Airport frequencies

[FDXDave]

So I've seen two frequencies for like Ground control and or Towers. One usually is a low number. the other usually starts in the 200's or 300's.
Example.
PHOENIX GROUND:
119.75, 132.55, 269.2
PHOENIX TOWER:
120.9 (RY 07R/25L & 07L/25R)
254.3 (RWY 07R/25L & 07L/25R)

So I usually choose the lowest of the numbers for what ever reason.
Maybe because my thinking is GA AC uses the lower freq and maybe Military uses the higher freq.
So being I fly GA and Airliners, I try to stick with the lower freq's. But This is just a guess. I have not
read this anywhere. Can someone tell me the difference please?
So far I have never had ATC tell me I'm on the wrong Freq.
Plus on PE Live Map, regardless of which freq I choose the suffix
remains the same. It will still say tower either way.

Part two of the topic.
I never ran into this before the other day. But you take
City of Colorado Springs for example. The Freq's do not match up at all.
I planned my flight from Denver to COS and I always go to the main airport page in
Skyvector to look at Freq's. So I wrote down COS Approach, Tower and Ground.
They are as published.
SPRINGS TOWER: 133.15 335.55
SPRINGS GROUND: 121.7 348.6
SPRINGS APPROACH: 120.6 124.0 257.875
SPRINGS DEPARTURE: 124.0 257.875

So mind you I had planned for a GPS runway 17R Approach.
So to my surprise ATC tells me to go to COS APPR 124.00
I'm like ok, but thinking that is not what I had wrote down.
Then I'm told to switch to tower on Freq. 119.9. I'm like ok again.
Again, not a Freq which was published.
So looking more closely at the approach chart for GPS Y 17R plate. I saw where
they were getting their Freq's from. All the Approach charts to include the airport diagram chart
has the lower frequencies used. So ok, now I know where they get their information from.
But I still do not understand why Colorado Springs main page has all the frequencies wrong....
They are using a departure Freq for an Arrival? And the Tower is not even listed on the main page.
On any other flight I have done, I have always found the right frequencies on the main page.
Most of the time it will break it down to even which freq for which runway, or side of the airport you use.
And the other airports approach plates have the same freq's published. So why is COS so different?

Thank you : )

Dave.

[Marcus Becker]

Part one:
You missed something on the airport diagram.
GND CON
119.75 North
132.55 South

At least most of the time, diagrams will have that descriptor there.

[Marcus Becker]

Part two:
Probably has been explained more times than I have fingers but the idea is that (just like sometimes in the real world) sectors are combined. The frequencies you have listed are both valid COS radar frequencies so you shouldn't be concerned about why you got a departure frequency on arrival.

I don't know any pilot that this scenario negatively affects. If a controller gives you a frequency to change to, it takes a matter of seconds to change to that frequency and announce your beautiful presence. When they give you another frequency to change, dial it up and do it again. Knowing what frequency you think you should be on ahead of time shouldn't have any benefit. Am I wrong?

[rtataryn]

part 1. Yes, frequencies in the 200 and 300 MHz range are for military aircraft. Disregard. Your radios won't tune them anyway.

part 2. What Marcus said.

[kullery]

In regard to the tower frequency “discrepancy”, KCOS has changed tower frequency usage during the past few years (I’m not sure exactly when). When this occurs, it takes a while for all reference sources to get updated. Even within the official FAA data sources, procedures and the A/FD update on different cycles so it’s possible for them to be out of sync.

In this old airport diagram from 2014, you can see that KCOS previously used a split tower frequency using both 119.9 and 133.15.

D9819C34-08B1-44F0-8101-2CA08498AE28.jpeg (96.59 KiB) Viewed 3400 times

[FDXDave]

Part two:
Probably has been explained more times than I have fingers but the idea is that (just like sometimes in the real world) sectors are combined. The frequencies you have listed are both valid COS radar frequencies so you shouldn't be concerned about why you got a departure frequency on arrival.

I don't know any pilot that this scenario negatively affects. If a controller gives you a frequency to change to, it takes a matter of seconds to change to that frequency and announce your beautiful presence. When they give you another frequency to change, dial it up and do it again. Knowing what frequency you think you should be on ahead of time shouldn't have any benefit. Am I wrong?

Thank you Marcus for the explanations. I certainly hope I did not come across as complaining that I had to use a Freq I had not planned on. I certainly did not state over the MIC anything other than repeat the freq. The first time, I confirmed the freq which was given to me. So not ever has this, nor will it in the future negatively affect me. This is a hobby. I am not a real pilot. I am disabled and can never get a real pilot license. SO I use these forums, and other means of learning this skill. Such as Kieth's instructional videos and VATSTAR's training for VATSIM. I also have watched hundreds of youtube videos lol... In an earlier post I had posted a topic about planning my flights. During that discussion it was learned I should not bother with planning Centers or even approach Frequencies because they can change all the time. That I should only plan on the tower. So really the only time that i was truly confused was when I was given the tower freq...cause I did have the other one wrote down. Speaking of learning something new. This weekend I celebrated my 46th B-day. As a gift I got myself a new GA style Yoke to use. Before this I have just used the good ol' twist grip fighter style joystick. This yoke has the thumb pads for rudder and steering. So I'm taxing and turning the wheel left like in a car to turn left......Yep doesn't work like that lol..
But I'll get there. : )


kullery Thank you for your illustration. Never did it occur to me that these charts could fall behind. But it makes sense. How could any agency update all the changes 100 % of the time.
And I did miss the part where the Ground was using two different sides of the airport.

rtataryn Thank you for clarifying my guess. It's nice to guess and be correct for once. lol.

Thank you all for taking the time to help me understand this subject matter even more. I really am enjoying learning this trade. I think I have come along way, considering, I just picked up this hobby not even 6 months ago. Now the controllers don't correct me nearly as much lol.

Dave.