Part 91 pilot reported that there was a ground conflict with another aircraft that crossed the runway while climbing after takeoff.

Narrative

It was a clear cool day with a few cirrus clouds overhead. I started the engine; listened to the ATIS and set my altimeter. I switched to CTAF. I taxied out to the run up area at Runway 31; via Taxiway B. I have dual electronic ignition and accomplished the 'mag' check at low RPM while taxiing as I usually do. I stopped at the run up area. The wind sock at Runway 31 at MTJ showed a very light breeze nearly parallel to the runway. I increased the RPM to 1700 and listened to the engine while the oil temp increased to 110 F. During this time I heard another aircraft announce entering into the pattern. There was also a call from a small aircraft but I was not able to understanding anything other than their make and model. I made visual contact with an aircraft on downwind; a little before abeam midfield for Runway 31; left traffic. I had the engine heater plugged in from the night before and the oil cooler is configured for winter flying so getting to take off oil temp did not take very long. I scanned the pattern visually while turning prior to taxiing onto Runway 31. Again I saw the aircraft I previously saw on downwind; he was turning left base roughly a mile and a half out. I looked for traffic in front of the plane I had a visual with. I saw no other traffic in front of him. I also looked for traffic for Runways 35 and 17 and determined it was clear. I announced that I was taking Runway 31 for a right cross wind departure. I kept talking that I had the aircraft on left downwind in sight and that I was taking off without delay; and that I was looking for the other traffic. Prior to lift off speed; but well into the run; I saw a business class jet taxiing towards the terminal on Taxiway C or D. I would have seen it earlier but it's vertical stab and rudder were painted black. I anticipated he would stop prior to crossing Runway 31. I continued the take off run and was becoming airborne right about the time I realized he wasn't going to stop and right about then he called out that he would be crossing Runway 31. While I was passing over head I radioed him not calmly; to the effect; didn't you hear my take off call out. He replied no he didn't. His tone of voice indicated his unease. I replied calmly I was sorry and that my radio antenna is under the belly of my plane; unstated but; implying that may have been the reason. I continued my departure. If anything like this ever happens again; I will abort the take off even if I had made the radio call out and there is someone; by then; on final behind me. It's a wide runway and I can easily hug it's left side. Previously I had waited at the run up area more than a few times for the airliners to taxi in across Runway 31. I radioed that I am holding in place at the run up area and have them insight. They have always acknowledged my call and say 'thank you.' Additional factor ; MTJ isn't completely flat. With my antenna under the belly; it seems it can be a factor for reception for another plane taxiing in along Taxiway A. I think that small aircraft that I didn't fully understand was the business jet. The other thing I will do differently now on is that whenever I hear something that isn't clear; I'll transmit a request for them to repeat it; even if it is a smaller aircraft. I did not give that transmission the importance it deserved because I thought it was an airborne plane piston further away. Also; I should have radioed the business jet to stop prior to crossing Runway 31L missed that during the high stress situation. I was extremely focused on flying the airplane.