Transmission line failure knocks off 4 stations in Boston

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NECRAT
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Transmission line failure knocks off 4 stations in Boston

Post by NECRAT »

Sunday night around 7:35pm, a failure of the main transmission line going to the "upper master" antenna taking off four stations, WBZ-TV (D-30), WCVB (D-20), WSBK (D-39) and WGBX (D-43). WGBH-TV, which uses the lower master antenna was not affected. The 1300 tower had a failure on Sunday, which as of this morning, remains off the air.

The tower, according to media reports, has two feedlines going up the tower to the antenna system, a main and a standby. The tower crew ascended the tower yesterday to switch over the feedlines but apparently did not have the correct parts, which are going to have to be shipped from Dielectric.

WCVB maintains a small backup about 2/3 of the way up the tower, and was able to return to the air, using a much reduced facility.

There is no word as to when the stations will return, or if CBS decides to look into auxiliary facilities for their two stations , which remain off.
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BingNYEng
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Re: Transmission line failure knocks off 4 stations in Bosto

Post by BingNYEng »

A good lesson to check to make sure you have the ability to use your standby equipment.

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Re: Transmission line failure knocks off 4 stations in Bosto

Post by NECRAT »

This has become a much bigger issue.

A little background on the antenna. Here are some pictures and technical info on the tower

This 1300' tower in Needham is topped with a "stacked" UHF antenna.
The upper antenna has WBZ-TV (Digital 30), WCVB (Digital 20), WSBK (Digital 39) and WGBX (Digital 43)
The lower antenna has WGBH (Digital 19) and had WGBX-TV (Analog 44).
WCVB maintained a small backup antenna 616' on the tower.

At some point on Sunday night, the power divider which feeds the upper antenna failed. During the day today, the tower crew re-rigged the RF feeds on the tower, and moved the master combiner into the lower UHF antenna. (WGBH-TV was moved from the lower UHF to the WCVB standby on the tower).

There is conflicting information as to the location of the power divider, I've heard it is located within the main antenna and at the base of the dual antenna system. The discussions now are on the repair of the power divider and the possiblity of the antenna needing to be rigged down to be repaired as well.
The stations are in the process of installing a "master backup" antenna system for the stations to go to, so that work can be done on the master antenna safely.
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NECRAT
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Re: Transmission line failure knocks off 4 stations in Bosto

Post by NECRAT »

UPDATE

The scenaro has gone from Bad to worse. The failure in the upper half of the Master Antenna is both with the power divider and the actual antenna has suffered damage.
In an online posting, published by WGBH-TV, it stated the following:
On April 8 there was a major failure in the combined transmission antenna at the Needham tower site that affected WGBH 2, WGBX 44—our multicast services World, Create, and Kids—as well as WBZ, WCVB, and WSBK, which all share the transmitter. Crews were immediately dispatched to the tower and they made emergency repairs, which allowed these stations to return to the air, though at a diminished broadcast coverage area for both Channel 44 and Channel 2 and for some cable subscribers.

As of Wednesday, April 18, the upper antenna must be removed due to the extensive damage to the components. The parts needed must be manufactured, installed, and then tested for a complete repair to be accomplished, which may take up to a month.

Here is a picture of the above mentioned antenna,
Image
(Which resides at this page on my site).
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Re: Transmission line failure knocks off 4 stations in Bosto

Post by K9EZ »

It is astounding to me that a market of this size, has MAJOR stations without any back up antenna or plan. Has engineering really dropped to such a level??
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Deep Thought
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Re: Transmission line failure knocks off 4 stations in Bosto

Post by Deep Thought »

K9EZ wrote:Has engineering really dropped to such a level??
No, but management and ownership has. OTA TV sold its soul for cable carriage.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

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Re: Transmission line failure knocks off 4 stations in Bosto

Post by rockmanac »

Deep Thought wrote:
K9EZ wrote:Has engineering really dropped to such a level??
No, but management and ownership has. OTA TV sold its soul for cable carriage.
We have backups to the backup in the control room (I'm not joking!) I however, don't think we have a backup for the antenna....though we do have 2 repeaters....though they don't cover the territory that the main signal does.
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Re: Transmission line failure knocks off 4 stations in Bosto

Post by w4cl »

We have two towers with we can transmit from. The aux isn't full power, but we can hit all the cable headends and reach the major metro areas with it. The owners would LOVE to get rid of the aux tower. To them it is just higher insurance premiums and higher maintenance costs on the bottom line. We have have successfully fought them off several years. Just three months ago when the voltage regulator by pass switch at the main site went up in smoke (480 to ground isn't pretty) and kicked off the main breaker to the building, that aux tower saved our bacon. Instead of being off air for several hours, we were off air a total of 6 minutes.

"... from my cold dead hands."

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