Commercial and military SS systems also use FSK so that not likely alleviate
the problem. The pseudorandom movement of the center frequency is the issue.
Since the object is to prevent intersymbol interference due to multipath
spread, one way around the legal issue is to transmit even symbols on
Any petition should reduce regulation rather than increase its complexity by
continually adding loopholes. ROS is not the only mode that is currently
illegal -- there are single carrier PSK digital modes that U.S. amateurs can't
use because of the baud rate limit. U.S. regulations should be harm
The FCC only requires that a technical description be published:
Sec. 97.309 RTTY and data emission codes.
(a) Where authorized by Sec. Sec. 97.305(c) and 97.307(f) of the
part, an amateur station may transmit a RTTY or data emission using the
following specified digital codes:
(1) Th
If someone sent a letter to the FCC about Chip64 they would get the same
response that the FCC gave for ROS. The FCC only gets involved when someone
complains. I think that they would love to have simpler and less restrictive
rules to enforce. It's the public that opposes the removal of restrict
Convolutional coding and Viterbi decoding may increase the occupied bandwidth
but they also decrease the amount of power required to communicate. In some
cases, like trellis-coded modulation, the bandwidth stays the same even though
the power required decreases by a factor of 2-4. Spread spectru
These modes use interleaving and randomize data values by exclusive-ORing with
a pseudorandom binary sequence. The methods are used in most commerial products
and the FCC and NSA know how to monitor the signals.
The FCCs problem is that the military uses FHSS and DSSS to hide the existance
and
To: digitalradio@yahoogroups.com
Sent: Wednesday, February 24, 2010 03:37 UTC
Subject: Re: [digitalradio] Consensus? Is ROS Legal in US?`
On 02/23/2010 10:22 PM, John B. Stephensen wrote:
> These modes use interleaving and randomize data values by
> exclusive-ORing with a p
In order for amateurs in the U.S. to use any RTTY/data mode other than Baudot,
ASCII or AMTOR over 2FSK they must be able to point to a published technical
specification for the potocol that shows that it is legal. It was condition
that we all agreed to when we were issued a license. When this i
A member of this group contacted the FCC, got a ruling, and published it here.
Just remember that you have no legal defense if the FCC decides to take action.
I keep replying to this stuff because some members of this group could led
others into losing their licenses.
73,
John
KD6OZH
-
] Consensus? Is ROS Legal in US?`
I see you have not idea waht is the meaning of Spread spectrum.
Spread spectrum reduce energy density.
--
De: John B. Stephensen
Para: digitalradio@yahoogroups.com
Enviado
st to see
whether people comply.
73,
John
KD6OZH
- Original Message -
From: Dave Ackrill
To: digitalradio@yahoogroups.com
Sent: Wednesday, February 24, 2010 20:48 UTC
Subject: Re: [digitalradio] Re: Consensus? Is ROS Legal in US?`
John B. Stephensen wrote:
>
A lawyer with an engineering degree would be the best person to interpret FCC
regulations. The ARRL has engineers and lawyers and deals with the FCC so they
are the best source of free advice in the U.S.
73,
John
KD6OZH
- Original Message -
From: Bob John
To: digitalradio@yahoo
CHIP64 is legal above 222 MHz -- they're assuming that the user will notice
that it's spread-spectrum and act accordingly.
73,
John
KD6OZH
- Original Message -
From: jose alberto nieto ros
To: digitalradio@yahoogroups.com
Sent: Wednesday, February 24, 2010 23:30 UTC
Subjec
is legal because is not a SS modulation.
--
De: John B. Stephensen
Para: digitalradio@yahoogroups.com
Enviado: jue,25 febrero, 2010 00:47
Asunto: Re: [digitalradio] Is ROS Documentation Published
The FCC didn't do anything arbitrary or capricious. They read a specification
provided by the author of the software that stated that ROS is a
spread-spectrum mode. They then told the person asking for the FCC's opinion
that they should go by what the author wrote and not use ROS on HF.
The au
A new technical description was published so you should see what it describes
-- fixed start and stop sequences using 16 tones with convolutionally coded
data using 128 tones in between.
