Is the random or pseudo-random manner of generating the tones or carriers an
essential element of spread-spectrum? If so, and if the aim of using such a
method is not to obfuscate the message but only to provide better immunity to
interference and path variations, would you be any worse off
To: digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
I can't fathom the reason for doing that, but if the tone frequencies
are pseudo-randomly generated and then modulated by either on/off keying
or some other way, you will have
Julian,
By definition, it is SS if the pattern is independently generated from
the data. The original intent of FHSS was to make third-party decoding
impossible without knowledge of the code that generated the tones or
carriers. FCC rules disallow encryption because we are required to
police
Skip.
Thank you for the comprehensive explanation. I understand why ROS is illegal
under your rules.
The point of my question was, if FHSS is illegal, why not simply modify the
mode (which after all is experimental and does not have a large number of
users) to use a non random way of
He did, I guess, when he added a 500Hz-wide mode. The footprint of that
mode indicates it is probably FSK as he tried to claim for the 2200
Hz-wide mode. He says he submitted a technical description to the FCC
but will not release it until he gets an OK. Don't know what to believe
from him
El 10/03/2010 7:57, g4ilo escribió:
What does ROS gain by using SS over another mode that carries the same amount
of data at the same speed using the same bandwidth and the same number of
tones but uses an entirely predictable method of modulation?
Processing gain. Signals correlated with
Jose,
If you were going to design a mode that filled 2200 Hz, but did not use
SS, and was as sensitive as possible in that bandwidth, how would you do
it? It would have to be highly resistant to fast Doppler shift also, but
minimum S/N would be the most important parameter, as it would be
El 10/03/2010 10:51, KH6TY escribió:
Jose,
If you were going to design a mode that filled 2200 Hz, but did not
use SS, and was as sensitive as possible in that bandwidth, how would
you do it?
Tough question. I believe that on HF the best solution so far is Pactor-III
It would have to be
--- In digitalradio@yahoogroups.com, Jose A. Amador ama...@... wrote:
El 10/03/2010 7:57, g4ilo escribió:
What does ROS gain by using SS over another mode that carries the same
amount of data at the same speed using the same bandwidth and the same
number of tones but uses an entirely
Jose A. Amador wrote:
It does not mean that SS is not a predictable modulation method, you
just need to know the key, in the USA, the key must be one of a few
specific codes, and if you don't have the key, security by obscurity
applies.
And the FCC does not consider a code used to
- Original Message
From: rein...@ix.netcom.com rein...@ix.netcom.com
To: digitalradio@yahoogroups.com
Sent: Tue, March 9, 2010 11:51:52 PM
Subject: Re: [digitalradio] Re: Question for experts
Hi Ralph,
You got me again. Indeed the Commission requires that it has to be intelligent
Hello All,
Suppose I would build an transmitter with a x-tal oscillator, lets say
running at 7040.000 Hz
Part of the system was a balanced modulator and just to make sure a
a high quality crystal filter, with a 1:1.05 shape factor, was added
in the driver stages for the final amplifier.
With a
El 09/03/2010 03:55 p.m., rein...@ix.netcom.com escribió:
Hello All,
Suppose I would build an transmitter with a x-tal oscillator, lets say
running at 7040.000 Hz
Part of the system was a balanced modulator and just to make sure a
a high quality crystal filter, with a 1:1.05 shape factor,
Jose,
Oversight, we are certainly not allowed to transmit Music!
73 Rein W6SZ
-Original Message-
From: José A. Amador ama...@electrica.cujae.edu.cu
Sent: Mar 9, 2010 1:26 PM
To: digitalradio@yahoogroups.com
Cc: rein...@ix.netcom.com
Subject: Re: [digitalradio] Re: Question for experts
, 2010 5:15 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
Jose,
Oversight, we are certainly not allowed to transmit Music!
73 Rein W6SZ
-Original Message-
From: José A. Amador ama...@electrica.
mailto:amador%40electrica.cujae.edu.cu
oscillator.
Limited my BW to some 300 Hz
73 Rein W6SZ
-Original Message-
From: José A. Amador ama...@electrica.cujae.edu.cu
Sent: Mar 9, 2010 1:26 PM
To: digitalradio@yahoogroups.com
Cc: rein...@ix.netcom.com
Subject: Re: [digitalradio] Re: Question for experts
El 09/03/2010 03:55 p.m
David,
Agreed, the exception to the rule!
73 Rein W6SZ
-Original Message-
From: David Little dalit...@bellsouth.net
Sent: Mar 9, 2010 2:21 PM
To: digitalradio@yahoogroups.com
Subject: RE: [digitalradio] Re: Question for experts
One exception to that would be if it is part of a NASA
- Original Message
From: rein...@ix.netcom.com rein...@ix.netcom.com
To: digitalradio@yahoogroups.com
Sent: Tue, March 9, 2010 5:11:30 PM
Subject: Re: [digitalradio] Re: Question for experts
Hello Jose,
Multiple Frequency Shift Keying, OK, but you really
did not answer my question
-Original Message-
From: Ralph Mowery ku...@yahoo.com
Sent: Mar 10, 2010 12:25 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
- Original Message
From: rein...@ix.netcom.com rein...@ix.netcom.com
To: digitalradio@yahoogroups.com
Sorry Ralph,
I did not read the header.
3 Rein W6SZ
-Original Message-
From: Ralph Mowery ku...@yahoo.com
Sent: Mar 10, 2010 12:25 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
- Original Message
From: rein...@ix.netcom.com
El 09/03/2010 17:11, rein...@ix.netcom.com escribió:
Hello Jose,
Multiple Frequency Shift Keying, OK, but you really
did not answer my question, I think.
Suppose I replaced the modulation device with a filtered
piano ( no harmonics ) a microphone.
I am serious, trying to find out the
Correct but you still have not answered my question. Indeed If I
use one tone and key it on / off I have a cw transmitter, transmitting
on the VJO frequebcy = or - the audio frequency.
What do I have if I just change the tones in a random fashion?
73 Rein W6SZ
If a total random fashion,
I can't fathom the reason for doing that, but if the tone frequencies
are pseudo-randomly generated and then modulated by either on/off keying
or some other way, you will have a spread spectrum system, similar to
what is done in the ROS 2200 Hz-wide modes. The tones in a ssb
transmitter simply
, 2010 7:04 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
I can't fathom the reason for doing that, but if the tone frequencies
are pseudo-randomly generated and then modulated by either on/off keying
or some other way, you will have a spread spectrum
newsletter informed us, the view of the Commission is.
73 Rein W6SZ
-Original Message-
From: Jose A. Amador ama...@electrica.cujae.edu.cu
Sent: Mar 9, 2010 9:24 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
El 09/03/2010 17:11, rein
-
From: Ralph Mowery ku...@yahoo.com
Sent: Mar 9, 2010 9:52 PM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question for experts
Correct but you still have not answered my question. Indeed If I
use one tone and key it on / off I have a cw transmitter, transmitting
on the VJO
El 09/03/2010 21:15, rein...@ix.netcom.com escribió:
Sorry Ralph,
I did not read the header.
3 Rein W6SZ
-Original Message-
From: Ralph Moweryku...@yahoo.com
Sent: Mar 10, 2010 12:25 AM
To: digitalradio@yahoogroups.com
Subject: Re: [digitalradio] Re: Question
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