Old AM Broadcast Towers Get a New Life

Esther Schindler shares an article from Hewlett Packard Enterprise: Video may have killed the radio star, but other media certainly make old AM radio towers superfluous... maybe. "As once-loyal listeners tune away, most AM stations are barely holding onto life, slashing staff and budgets as deeply as they can while struggling to find a return to profitability," reports HPE. "Once upon a time, having a broadcast license of any kind was like having a permit to print money. In today's world, that's no longer true." But, with some 10,000 AM broadcast towers in the United States stretching high into the sky, there may be an opportunity for wireless carriers who don't want to argue with community opposition from neighborhoods where residents don't want yet another cell tower. The amount of money an AM station owner can pocket by sharing its tower with a wireless partner varies widely, depending on the tower's location, height, and several other factors. But it's certainly more income -- and a way to keep "old" technology from becoming obsolete. "Using an AM tower, which has very often been in place for many years, avoids many zoning and other permitting issues, versus going in and creating a new site for a tower," Behr explains. He says local residents, businesses, and officials rarely complain about an AM broadcast tower that suddenly begins serving as a cell site. "That tower was there before they were, and it doesn't bother them," Lawrence Behr, CEO of Greenville, North Carolina-based LBA Group, says. "Hanging a few things on it is rarely controversial, so that's a real good thing for AMs."

Comments

Radiation

[dwywit]

Honest question - isn't it necessary to de-energise the transmitter before technicians can climb the tower to install or maintain hardware? Presumably it happens in the graveyard shift. The ERP right at the tower must be quite high.

Re:Radiation

[Known Nutter]

You can be on the tower, or you can be on the ground, but you can't be on both. It's not the potential that kills, it's becoming a circuit path. Birds roosting on power distribution lines, which as a general rule are not insulated, don't die due to that fact.

That's not how any of this works.

First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

The parent poster was concerned with worker safety when exposed to radio frequency energy.

https://transition.fcc.gov/Bur...

After performing the required calculations and determining it is safe to work at x distance from the transmitter antenna, workers will typically wear a personal RF monitor to measure exposure.

Re:Radiation

[DRJlaw]

That's not how any of this works.

First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

Please, tell me how AM broadcasting works (first and last visible paragraphs of section 5.5.5.2). Because for the majority of AM transmission towers you are dead wrong - literallty.

"Most AM radio towers are series fed (end fed at the bottom) and have a ceramic insulator at the base. A few smaller ones are shunt fed about 20 feet up the tower and are grounded at the base, and a variation are metal poles grounded and have wires insulated from the pole as vertical radiators."

Up to 50,000 watts says that the primary concern is electric shock. A secondary concern is RF exposure.

Try Googling AM radio, maintenance, and "hot tower" before you lecture about areas that you plainly lack experience in.

Re:Radiation

[religionofpeas]

First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

https://www.youtube.com/watch?...

Re:Radiation

[petecarlson]

You can be on the tower, or you can be on the ground, but you can't be on both. It's not the potential that kills, it's becoming a circuit path. Birds roosting on power distribution lines, which as a general rule are not insulated, don't die due to that fact.

That's not how any of this works.
  First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.
The parent poster was concerned with worker safety when exposed to radio frequency energy.
https://transition.fcc.gov/Bur...

After performing the required calculations and determining it is safe to work at x distance from the transmitter antenna, workers will typically wear a personal RF monitor to measure exposure.

As others have mentioned, you are pretty wrong here. The vast majority of AM towers are the radiators and the ground is the ground plane. Between them sits a huge isolator which is generally ceramic. If you stand on the ground and touch the tower above the isolator you will get burned or dead.

This makes colocating on an AM tower a PITA as you can't just run a conductor up the tower without a transformer. There are ways to do it, my favorite being to get power off of the tower lighting circuit to power a tower mounted enclosure and then running fiber off of the tower if I need to come off of it.

If AM radio is dying, it is because of the

[mark_reh]

crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games. Every station broadcasts continuous running advertisements interrupted occasionally by "programming", which is itself mostly advertising. We have a lot of stupid people in the US, but how even they listen to that for more than a few minutes at a time?

AM broadcast radio is going the same way SW radio (also AM broadcast, except at higher frequencies) did back in the 80s and 90s. The big players give up on it, then the religious nuts take over, then it fades into obscurity.

