It would be nice to have some more detailed specs on the Solo.

What is its max altitude above sea level?
There aren't enough specs available to use ecalc to figure out max altitude.  At least I don't think there are... I've never used ecalc myself.

Anyway, here are the specs I've found so far:

• Flight time: 25 minutes. (20 with camera/gimbal)
• Top speed: 55 mph (70s in manual)
• Max altitude: 400 ft, per FAA rules. (¡duh)
• Max altitude above sea level: [???]
• Weight: 1500 g; 1750 g with Solo Gimbal and GoPro (some reports say 1800g)

• Motors: 880 kV
• Props: 10 x 4.5 (self-tightening) 
• Battery: 4S 14.8 Volt LiPo (5200 mAh)
  • "Smart battery" - reports status to controller, tracks its own cycles etc.

• Wifi: 2.4ghz (built into controller)
• FPV: 720P (over wifi).
• FPV Range: half mile / 800 meters

• Controller:
  • Mode 2 Stick defaults
  • 2.4ghz wifi base station built in
  • Rechargeable battery. 4 hours - 2600 mAh / 7.2 Vdc. (extendable battery available)
  • Color screen with live flight data
  • Camera/gimbal control buttons (tilt, presets angles, tilt speed, etc).
  • A and B buttons for Cable Cam
  • Fly Button
  • "Panic" pause button.

• Flight Controller: Pixhawk 2
• Flight Control Software:   APM
• Linux on drone and in controller
• Wireless software updates

• Compatible Ground Station Apps:
  • Solo App:
    • iOS + Android
    • Video Feed (FPV)
    • Control GoPro
    • Fancy flight modes: Cable Cam, Selfie, Follow-me (and others)
    • Very limited mission planning (all done via flight modes described above)
    • Trouble tickets.
    • Access logs.
    • Easy to use (params become sliders)
  • Tower App:
    • Android only
    • Comprehensive Mission Planning
    • Comprehensive access to Parameters
  • Mission Planner:
    • PC Only
    • Comprehensive Mission Planning
    • Comprehensive access to Parameters
    • Comprehensive log analysis
    • Most stable, and fully featured ground station
  • APM 2:
    • Mac and PC
    • Similar to Mission Planner, but not as good/stable.

• Expandability:
  • Accessory "bay" and Standard Port Connector for add-ons (optical flow, ballistic shoot, etc)
  • Open platform - accessories and 3rd party gimbal / camera combinations allowed.

• Fancy lights: Customizable color LEDs for orientation. Also helps distinguish between 2 Solos in the air at the same time.

• GoPro Centric:
  • 3DR Solo Gimbal designed for: HERO 3, 3+ and all HERO 4 models
  • Control GoPro from the ground. (change settings, take photos/video)