47 CFR §5.71

1. (a)Conventional experimental radio licenses.
   1. (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. (2)A license may be renewed for an additional term not exceeding 5 years, upon an adequate showing of need to complete the experiment.
2. (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.
3. (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.
4. (d)Spectrum Horizons experimental radio license. Licenses are issued for a term of 10 years and may not be renewed.