Re: If AM radio is dying, it is because of the

[DNS-and-BIND]

The entire reason the right is on AM radio is that they were banished there by the left wing media. They made sure all the good media that reaches millions were purified of dissenting thoughts. The right was marginalized all the way back to AM radio, a medium that hasn't been relevant since the 70s. And it appears that isn't even good enough, eh? Banish them from AM as well? Jesus.

Re:Tower rentals are expensive

[mark_reh]

I predict that the hipster-doofusses who are reviving vinyl records (you know, neck beards and man-buns) will eventually catch on to AM radio and it, too, will become a thing again - for a little while, until they discover CDs and FM radio...

Re:Make towers that look like trees

[freeze128]

In the midwest where I live, I have noticed an increasing trend to hide cellphone towers inside modern church belltowers. This probably helps to offset the cost of building the church, because the cellphone carriers have to pay for upkeep, and maybe purchase the land.

I have never attended any of these churches, but I comically imagine that "Today's sermon brought to you by Sprint. GOD, can you hear me now?".

AM towers AREN'T grounded....

[Ellis D. Tripp]

The tower itself generally acts as the antenna radiator, and sits on a big ceramic insulator at the base. The tower is at a high RF voltage in reference to earth ground.

Attaching auxiliary equipment to an AM tower would be a nightmare because of this fact. everything on the tower would be floating at hundreds/thousands of RF volts above ground. The power into and data out of the equipment would need special decoupling/filtering to keep the RF on the tower and out of the power/data lines. Sensitive electronics in general aren't going to like becoming part of an antenna like that, and the loading effect of bolting "stuff" onto the tower may shift the FCC-regulated radiation pattern of the station, as well.

We need to keep ALL of that old infrastructure.

[jenningsthecat]

The AM broadcast-band, (and its close relatives, the short wave bands), allow for long-distance radio communications. Even in the daytime the coverage is pretty good; but at night, when the ionosphere allows for 'running skip', its reach is truly impressive. There may be times in the future when that's crucial for reaching people over very large geographical areas. We really need to backstop our wired networks with wireless analog broadcast capability. It can reach anybody who has a $5 pocket radio, it continues to work even when all you have is batteries or generators and a tower, and it doesn't rely on hard links that can easily be broken. And it's already there, fer chrissake - all we have to do is maintain it.

Re:We need to keep ALL of that old infrastructure.

[kenh]

Self- or battery-powered AM/FM radios are typically included in any "hurricane survival" preparation list.

AM towers are RF hot, folks

[swschrad]

unlike TV and FM towers, the AM tower > IS the antenna. the tower is hot. they are isolated by placing them atop large ceramic insulators. if the station is still on the air, this poses gigantic grounding and potential RF coupling into a cell service.

Re:hardly news

[Strider-]

AM tower arrays usually are not shared, as the entire tower is the radiator. Other electronics don't like being excited by 50kW of RF energy.

Re:Does cellular have an expiration date?

[jwhyche]

When and where is the point of critical mass going to occur? Where I'm going with this is: What's the technology that's going to ultimately have to be developed to replace this technology?

It's already here. It's called voice over wifi and is exactly what it sounds like. When your phone is on wifi all calls are routed through the wifi connection. My S7 had it and my S8 has it. I think most iPhones have it now.

On my S7 it wasn't quite right. I could move from a wifi call to cell tower and it would ether drop the call or there would be a loud hiss during the conversion. With the S8 that issue is gone. Now when I move from wifi to cell there might be a little click when I do.

With those xfinity hotspots all over the damn place I can actually move around town and never really leave wifi calling.

Re:Does cellular have an expiration date?

[jwhyche]

While I agree with you that it is a band-aid its not as bad as you make it out to be. Depending on where live. Where I live virtually every business has a public Wifi and wifi hotspots are easy to hide.

Two years ago I worked in the cell phone industry. The technology that you are looking for is VoLTE. Which stands for voice of lte. Basally, they plan to remove the phone network and route all calls over the LTE data stream. I believe they are already doing this in some areas.

VoLTE will mean less antennas but with more capacity. I'm not sure LTE 4 is up to the demand of going main stream but I believe LTE 5 will be able too. I think that LTE 5 has a 1000 times more capacity than lte 4. Don't quote me on that. I left the market before LTE 5 became the "thing to watch." I'm sure someone will correct me soon.