47 CFR § 5.71 - License period.
(a) Conventional experimental radio licenses.
(1) The regular license term is 2 years. An applicant may request a license term up to 5 years, but must provide justification for a license of that duration.
(2) A license may be renewed for an additional term not exceeding 5 years, upon an adequate showing of need to complete the experiment.
(b) Program, medical testing, and compliance testing experimental radio licenses. Licenses are issued for a term of 5 years and may be renewed for up to 5 years upon an adequate showing of need.
(c) Broadcast experimental radio license. Licenses are issued for a one-year period and may be renewed for an additional term not exceeding 5 years, upon an adequate showing of need.
(d) Spectrum Horizons experimental radio license. Licenses are issued for a term of 10 years and may not be renewed.