73,
John
KD6OZH
- Original Message -
From: Steinar Aanesland
To: digitalradio@yahoogroups.c
The FCC will say that it up to each licensee to check the legality by reading
the new technical specification. Unless someone shows that the spectrum doesn't
match the specification U.S.hams should feel safe using ROS.
73,
John
KD6OZH
- Original Message -
From: Dave Ackrill
To:
Chapter 8 of the 2010 handbook has a short overview of spread-spectrum
techniques that could be applied to either analog or digital modulation. The
original signal cold be anything (BPSK, FSK, FM...) and is phase or frequency
modulated by a pseudorandom sequence in order to spread the signal ove
There is a technical descrption at http://rosmodem.wordpress.com/. I doesn't
describe the start and stop tone sequences or completely describe the mapping
from the convolutional encoder to the 128 tones used for data. However, it's
more compete than some of the technical specifications on the AR
The problem is that the FCC regulations are overly complex and people need a
specialized engineering background to interpret some of them. 99% of the
licensees probably can't interpret every word in the regulations so they ask
for help in this forum when something is not clear.
73,
John
KD6OZH
e ROS signal when
idling
A good portion of the FCC rules is almost cut and paste from ITU standards
which apply worldwide.
--
From: "John B. Stephensen"
Reply-To:
Date: Mon, 1 Mar 2010 01:0
I had no doubt that it would once the document that the FCC requires was
published. Since European hams don't normally read FCC regulations, it might
be useful for the IARU or RSGB to publish an article about U.S. regulations
so this doesn't happen again.
73,
John
KD6OZH
- Original Messag
The document that the author of ROS originally published, "Introduction to ROS:
The Spread Spectrum", contains a good description of frequency-hopping
spread-spectrum (FHSS) techniques. Section 4 describes taking a 250 Hz wide
mode (MFSK16) and spreading it over 2 kHz by shifting the center freq
The HSMM working group never proposed the use of spread spectrum. It was
interested in getting the maximum data rate into limited bandwidths. SS does
the opposite of what the HSMM WG was interested in. It spreads limited amounts
of data over the maximum bandwidth.
The actual proposal was to cre
I assumed that people kept using FSK because paths to Europe can have 20-30 Hz
of Doppler spread.
73,
John
KD6OZH
- Original Message -
From: KH6TY
To: digitalradio@yahoogroups.com
Sent: Tuesday, March 09, 2010 19:08 UTC
Subject: Re: [digitalradio] Re: 1976 FCC - Delete all
The ARRL response was that the final proposal retained the existing automatic
subands.
73,
John
KD6OZH
- Original Message -
>>>When that 1 percent deploys unattended stations that transmit without
first checking to see if the frequency is in use, they can create havoc far
out o
The FCC R&O makes some big changes on HF. It limits the bandwidth of data
transmission to 500 Hz below 30 MHz.. It also states that data and image
transmission were never authorized in the same HF frequency segments so
data
in the phone/image segments seems to be prohibited. Considerable spectr
The FCC R&O makes some big changes on HF. It limits the bandwidth of data
transmission to 500 Hz below 30 MHz.. It also states that data and image
transmission were never authorized in the same HF frequency segments so data
in the phone/image segments seems to be prohibited. Considerable spectrum
c
It would be reasonable to allow switching
between voice, data and image in the phone segment, all using the same
bandwidth. This would cause no interference to adjacent frequencies and is the
essence of regulation by bandwidth.
73,
John
KD6OZH
- Original Message -
From:
I only recently joined this list so here is some
more specific information on 6-meter wideband digital testing.
The ARRL, at the request of the HSMM WG, asked for and
was granted a license to test digital modes up to 200 kHz wide on 6
meters. A goal of 256 kbps was set as this would allow
Even though the license authorized 50.3-50.8 MHz, I stayed away from the AM
calling frequency. The only frequency used so far is 50.7 MHz, so the signal
covers 50.625-50.775 MHz and the FCC occupied bandwidth (-27 dB) is within
50.6-50.8 MHz.
