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[Ham-80211] HSMM: 420-430 MHz

kb9mwr at gmail.com kb9mwr at gmail.com
Fri Mar 4 20:34:26 UTC 2011

Here is some explanation from the QEX article, for those concerned:

In 47 CFR 97.315 the emission type "image" is defined as including
"emissions having B as the first symbol; 7, 8 or 9 as the second
symbol; W as the third symbol".

In 47 CFR 2.201 (c) (2) a first symbol of B defines the type of
modulation of the main carrier as an "emission in which the main
carrier is amplitude-modulated (including cases where sub-carriers are
angle-modulated) with independent sidebands". The OFDM modem fits this
description as it has a central carrier with multiple subcarriers in
the upper and lower sidebands that are angle (phase) modulated. In 47
CFR 2.201 (d) (5) a second symbol of 7 indicates that the nature of
the signals modulating the main carrier are "two or more channels
containing quantitized or digital information". 47 CFR 2.201 (d)(2)
and (3) indicate that time-division multiplex is excluded for a single
channel so the time division multiplex inherent in HSMM communications
creates two or more channels.  In 47 CFR 2.201 (e) (8) a third symbol
of W indicates that the type of information to be transmitted is "a
combination of the above" and that includes (4) "facsimile", (5) "data
transmission, telemetry and telecommand", (6) "telephony" and (7)
"television". HSMM fits this definition as it includes data, speech
and image components.

I am more concerned by underutilized spectrum, and red flags that
people throw that deter experimentation in the hobby.

That said I have a few extra picture frames and would be fine framing
my first "pink slip" over silly rules in the name of experimentation.

I firmly believe that the rules will change as we do.

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