[TenTec] Enhanced SSB and listening fatigue

[Adam Farson]

George, Paul,

ITU-R Recommendation M.1173 (technical characteristics of HF-SSB
transmitters for the maritime mobile service) is revealing on this point:

3 The transmitter audio-frequency band shall be 350 Hz to 2 700 Hz with a
permitted amplitude variation of 6 dB.

One can visualise a "Sparks" spending an 8-hour shift in a ship's wireless
office, monitoring SSB traffic on his headphones. It is probably true to say
that listening fatigue in this situation has never become an issue of
sufficient magnitude to prompt any amendment to M.1173.

Best 73,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/



-----Original Message-----
From: tentec-bounces at contesting.com
[mailto:tentec-bounces at contesting.com]On Behalf Of Paul Christensen,
Esq.
Sent: Saturday, April 19, 2003 12:10
To: tentec at contesting.com
Subject: Re: [TenTec] Enhanced SSB


> What are the advantages of transmitting voice frequency components in the
> range of 50 to 300 Hz?

50-100 Hz...zero.
100-300 Hz.  Better balance with the area above 1K and perhaps less
listening fatigue over extended periods of time.

George, I think we all know that 300 Hz to 2 kHz in AM or SSB is all that's
absolutely required to satisfy the following....

 "No amateur station transmission shall occupy more bandwidth than necessary
for the information rate and emission type being transmitted, in accordance
with good amateur practice."

-Paul, W9AC