[Lowfer] Looking for 73 kHz band modes to try...

[jrusgrove at comcast.net]

It's ROS mode that's involved in the spread spectrum controversy. OPERA mode is simply on off 
keying.

Jay W1VD  WD2XNS  WE2XGR/2  WG2XRS/2


----- Original Message ----- 
From: "JD" <listread at lwca.org>
To: "Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands" <lowfer at mailman.qth.net>
Sent: Thursday, December 05, 2013 8:06 PM
Subject: Re: [Lowfer] Looking for 73 kHz band modes to try...


>>> Opera is not legal to tx in the US, FCC thinks it is a spread-spectrum mode.

Actually, Cliff, that's what its own, er, inventor called it, way back when.
Perhaps they took his word for it.  It's not really SS, of course.  It uses
no energy-spreading techniques; it's merely frequency agile.

But it's still not legal below 50 MHz in the US amateur service for a much
more fundamental reason...the same reason WSPR and PSK31 and others *do not*
meet the published Part 97 requirements on HF, either!

In 160m and all relevant segments of the HF bands through 12 meters where
RTTY and data are permitted by Sec. 97.305, Note 3 of 97.307(f) also
applies:  "Only a RTTY or data emission using a specified digital code
listed in §97.309(a) of this part may be transmitted. The symbol rate must
not exceed 300 bauds, or for frequency-shift keying, the frequency shift
between mark and space must not exceed 1 kHz."  (At 10m, it's Note 4
instead, which is exactly the same except for a 1200 baud symbol rate.)

Well, obviously the baud limits and the maximum frequency shift are not the
problem.  But if you follow on to 97.309(a), you find that there are only
three coding methods specified for RTTY and data emissions...5-level Baudot,
AMTOR, and ASCII.  That's all!

Unspecified codes _are_ permitted by Notes 5 and 6, but those notes apply
only within bands above 50 MHz.  Thus, OPERA and the other aforementioned
modes are legal up there, with a few restrictions.  And, Part 5 licensees
are not under the requirements of 97.309(a) at all, so there's presently no
problem using any of these modes in the US at LF and VLF.

(QRSS employs International Morse, the coding method explicitly defined for
CW in 97.3(c)(1) and permitted virtually everywhere in the ham bands by
97.307(a).  Hellschreiber is an image mode, on which few specs are stated in
the Rules other than bandwidth limits, so no problem there either.)

But assuming we do someday get 2200 and/or 630 meters in the amateur
service, one of two things will need to happen before it's legitimate to use
popular digital modes in those bands:  (1) there will need to be yet another
new slow mode that does, in fact, utilize one of the currently specified
codes; or else, (2) developers of this sort of software will need to get
together and agree on a nice, efficient varicode they can all get behind,
publish it, and then petition the FCC to include it in the specified codes
of 97.309(a).  I have no doubt most of us here would gladly support such a
petition.  Then some variant of each of these worthwhile digimodes would be
legitimate for American ham use in all bands.

73
John

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