REGULATIONS

The Charon project is intended for educational purposes only.  It is the
end-users responsibility to ensure compliance with local regulations.  If you
are operating within the US, the the following from FCC part 15 may or may not
apply.  Please do take the responsibility to make sure that you are employing
good engineering practices.
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Section 15.23 Home-Built Transmitters that are Not for Sale
  Hobbyists, inventors and other parties that design and build Part 15
  transmitters with no intention of ever marketing them may construct and
  operate up to five such transmitters for their own personal use without
  having to obtain FCC equipment authorization. If possible, these transmitters
  should be tested for compliance with the Commission's rules. If such testing
  is not practicable, their designers and builders are required to employ good
  engineering practices in order to ensure compliance with the Part 15 standards.

Section 15.5, 47 U.S.C. 503 Home-built transmitters, like all
  Part 15 transmitters, are not allowed to cause interference to licensed radio
  communications and must accept any interference that they receive. If
  a home-built Part 15 transmitter does cause interference to licensed radio
  communications, the Commission will require its operator to cease operation
  until the interference problem is corrected. Furthermore, if the Commission
  determines that the operator of such a transmitter has not attempted to
  ensure compliance with the Part 15 technical standards by employing good
  engineering practices then that operator may be fined up to $10,000 for each
  violation and $75,000 for a repeat or continuing violation.

Section 15.7, 47 CFR Part 5 Operating a prototype of
  a product that is ultimately intended for market is not considered "personal
  use." Thus, a party that designs and builds a transmitter with plans to mass
  produce and market a future version of it must obtain an experimental license
  from the FCC in order to operate the transmitter for any purpose other than
  testing for compliance with the Part 15 technical standards. Information on
  experimental licenses may be obtained from the contact point listed in the
  Additional Information section of this bulletin. FCC authorization is not
  required in order to test a transmitter for compliance with the Part 15
  technical standards.