WH2XBH licensed to MIT Lincoln Laboratory has a transmitter location of 42.624N, 71.486W which is at MIT Haystack Observatory near Westford, MA. The licensed frequencies are useful for probing the ionosphere across a range of HF frequencies. HF experimental licenses are in general not contiguous across the HF bands because of protected radio services such as government, aircraft, public utilities, and the like.
WH2XBH is licensed at 1 Watt ERP with condition “the occupied bandwidth of the emission shall not extend beyond the band limits” for (approximately, see license for exact bounds):
|Start freq [MHz]||Stop Freq [MHz]|
ITU/FCC Emissions designator
Generally the emissions are of type 500KW0W except where narrower. The fifth letter refers to the modulation being sent.
- fifth letter
- modulation. Here, it’s
W, which means any type of modulated or unmodulated transmission.
- sixth letter
- information content. Here, it’s
0, which means no inherently useful information is sent. Modulation is sent, but it’s modulation useful for radiolocation, not for sending messages as a sole end goal.
- seventh letter
- information type. Here, it’s
W, which means any type of information may be transmitted. This might seem to conflict with the 6th letter, but what it actually means is you can send any type of content, as long as information transmission is not the purpose of the transmission. I can send jumbled up pictures or random numbers, but not broadcast a TV or music program for listeners to enjoy.