73,
John
KD6OZH
- Original Message -
From
The ARRL told me that any data transmission mode
(defined as computer to computer file transfer) wider than 500 Hz would be
prohibited on all HF bands if the rules changes go into effect. Image
transmission bandwidth is unchanged. They also said that they are working to
convince the FCC to
I specificly asked about Pactor III and was told
that it would be illegal. This is why the ARRL is upset with the
FCC.
73,
John
KD6OZH
- Original Message -
From:
DuBose Walt Civ AETC CONS/LGCA
To: digitalradio@yahoogroups.com
Sent: Tuesday, October 31, 2006 1
The current rules restrict emissions in
various requency segents by tye of information being
transmitted (RTTY, data, phone, image) and usually allow either analog
or digital transmission (this is the second character in the emission
designator).
73,
John
KD6OZH
.
- Original Mes
The problem with NVIS is that there are a lot of
paths over which the transmitted signal can reach the
receiver. When DRM was tested, they measured a 7 ms delay spread in an
equatorial region and I've seen reports published on the Internet showing up to
13 ms. In near-polar regions, there
The key appears to be whether the information is printed immediately or not. In
97.3, RTTY is defined as "Narrow-band direct-printing telegraphy." So text is B
if it is printed or D if it is not printed.
It's interesting that emission types B7W, B8W and B9W (ISB) are still allowed,
so you can
The FCC uses the phrase "quantitized or digital information" in the definitions
in part 2 so anything encoded into discrete levels of amplitude, phase or
frequency is digital.
The definitions in part 97 were probably very clear when they were written. It
looks like they took amateur radio terms
quist
To: digitalradio@yahoogroups.com
Cc: digitalradio@yahoogroups.com
Sent: Wednesday, November 22, 2006 19:49 UTC
Subject: Re: [digitalradio] Re: OFDM data is Emission Designator D1D
John B. Stephensen wrote:
> its orthogonal because the state
> of each subcarrier is indepen
t know)
but that cannot be deduced from the fact that they carry independent
streams of bits.
Rick N6RK
John B. Stephensen wrote:
> I should have said that the subcarriers must be orthogonal because
> Pactor-3 uses each subcarrier to send an independent stream of bits. In
>
The FCC rules provide the following definitions for fax:
Image. Facsimile and television emissions having designators with
A, C, D, F, G, H, J or R as the first symbol; 1, 2 or 3 as the second
symbol; C or F as the third symbol; and emissions having B as the
first symbol; 7, 8 o
The FCC rules provide the following definitions for fax:
Image. Facsimile and television emissions having designators with
A, C, D, F, G, H, J or R as the first symbol; 1, 2 or 3 as the second
symbol; C or F as the third symbol; and emissions having B as the
first symbol; 7, 8 o
Pactor-3 is as legal as it was before the Omnibus R&O, but unless you are
sending a fax it is restricted to the new RTTY/Data segments.
73,
John
KD6OZH
- Original Message -
From: Roger J. Buffington
To: digitalradio@yahoogroups.com
Sent: Wednesday, November 29, 2006 02:03 UTC
If radiated power is not limited, data rate is directly proportional to
bandwidth, but the maximum data rate per kHz depends on the amount of time
(multipath) spreading and amount of frequency (Doppler) spreading. NVIS has
a multipath spread of 6-12 ms and there needs to be a gap between symbols to
Dopper shift increases with ionospheric disturbance and the solar geophysical
reports always show that the effect is more pronounced in northern latitudes. I
don't know a lot about the physics of the ionosphere but I assume that it's for
the same reason the aurora always occurs near the poles. M
The people that could use more bandwidth daily would be the digital SSTV users.
Someday we may be able to mix RTTY, data, image and voice like hams outside the
U.S.
73,
John
KD6OZH
- Original Message -
From: Danny Douglas
To: digitalradio@yahoogroups.com
Sent: Thursday, Nove
Look at http://www.fcc.gov/sptf/reports.html to see what the FCC thinks.
Their
spectrum policy report states:
"As a general proposition, flexibility in spectrum regulation is critical to
improving
access to spectrum. In this context, flexibility means granting both
licensed users
and unlicense
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