I
have full confidence in the ability of Chris and Paul to craft an appropriate
petition on this question. With each posting on this topic it is becoming more
apparent that the allocation by bandwidth resolution has ramifications far
beyond those discussed in July. More specifically there appear to be a variety
of opinions as to what the petition is intended to accomplish and the specifics
of what is to be included in the request to FCC. Without that information Chris
and Paul are left to interpret what was intended.
Rather
than risk an unfortunate encounter with the Law of Unintended Consequences we may
prefer to wait until January to clarify what we intended to request and how to
do that as narrowly as possible. The other option is to proceed,
in which case the only Board wide guidance that Chris and Paul have is the
language of the motion rather than our individual opinions of what was
intended.
Jay KØQB
Dave:
6kHz is
not okay for SSTV as it is image. Therefore, bandwidth is limited to a max of 3Khz.
Dennis
-----Original
Message-----
From:
Sumner, Dave, K1ZZ [mailto:dsumner@arrl.org]
Sent:
To:
arrl-odv
Subject:
[ARRL-ODV:7726] Re: ARRL & Bandwidth
Art
Goddard suggested I share with you the following exchange that he and I had a
few months ago.
Dave
K1ZZ
-----Original
Message-----
From:
Art Goddard [mailto:w6xd@attbi.com]
Sent:
To:
David Sumner K1ZZ
Cc:
Jim Haynie W5JBP
Subject:
Is there a Limit?
Hi
Dave-
At
"Hi-Fi"
operation on 14.178, and other frequencies.
According to these
members,
the Hi-Fi proponents have modified their radios for
up to 6KHz of
audio
bandwidth and are unnecessarily disrupting nearby operators.
97.307(a)
says use no more bandwidth than necessary. ITT's Reference Data
for
Radio Engineers states that 3KHz is the necessary audio bandwidth for
communications-quality
radiotelephone and 4-10KHz for sound broadcasting,
"depending on the quality desired". Since broadcasting
is prohibited
(97.113)
what is the justification for broadcast audio in the Amateur Radio
Service?
Is
there any limit? Is SSB with 6KHz bandwidth (J6E) OK?
The ARRL FCC Rule
Book,
12th ed., p 4-27, appears to side with the HI-Fi
folks, bounded only
by
"good amateur practice". If J6E is OK for SSB radiotelephone, then 6KHz
is OK
for SSTV and any other non-phone emission (97.307(f)(2)). And if 6KHz
is OK
for SSB, then 12 KHz is OK for AM.
May
QST, p13, carries an ad for Ten-Tec's Jupiter radio heralding "Great
Audio!"
with built-in DSP selection of transmitted audio up to 3.9KHz
to
"deliver the finest sounding audio in amateur radio". By
carrying this ad,
we
have aligned ourselves with the Hi-Fi proponents, at
least in some
people's
eyes.
"It
Seems to Us" there's an opportunity for ARRL to
provide some guidance
here...
73,
Art
-----Original
Message-----
From:
Sumner, Dave, K1ZZ
Sent:
To:
'Art Goddard'
Cc:
Jim Haynie W5JBP
Subject:
RE: Is there a Limit?
Hi
Art,
Occupied
bandwidth is defined as 26 dB down from mean power. The bandwidth of a voice
signal is heavily dependent upon the individual voice characteristics. Even if
a transmitter is deliberately designed to pass voice frequencies above 3 kHz,
it will be a rare voice that contains much energy at those frequencies.
Looking
at it another way, is there an affirmative obligation on an amateur to filter
out of his or her transmitted voice signal, frequency components that are
present in his or her voice? I don't believe there is.
Poor
IMD characteristics and excessive power are more likely to cause problems than
broad transmitter filters, it seems to me. But I admit that I seldom listen
with a filter wider than 500 Hz.
73,
Dave
K1ZZ