Co-location of Aux/Backup systems

[mikl73]

What is the point of co-locating your Aux or Backup tx at the same site as your main?

I understand it is cheaper probably but why when a different geographical location would offer much more redundancy

I have always wondered why the bother.

yes times are a bit different with stations set up in stip malls and office parks vs. the old days where they had a building where they could stick a 100ft pole outside (thinking of the old KRNB (KJMS) studio at Tillman & Poplar for example)

 

[radiosaur]

It's playing the odds.

Yes, another site in a different geographical location is the best way, but usually the most expensive. But statistically, it's the transmitter, antenna, or feedline that is most likely to fail so a redundant transmission system on the same tower gives you a high reliability backup for less money. In rare cases like FM100, there is another tower and antenna system on the same property, so they have the added redundancy without the cost. Not too many stations have that luxury.

As a precentage of total outages, structural failures of the tower are rare but do occur...it happened in Memphis to 680 around 1978 or so.

 

[RadeoEngineer]

The most likely cause of failure is a power outage. Most stations have generators that kick in automatically. The second most likely failure is of the transmitter itself, so an aux is usually colocated. It's unusual but it does happen that you could burn up the transmission line or antenna, so in some cases a station might have a backup to those. When you consider flooding or earthquakes there's only so much you can do. Several New Orleans radio and TV stations were brought down by flooding or towers crashing during Katrina. Additional failures can occur with the studio-transmitter link.

It is a huge expense to maintain two completely seperate sites but you can find that in many major markets where the cost of advertising revenue justifies it. It's becoming more common to have a single aux site that can broadcast any one of multiple frequencies, and I know of aux sites that can combine several channels at once.

 

[jboyd]

All points well taken. During the ice storm of 1977, we were without power for three weeks at our 50kw rural site. Astandby on our AM tower saved the day ( or 21 as it was). JBI

 

[radiosaur]

In the 7 years I worked on Union we never had a power outage at the transmitter. They built that site well in the 1940's and 50's - WMC's site has two separate substation feeds with automatic swithover, plus two generators, either of which could run the entire plant.

I have no clue what shape they are in today.

Ah, the good ole days...

 

[FastBytes]

Several New Orleans radio and TV stations were brought down by flooding or towers crashing during Katrina. Additional failures can occur with the studio-transmitter link.

Or in WWL's case the inability to get diesel for the generators (which is why they were on low power for so long after Katrina). The story of how the engineering staff piece mealed the link from the borrowed studios in Baton Rouge back down to the WWL transmitter in New Orleans is still one of my favorite stories.

 

[mikl73]

All points well taken. During the ice storm of 1977, we were without power for three weeks at our 50kw rural site. Astandby on our AM tower saved the day ( or 21 as it was). JBI

the 2 sounds I most remember most from the 79' ice storm are those of WROX's tower falling nearby and the sound of an enormous tree falling accross our driveway and swallowing our front yard as well as part of the neighbors.


I have to say there are so few times I ever turned on 99.7 and there was nothing. I used to keep my alarm clock there just for that reason alone. A few other stations failed to be there during incliment weather over the years resulting in the inability to wake up a a pre-defined time.

 

[Danoinark]

As a precentage of total outages, structural failures of the tower are rare but do occur...it happened in Memphis to 680 around 1978 or so.

Saur, refresh my memory of that? Thanks Dan

 

[KennyBosak]

Since I was on the air when it happened, I can provide some details:

It was indeed 1978, and I'm pretty sure it was a Sunday morning.

On a set schedule -- every three hours I think -- we were required to take transmitter readings and log them. Since WMPS had a five-tower array, we had to not just check things like plate volts and plate amps, but the phase of each tower to maintain the integrity of the pattern.

I routinely grabbed the clipboard to take readings. All towers were fine ... except one. For that tower, the needle on the meter was way off from what would be expected, and it was also moving slightly up and down erratically.

I immediately called our chief engineer, the late Robert E. Knight. We knew something strange was going on, but we had no idea of the enormity of the situation.

Robert went to the transmitter site and discovered the unimaginable: One of the five towers was a crumpled mass of steel on the ground. As fate would have it, the fallen tower was also the one that carried K-97's antenna.

No one witnessed the tower falling, but they were pretty certain it happened this way: A guy wire attached to the top section of the tower failed, causing that section to fall. As it fell, so the theory goes, it took out more guy wires on the way down, resulting in the catastrophic collapse of the entire tower.

I believed that K-97 was moved to one of the other towers while a replacement was erected.

Maybe we played "Please Help Me, I'm Falling" by Janie Fricke one too many times.

 

[MikeBratton]

Maybe we played "Please Help Me, I'm Falling" by Janie Fricke one too many times.

Thank you, Kenny. Now I have that song stuck in my head.

And it couldn't have been Webb Pierce's rendition. Or Conway Twitty's. Or Dolly Parton's.

Nooooooo, it had to be Janie Fricke...