FCC say "a RTTY or data emission using a digital code specified in this
paragraph may use any technique whose technical characteristics have
been documented publicly"
I can't see that you've got any bandwidth restriction on HF subject to each
individual carrier having a maximum symbol rate of 300 baud. That in itself is
a pointless restriction but it doesn't stop you having wide B/W data
transmission using multiple carriers.
In the UK there are no restrictions on modulation techniques or the bandwidth
subject to the transmission fitting within an Amateur band.
73 Trevor M5AKA
--- On Wed, 25/03/09, Dave AA6YQ <aa...@ambersoft.com> wrote:
From: Dave AA6YQ <aa...@ambersoft.com>
Subject: RE: [digitalradio] Phone/Image Band FCC bandwidth limit on HF Re: USA
ham rules
To: digitalradio@yahoogroups.com
Cc: "Dave Bernstein AA6YQ" <aa...@ambersoft.com>
Date: Wednesday, 25 March, 2009, 2:09 AM
The
table in §97.305 (Authorized emission types) indicates that §97.307(f)(3)
applies to all use of RTTY or data emission types in the amateur bands below 28
mhz.
§97.307(f)(3) says "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."
The table in §97.305 indicates that
§97.307(f)(4) applies to all use of RTTY or data emission types on the 10
meter band; it expands the upper limit on symbol rate to 1200 baud, but retains
the maximum FSK frequency shift of 1 kHz.
See
<http://www.arrl.org/FandES/field/regulations/news/part97/d-305.html#307>
73,
Dave, AA6YQ
-----Original Message-----
From: digitalradio@yahoogroups.com
[mailto:digitalra...@yahoogroups.com]on Behalf Of
expeditionradio
Sent: Tuesday, March 24, 2009 6:44
PM
To: digitalradio@yahoogroups.com
Subject: [digitalradio]
Phone/Image Band FCC bandwidth limit on HF Re: USA ham
rules
> Frank k2ncc wrote:
> I think the confusion I have with "quality
phone
> transmission" comment is the part that says
> "...of the
same modulation type."
Hi Frank,
The FCC rule about HF signal
bandwidth limit
related to a "phone emission of the same
modulation
type", applies mainly to Image signals
within the HF "Phone/Image
sub-bands".
That limit DOES NOT APPLY to Data/RTTY signals
in the
Data/RTTY sub-bands.
Beware, there are a few narrow-minded hams
continuing to spread disinformation about digital
bandwidth limits. What
motivates them to do so?
Are they trying to scare us into self-inhibiting
our freedoms? Or a desire to retard the advancement
of radio technology?
Whatever their reason is for
using the "Big Lie" technique, it won't work in
this case, because it is too easy now for USA hams
to go to the source
of true facts about bandwidth
limits. That source is: the FCC rules on the
web.
The best way to understand the FCC rules about
ham radio is to
read the FCC rules, footnotes,
tables, orders, definitions, specifications,
and
FCC opinions. I acknowledge that not everyone is
quite as
enthusiastic about reading this exciting
material as I am. So, perhaps it
will help to
point out the parts of the tome that are pertinent
to this
discussion. Turn your hymnals to Part 97 :)
- The FCC rules contain a
table of frequency bands
in paragraph (c) of "§97.305 Authorized emission
types."
- In that §97.305 table, one can see "Standards" that
apply
to each sub-band or segment of a ham band.
These little details are the key
to understanding.
Some Notes apply to certain sub-bands but not
others.
Here are the important things to look for:
- Observe that
"Footnote (2)" can be found in
the "Phone/Image sub-bands" but Footnote(2)
cannot be found in the "Data/RTTY sub-bands"!
- The text of this
important Standard (2) is
found in:
"§97.307 Emission standards"
paragraph (f) .
Here is the full text of §97.307 (f) (2) -
" No
non-phone emission shall exceed the
bandwidth of a communications quality
phone
emission of the same modulation type. The
total bandwidth of an
independent sideband
emission (having B as the first symbol), or
a
multiplexed image and phone emission, shall
not exceed that of a
communications quality
A3E emission."
The main types of "non-phone
emissions" this
bandwidth limit applies to, only in the
"phone/image
subbands are:
1. Image content (such as video or photo)
2. FAX image
(such as drawings or documents)
The FCC rules define what a "Phone"
signal is.
It includes speech and some other things, such
as selective
calling and controlling tones.
The FCC definition of the word "Phone" can
be
found in §97.3(c)(5) Definitions of terms that
are used in Part 97 to
indicate emission types.
So, everything in the Phone/Image sub-bands
that is not "Phone" is considered "Non-Phone".
On an interesting
side note, did you notice...
there is no bandwidth limit for most common
types
of AM and SSB "Phone" signals in the HF bands?
There is a
non-specific limit for "angle modulated"
signals such as FM voice... but
that is a topic
for another discussion.
See you on 20 meters FM
simplex!
73 Bonnie KQ6XA
