Bad Comms Today with Center

bigmo

Filing Flight Plan
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bigmo
I *almost* called Center today when I got home - but figured I'd check in with the braintrust here at POA.

Flew IFR into an uncontrolled airport (uneventful). Dropped a family member off. Pretty rural area, so I called bluetooth on the ramp and got my clearance for my trip back home. Easy peasy.

Followed my clearance, climbed out and tried Center (owning facility) at 1K, 2K, 3K, 4K. After 4K, a Southwest pilot called my tail and said he reads me loud & clear. When I got to 5K, my assigned altitude, I could hear Center calling for me, I could hear several airliners in the FLs, and they all could hear me - but Center could not hear me. Center started asking a Delta pilot to relay to me (which I could hear). I identified. Tried com2. Nada. I flipped my CRAFT card over and *duh* - I had the Center frequency from the inbound trip scribbled in. Popped that in and boom - instant comms like I was next door.

I can't quite sort out the mechanics of what happened. How guys 4 miles above me could hear me perfectly and Center could not. I verified 3x I was on the right freq.

I did do comms checks with the next handoff Center, approach, and tower - all good.

Odd enough to call Center and report the dead spot, or just a gremlin that pops up enough?
 
I identified. Tried com2. Nada. I flipped my CRAFT card over and *duh* - I had the Center frequency from the inbound trip scribbled in. Popped that in and boom - instant comms like I was next door.
Not super clear what happened here. You tried them on the outbound CRAFT and they couldn’t hear you so you tried the inbound CRAFT? If so, makes me wonder if they accidentally gave you the wrong frequency in the outbound clearance.

Odd enough to call Center and report the dead spot, or just a gremlin that pops up enough?
I probably wouldn’t bother after landing but I probably would have told them about what happened while en route once COMMs were clear and they weren’t busy.
 
Correct. They gave me the right frequency. The FBO had a "Picking up your clearance" poster - and the freq they gave on the phone matched. It was not, however, the same freq I cam inbound with. As oon as I flipped to that freq, I got them right away with 0 issues.
 
A single sector can be using multiple frequencies from multiple locations. If you were on the wrong frequency for the nearest transmitter, it's possible Center couldn't hear you until you got higher or changed to a closer transmitter. It's also possible the primary transmitter went down and a backup at a second location kicked in.

Our airport has a remote com transmitter for our center on the airport, but the backup transmitter on the same frequency is actually located about 40 miles away. Center won't even know if the system automatically switched. That means they can talk to aircraft on the ground normally, but if the primary shuts down they can't.
 
How guys 4 miles above me could hear me perfectly and Center could not. I verified 3x I was on the right freq.
VHF is line of sight.

You said you were on the right frequency, but then you said it was an error and it started working when you switched to the correct one? Confusing story.
 
VHF is line of sight.

You said you were on the right frequency, but then you said it was an error and it started working when you switched to the correct one? Confusing story.
No, sorry for the confusion.

The freq given to me in my clearance was correct - but didn't work. I was only able to reach them when I reverted to a freq I used on the inbound flight.
 
I had something similar happen once…
I was flying a glider out of a Tower controlled airport.
The procedure was, the glider would call Ground and ask to position on the taxi way. We would position and then the towplane will call ground and pull up in front of us and ground crew would hook us up. The tow plane made the radio to call to the tower for take off from the taxiway, the glider switched to tower and communicated with towplane and just monitored the tower transmissions.
We launched with no issues.
However as I was returning to the airport I tried calling the tower and got no response. After serveral calls I finally called them on my Cell phone and got a clearance to land.
Once on the ground we did some testing with the tower. I could hear them fine on both ground and Tower frequency, But they could only hear me on the Ground Frequency. They switched to their backup transceiver and they could hear me just fine. I wanted to do another flight, so we agreed when I needed to return for landing I would just call them on Ground before going to tower and they would switch to their back up transceiver. This worked just fine.

We or at least I never figured out why they couldn’t hear me. During the ground testing I was probably only 300 yards from the tower but they still could not recieve my transmissions on the tower frequency On their primary transceiver.

Brian
 
I probably would have questioned the guy giving me the outbound clearance when the frequency did not match the one that I was on inbound.
 
Maybe most aircraft more frequently depart in the other direction from that airport, hence getting the different frequency than you came in on...? If you were right between two transmitter sites, but approaching the next transmitter, maybe that one was working better than the one you were getting farther from (even though the first one was the "correct" one, if that makes sense). Also, depending upon your antenna location vs the rest of your aircraft, its possible your antenna has some directivity, making you signal stronger in one direction than the other.
 
Wouldn't 121.5 be another possible solution?
 
No, sorry for the confusion.

The freq given to me in my clearance was correct - but didn't work. I was only able to reach them when I reverted to a freq I used on the inbound flight.
Maybe the controller gave you the wrong one. It happens. For a Center it shouldn't have been different outbound vs inbound. Which one is listed in the Chart Supplement/AFD?
 
How guys 4 miles above me could hear me perfectly and Center could not.
Pretty simple when you think about it - the airplanes 4 miles above you are only 4 miles away. The center's antenna is possibly far further than that.

Kind of like the ISS seems really far up there in space, but it's actually closer than Boston is to Philadelphia. Much closer than San Francisco to Los Angeles. From me here in OKC to Dallas is almost as far.
 
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Pretty long flight today. Three different centers, and like 6 different approaches and 2 towers. All crystal clear.

Gonna chalk this up as it's ATC, not me lol.
 
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