The comment was made that ROS is different from a FFSS mode that
accomplishes the spreading by shifting the VFO frequency. The point is
that in a SSB transmitter, the RF frequency is equal to the suppressed
carrier frequency plus (USB) or minus (LSB) the tone frequency. So it
does not matter how the RF frequency gets moved, either by VFO shift of
a carrier, or by tone shift on a SSB transmitter. Unfortunately, Jose
went to great lengths to establish that ROS is a FHSS mode. He does this
by using different tone frequencies but the result is the same as
shifting a VFO frequency in a traditional FHSS transmitter. The RF is
still shifted according to a pseudo-random code in both cases. To the
observer, there is no difference except perhaps in the degree of
spreading used.
It is just unfortunate that the FCC regulations were undoubtedly written
in order to keep really wide FHSS transmissions from covering all of a
band, and in the aggregate, have a multitude of stations seriously
interfering with many narrow bandwidth modes. By keeping the spreading
within the bandwidth of a SSB phone signal, Jose sidesteps the problem,
but it still takes a clarification, or exemption, or modification, of
the rules as written to make it possible for us to use ROS on HF. In
other words, the FCC could say that as long as the spreading is no wider
than a phone signal, it is legal to use SS on HF, but this would have to
be done in advance of regular use. If not, I could use a SDR with FHSS
capability and spread over 100 KHz for whatever benefit that might bring
and if others did that, seriously interfere with the use of the band by
many other stations on a different base frequency. Since there is lots
of room on UHF compared to HF, FHSS is already legal there and a
reasonable degree of spreading is not of so much importance. This is why
ATV is only allowed on UHF. It is so wide that it takes a wide band to
leave room for others to share and operate.
73 - Skip KH6TY
Tony wrote:
Skip,
> The problem with ROS is that the frequency shift is by a method too
similar to that used in VFO-shifting spread spectrum
> (frequency hopping) transceivers so to the observer, there is no
difference.
Could you elaborate on this please?
Tony -K2MO
----- Original Message -----
From: KH6TY
To: digitalradio@yahoogroups.com
Sent: Sunday, February 21, 2010 10:14 PM
Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for
USA Hams
RF is RF and the FCC does not care how the frequency expansion is
done, whether by VFO shift or supressed carrier tone shift. I am
shocked that Bonnie does not understand that simple principle. For
example, true FSK is done by VFO shift, but FSK is also done on SSB by
tone shift. The result is identical, the only difference being that
the transceiver does not have to be linear with FSK shift, but it does
with tone frequency shift to prevent splatter. The problem with ROS is
that the frequency shift is by a method too similar to that used in
VFO-shifting spread spectrum (frequency hopping) transceivers, so to
the observer, there is no difference. It is the frequency hopping that
makes ROS spread spectrum, and unfortunately, that is against the FCC
regulations. If it were not, there could possibly be spread spectrum
transceivers using tone shifts much wider than an IF bandwidth, even
using soundcards, just like SDR's spectrum displays use. In that case,
more than one voice channel would be taken up for the benefit of the
SS user, to the detriment of adjacent stations, or even those farther
away, if there were no other limitations on bandwidth utilized.
73 - Skip KH6TY
W2XJ wrote:
Bonnie you have a Ham unfriendly addenda. Say what you like but at the
end of the day it is BS.
From: expeditionradio <expeditionra...@yahoo.com>
Reply-To: <digitalradio@yahoogroups.com>
Date: Mon, 22 Feb 2010 01:09:14 -0000
To: <digitalradio@yahoogroups.com>
Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams
Given the fact that ROS Modem has been advertised as Frequency Hopping
Spread Spectrum (FHSS), it may be quite difficult for USA amateur
radio operators to obtain a positive interpretation of rules by FCC to
allow use of ROS on HF without some type of experimental license or
waiver. Otherwise, hams will need an amendment of FCC rules to use it
in USA.
Sadly, this may lead to the early death of ROS among USA hams.
If ROS Modem had simply provided the technical specifications of the
emission, and not called it "Spread Spectrum", there would have been a
chance for it to be easily adopted by Ham Radio operators in USA.
But, the ROS modem designer is rightfully proud of the design, and he
lives in a country that is not bound by FCC rules, and probably had
little or no knowledge of how his advertising might prevent thousands
of hams from using it in USA.
But, as they say, "You cannot un-ring a bell, once it has been rung".
ROS signal can be viewed as a type of FSK, similar to various other
types of n-ary-FSK presently in widespread use by USA hams. The
specific algorithms for signal process and format could simply have
been documented without calling it Frequency Hopping Spread Spectrum
(FHSS). Since it is a narrowband signal (using the FCC and ITU
definitions of narrowband emission = less than 3kHz) within the width
of an SSB passband, it does not fit the traditional FHSS description
as a conventional wideband technique.
It probably would not have been viewed as FHSS under the spirit and
intention of the FCC rules. It doesn't hop the VFO frequency. It
simply FSKs according to a programmable algorithm, and it meets the
infamous 1kHz shift 300 baud rule.
http://www.arrl.org/FandES/field/regulations/news/part97/d-305.html#307f3
This is a typical example of how outdated the present FCC rules are,
keeping USA hams in "TECHNOLOGY JAIL" while the rest of the world's
hams move forward with digital technology. It should come as no
surprise that most of the new ham radio digital modes are not being
developed in USA!
But, for a moment, let's put aside the issue of current FCC
"prohibition" against Spread Spectrum and/or Frequency Hopping Spread
Spectrum, and how it relates to ROS mode. Let's look at "bandwidth".
There is the other issue of "bandwidth" that some misguided USA hams
have brought up here and in other forums related to ROS. Some
superstitious hams seem to erroneously think that there is an
over-reaching "bandwidth limit" in the FCC rules for data/text modes
on HF that might indicate what part of the ham band to operate it or
not operate it.
FACT:
"There is currently no finite bandwidth limit on HF data/text emission
in USA ham bands, except for the sub-band and band edges."
FACT:
"FCC data/text HF rules are still mainly based on "content" of the
emission, not bandwidth."
New SDR radios have the potential to transmit and receive wider
bandwidths than the traditional 3kHz SSB passband. We will see a lot
more development in this area of technology in the future, and a lot
more gray areas of 20th century FCC rules that inhibit innovation and
progress for ham radio HF digital technology in the 21st century.
Several years ago, there was a proposal to FCC to provide regulation
by bandwidth rather than content. However, it failed to be adopted,
and ARRL's petition to limit bandwidth was withdrawn
http://www.arrl.org/news/stories/2007/04/27/101/?nc=1
Thus, USA hams will continue to be in Technology Jail without access
to many new modes in the foreseeable future :(
Best Wishes,
Bonnie Crystal KQ6XA
