmitters.

Each station has to tune to the tower for it's frequency, and reject the other frequencies and, generally, all other frequencies tuned to the tower. This means passing the fundamental and rejecting the others so RF does not get back into the transmitter from the other stations.

The result is that the bandwith for the fundamental is narrower than a single staiton tower, and that even limits response for analog to some extent.

Since the tower is and can not be the "right" wavelength for every station, the reactance will also be high, and different on each sideband. This further complicates any system that requires high and low sideband symetry or balance.

 

[Mike Walker]

Yet another thread retrieved in a most unsanitary manner from deep within the bowels of it's originiator.

 

[R.F. Burns]

Multiplexing transmitters require a LOT more equipment than just "Transmitting." RF Burns could explain this better than me, but here goes.

Absolutely.

Hawaii has no directionals since KAIM dropped power and moved... all on Oahu use one tower for multiple transmitters.

Each station has to tune to the tower for it's frequency, and reject the other frequencies and, generally, all other frequencies tuned to the tower. This means passing the fundamental and rejecting the others so RF does not get back into the transmitter from the other stations.

The result is that the bandwith for the fundamental is narrower than a single staiton tower, and that even limits response for analog to some extent.

Since the tower is and can not be the "right" wavelength for every station, the reactance will also be high, and different on each sideband. This further complicates any system that requires high and low sideband symetry or balance.

How are they doing it with the two 50 K stations in NY. One on 660 and the other on 880 on a single stick.

 

[davideduardo]

How are they doing it with the two 50 K stations in NY. One on 660 and the other on 880 on a single stick.

Diplexing is not difficult to achieve, but making the staitons work as well as with a single tower presents challenges.

660 and 880 are both what were the old 1A clears, and require a half wave tower for compliance. Since there are 220 kHz separation, the ability to broadband a bit is possible as the separation is decent. And it looks like 660 is just under a half wave tower and 880 is just about a 5/8 wave, based on the mast and the top loading.

Given the cost of land, diplexing is often a very significant alternative. It's less expensive than land, but increases costs considerably.

 

[R.F. Burns]

How are they doing it with the two 50 K stations in NY. One on 660 and the other on 880 on a single stick.

Diplexing is not difficult to achieve, but making the staitons work as well as with a single tower presents challenges.

660 and 880 are both what were the old 1A clears, and require a half wave tower for compliance. Since there are 220 kHz separation, the ability to broadband a bit is possible as the separation is decent. And it looks like 660 is just under a half wave tower and 880 is just about a 5/8 wave, based on the mast and the top loading.

Given the cost of land, diplexing is often a very significant alternative. It's less expensive than land, but increases costs considerably.

Well if CC owns the three stations diplexing into a single tower I wonder why they don't try putting a exciter on at least one of the stations for which the tower is optomized.

 

[davideduardo]

How are they doing it with the two 50 K stations in NY. One on 660 and the other on 880 on a single stick.

Diplexing is not difficult to achieve, but making the staitons work as well as with a single tower presents challenges.

660 and 880 are both what were the old 1A clears, and require a half wave tower for compliance. Since there are 220 kHz separation, the ability to broadband a bit is possible as the separation is decent. And it looks like 660 is just under a half wave tower and 880 is just about a 5/8 wave, based on the mast and the top loading.

Given the cost of land, diplexing is often a very significant alternative. It's less expensive than land, but increases costs considerably.

Well if CC owns the three stations diplexing into a single tower I wonder why they don't try putting a exciter on at least one of the stations for which the tower is optomized.

I suspect it is an issue of both the tighntess of the passband at that frequency (most of these were designed for very high Q and are not broadband) and the fact that the reactive component is not symetrical, which would make it hard to put HD on it.

 

[tomservo]

I thought the big part of the story was that HD debuted on April Fool's Day - *bada-bing!*

Sorry, I couldn't resist. ;D