If Skype continually is dropping calls there could be many reasons that are causing this issue.
One workaround for this issue is to change the skype connection to a specific software port on your computer.
*** Please be aware to let the other people trying to connect with you to use the same port number or they won't be able to connect ***
To change the port:
1. Open Skype and sign in
2. Click on "Tools" in the top menu bar
3. from the "Tools" drop down menu click on "options"
4. Then from the options window click on "Advanced" tab in the left hand column
5. Then click on "Connection" under Advanced in the left column:
6. Uncheck the box labeled "Use port 80 and 443 for additional incoming connection" and choose a number greater than 1024 and enter it in the box above.
7. Make sure to give that number to other people trying to connect with you and walk them through changing the port in their settings.
8. Close Skype and restart it and then try to make the call again.
Hopefully that will help connect the calls.
After making the call make sure to go back to those setting and then check the box "Use port 80 and 443 for additional incoming connection" again for general calls in the future.