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February 2, 2021 1:34 pm  #1


Is the clock ticking for ageing AM broadcast facilities?

From what I have read, it appears that a well built and maintained directional AM transmitter array consisting of several towers can be expected to last 40 to 60 years before the towers and ground radials will need to be rebuilt / replaced. The former CKSL was built in 1964 and its towers held up well enough to operate through 2016. That's 52 years of operation. The station owners asked to shut it down due to the expense of replacing its aging towers among other issues.

In the last 15 - 20 years CKLW AM 800 Windsor and CHYM 570 Kitchener have replaced their towers giving them another potential 30 years of service. So if say 50 years is kind of a benchmark for the life of a transmitter facility, how many AM stations are approaching the service life limit of their sites. I'm sure there are variances in my 50 year life expediency depending on the soil and type of materials used so some sites may do better than 50 years and some less.

For profitable stations that have budgeted for the eventual replacement of their towers / equipment this would probably not be a problem; they will replace as necessary. What about the marginal ones where only a small profit is made. As the site ages out what do they do? Especially if the land their site occupies is adjacent to cities with ever increasing land values. I have a feeling in the next decade we may see more stations go silent as the clock ticks.

What do your think?
 

 

February 2, 2021 3:28 pm  #2


Re: Is the clock ticking for ageing AM broadcast facilities?

Has transmitter technology improved at all so that cheaper facilities (or at least smaller facilities that require less land) are possible? 

 

February 3, 2021 2:48 am  #3


Re: Is the clock ticking for ageing AM broadcast facilities?

The technology is largely the same for AM sites as they have always been.

 

February 3, 2021 12:42 pm  #4


Re: Is the clock ticking for ageing AM broadcast facilities?

Prod Guy wrote:

The technology is largely the same for AM sites as they have always been.

Unfortunately we're still at the mercy of physics. Our AM frequencies are in the Medium Wave band whereas our FM frequencies are in the VHF band.

For some perspective on transmitter site requirements, the wavelength of CFRB on 1010 KHz is roughly 300 meters, whereas the wavelength of CKFM on 99.9 MHz is roughly 3 meters. Orders of magnitude of difference and that means transmitting facilities need to adhere to these realities..

 

February 3, 2021 1:13 pm  #5


Re: Is the clock ticking for ageing AM broadcast facilities?

What would be the wavelength for 550 WGR and 1520 WWKB? More or less than RB? Or is it pretty much the same across the entire band?

 

February 3, 2021 1:39 pm  #6


Re: Is the clock ticking for ageing AM broadcast facilities?

mace wrote:

What would be the wavelength for 550 WGR and 1520 WWKB? More or less than RB? Or is it pretty much the same across the entire band?

550 kHz = 545.0771963636363 meters
1520 kHz = 197.23188026315788 meters

 

February 4, 2021 1:31 pm  #7


Re: Is the clock ticking for ageing AM broadcast facilities?

Like Tim Brown 2016 says, it's the physics of the frequency or wavelength of the signal on the AM band. Many / most AM stations are directional and send their signal toward the area they wish to serve. This reduces interference and allows more use of the frequency in other areas.

Because of the wavelength stations require additional towers spaced appropriately that interact with each other to create the directional pattern. This pattern often changes at sunset / sunrise. The towers are usually spaced 100's of feet apart.  Some stations can achieve this with two or three towers, others need five or more. CJBK 1290 in London has eight or nine towers, hence the requirement for a relatively large parcel of land.

I think there are many stations that renewed their sites in the 1970's and 80's when AM was making them decent money. Forty to fifty years has passed (it sure flew by didn't it) and these transmitter sites are approaching the end of their useful life. 

When Bell shut down CKSL 1410 London, they claimed it would cost in excess of three million dollars to bring the site up to current safety requirements and the station's ratings / revenue were too low to justify the costs of doing so.
 

     Thread Starter
 

February 7, 2021 11:44 am  #8


Re: Is the clock ticking for ageing AM broadcast facilities?

CFRB and CHUM are sited on some high-priced property in Mississauga. Indeed part of the RB site is now retail, including Canadian Tire.
The new Oakville hospital is beside the CJYE/CJMR site.
There's housing sprouting up near the CFTR array in Grimsby... ironically since CFTR and CHIN moved out of Mississauga to make room for residential/industrial development.
As for CKOC/CHAM - CHAM is located on the edge of Binbrook, and would be choice residential. CKOC is fairly isolated out by Empire Corners, but there have been some high-end mcmansions going up near there, so maybe...
 

 

February 7, 2021 11:47 am  #9


Re: Is the clock ticking for ageing AM broadcast facilities?

Ida Spencer? I thought you were still missing!

 

February 7, 2021 12:52 pm  #10


Re: Is the clock ticking for ageing AM broadcast facilities?

Not now; just in isolation