Shorter than 1 mm band

Amateur stations transmitting on the 275-323 GHz segment, and the 327-371 GHz segment, the 388-424 GHz segment, the 426-442 GHz segment, the 453-510 GHz segment, the 623-711 GHz, the 795-909 GHz segment, and the 926-945 GHz segment must must not cause harmful interference to radio astronomy stations.

Amateur stations transmitting on the 275-286 GHz segment, and the 296-306 GHz segment, the 313-356 GHz segment, the 361-365 GHz segment, the 369-392 GHz segment, the 397-399 GHz, the 409-411 GHz segment, the 416-434 GHz segment, the 439-467 GHz segment, the 477-502 GHz segment, the 523-527 GHz segment, the 538-581 GHz segment, the 611-630 GHz segment, the 634-654 GHz segment, the 657-692 GHz segment, the 713-718 GHz segment, the 729-733 GHz segment, the 750-754 GHz segment, the 771-776 GHz segment, the 823-846 GHz segment, the 850-854 GHz segment, the 857-862 GHz segment, the 866-882 GHz segment, the 905-928 GHz segment, the 951-956 GHz segment, the 968-973 GHz segment, and the 985-990 GHz segment must must not cause harmful interference to stations in the Earth exploration-satellite service (passive) or the space research service (passive).

On the 1 mm and shorter band, a RTTY, data or multiplexed emission using a specified digital code listed in §97.309(a) of this part or an unspecified digital code under the limitations listed in §97.309(b) of this part may be transmitted.

The 5-unit, start-stop, International Telegraph Alphabet No. 2, code defined in ITU-T Recommendation F.1, Division C (commonly known as "Baudot"); The 7-unit code specified in ITU-R Recommendations M.476-5 and M.625-3 (commonly known as "AMTOR"); The 7-unit, International Alphabet No. 5, code defined in IT--T Recommendation T.50 (commonly known as "ASCII"); An amateur station transmitting a RTTY or data emission using a digital code specified in this paragraph may use any technique whose technical characteristics have been documented publicly, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications.

On the 1 mm and shorter band, a station may transmit a RTTY or data emission using an unspecified digital code, except to a station in a country with which the United States does not have an agreement permitting the code to be used. RTTY and data emissions using unspecified digital codes must not be transmitted for the purpose of obscuring the meaning of any communication. When deemed necessary by a District Director to assure compliance with the FCC Rules, a station must: Cease the transmission using the unspecified digital code; Restrict transmissions of any digital code to the extent instructed; Maintain a record, convertible to the original information, of all digital communications transmitted.

Amateur stations on the 1 mm and shorter band may transmit a RTTY or data emission having designators with A, B, C, D, E, F, G, H, J or R as the first symbol; 1, 2, 7, 9 or X as the second symbol; and D or W as the third symbol is also authorized.

Spread spectrum emissions are authorized on the 1 mm and shorter band with a maximum of 10 W PEP.

F8E emissions (Multi-Channel FM Voice) may be transmitted on the 1 mm and shorter band.

MCW emissions may be transmitted on the 1 mm and shorter band.

Test emissions may be transmitted on the 1 mm and shorter band.

Pulse emissions may be transmitted on the 1 mm and shorter band.