dmehus wrote:Curious, why would they have had to have moved to Pattison's transmitter sister site to move CISL from 650 to 600 on the AM dial? Wouldn't that necessitate a CRTC application just as much as maintaining their current transmitter site but flipping from 650 to 600?
Pattison's transmitter site was previously used for a 10,000 watt station on 600 KHz, so has the towers spaced out properly to create the daytime and night-time directional patterns that are guaranteed to be approved by Industry Canada as properly protecting other stations on that frequency. Towers, their wiring, and the land they occupy make up the primary cost of a transmitter site, especially in an expensive real estate area like Greater Vancouver.
Moving a transmitter site on the same frequency is mostly about satisfying Industry Canada that you are still adequately protecting stations on the same and adjacent frequencies; the CRTC's main interest is to ensure that existing listeners don't lose your signal when you move to the new transmitter site. Changing frequencies is a whole different matter, requiring a lot longer process that involves more scrutiny by Industry Canada and a sometimes lengthy CRTC application process.
dmehus wrote:Also, why is it a "lost opportunity"? Is there something else on 600 AM now
The CRTC has approved a new station on 600 KHz, to move the programming of KRPI-1550 to a Canadian transmitter. They are not on the air yet, as there is a lot of work to be done to get the Pattison site in shape for sharing with CISL-650.
dmehus wrote:As far as cutting down expenses, I'm surprised the radio station operators don't utilize the roofs of their corporate/station offices from their towers in Vancouver? One would think skyscrapers would make excellent radio transmitter tower locations - they might even be able to negotiate a lower "per square foot rate" on their office space taking in to account them now leasing rooftop space as well.
This morning's Today in Broadcast History hinted at the fact that putting AM transmitters at higher elevations does not guarantee a good signal. CKLG tried that when they first signed on.
With the notable exception of the technology that KFBK-1530 Sacramento uses, AM stations transmit from one or more tall towers with very good ground conductivity. The full tower is used to create the radio wave. Multiple towers create directional patterns by being placed specific distances from each other and each transmitting in a different phase, sending more signal in one direction than another.
In the 1920s, a major topic at Radio Conferences where the U.S. government was trying to solve a lot of radio problems, was getting transmitters outside of "City Limits", because they caused so much interference. AM, long before FM and TV were popularly available.
Today's FM and TV are completely different because of their much higher frequency (than AM). The signal is radiated from a small antenna near the top of a tower, rather than using the entire tower to radiate the signal as is done on AM.
In those early days of radio, (AM) transmitters in Cities usually used a single wire between two towers to transmit the signal, not the towers themselves. Like KFBK, this eliminated the need for a swamp or other area of great ground conductivity.
dmehus wrote:What surprised me was that Bell Media kept both its AM frequencies, airing its sports radio operation on both
I don't live in Vancouver, but I have not heard of any simulcasting between Team 1040 and Team 1410. Even if they did do some, the rationale for two frequencies still makes good sense, since Hockey Season and Football Season do overlap. Each can be on a different frequency.