Corporate aircraft cleared for takeoff on Runway 23L at GSO was questioned after takeoff by the Local Controller; alleging their takeoff clearance had been canceled twice; reporter's claiming; no cancellation clearance was received.

Narrative

During taxi for takeoff to Runway 23L at GSO we were using radio two; at the end of the runway we switched to the number one radio and told the tower we were ready for takeoff. The tower cleared us for takeoff and the transmission was clear and understood by both crewmembers. At that time there was an aircraft that was in the pattern for landing who informed the Tower they were going to make a short approach due to their cowling being loose. The PIC elected to wait to see if the Tower wanted to cancel our takeoff clearance. After several seconds there was no response from the Tower and since we had already passed the hold short line we decided to continue the takeoff. During the takeoff roll we heard the Tower say they are on the roll you are cleared to land. Right after takeoff; before the SIC could even get the gear retracted; the Tower is calling so I answered and the Controller wanted to know if I heard them cancel our takeoff clearance. Controller said they tried three times. I told Controller we heard nothing; and we even waited a short period to see if they were going to call; we did not even hear a broken transmission. The Controller did not even wait till we completed our takeoff to question us. This was not safe because it interrupted our flow after takeoff and is a critical time of flight. After switching to the departure frequency I explained we heard nothing from the tower when this happened. They explained that there is a dead spot at that part of the airport and there were more times that this has happened and they know this. We looked several times before we took the runway and could never see the aircraft that was on the approach.