I haven't commented on this previously, but it's kinda getting out of hand, with certain people making surly and unfriendly commentary, so I'm gonna throw in my 2 cents.
First of all, the frequency 170.7 is the repeater input for 171.27. Transmissions heard on the input frequency of a repeater will only be heard near to a vehicle or portable radio transmitting, or a tower with the frequencies 'flipped' (see below). Most often, the reason for 'flipping' a tower's frequencies is to transmit from a base station into a far-away repeater site, and it's not meant as a repeater site used to enhance coverage of the system. Does that make sense?
Second, the frequencies for Airdrie Emergency Services are 169.74 for Fire and 171.27 for EMS, as shown in the DB here, and the TAFL. Airdrie has towers for these frequencies at 15 East Lake Hill (presumably the Airdrie public works yard) and at Rotary Park in Calgary. Tower sites in the TAFL are denoted with an "FX" in the class of station field, meaning "fixed". Furthermore, if you look at the frequencies for the towers as shown in the TAFL, the frequencies are 'flipped', meaning that the tower at Rotary Park is actually transmitting on 170.7, the repeater input frequency - which is why robertmac can hear the signal so well in the center of Calgary. The only place where the Airdrie Fire & EMS repeaters are transmitted "normally", looking at the TAFL, is from the East Lake Hill site. So, by nature of geography and how radios respond to tall buildings, trees, hills, and etc., there are a lot of places in the south and west parts of Calgary that are not going to hear Airdrie comms very well. It's probably safe to say that the folks that built Airdrie's radio system are only interested in signal coverage in their city plus whatever it takes to get to the various hospitals their ambulances transport to.
169.41 is the Airdrie public works department, as I discovered myself through plain old "sleuthing" (listening to the freq a lot and piecing together the conversation) several years ago. Are you guys saying it's TRBO now? I haven't listened to it in ages. If it is TRBO, someone should submit that to the DB and an admin will work it.
And to explain why you can hear Cochrane Fire/EMS so clearly: As shown in the TAFL, Cochrane has a tower and a channel located on the 90m ski jump at Canada Olympic Park. It's designed to cover the city, while the Airdrie system, with no "normal" tower in the city, is not.