The difference between spread spectrum and other systems is the
pseudo-random generating of the frequencies and not frequencies
determined by the data. It was originally done to prevent decoding
without the synchronization code. It is only disallowed under FCC
regulations on that basis. SSB also uses "frequency spreading" as has
already been noted, but the frequencies are determined by the code. That
is why there is no reason not to allow ROS except that technically the
frequencies are independently determined by pseudo-random code
generator. Modify the regulations to limit the bandwidth and require
third-party monitoring and ROS would be legal, but as the regulations
stand, rightly or wrongly, we are required to abide by them. The
petition process with public comment prevents harmful emissions from
being used.
Glad we are at the point you wanted to make. I have spent much to much
time on this FHSS vs regulations issue, so I have to go on to something
else now. The FCC has spoken, and correctly so, and if anyone wants to
petition to change the regulations, they can do so.
73 - Skip KH6TY
rein...@ix.netcom.com wrote:
Hi Skip,
Thanks, we have arrived at the point I wanted to get to,
So lets go a little further on this path, suppose I changed the
tones in a not so random fashion. Like I had a way to generate
tones as I do when I speak or make music or like some of those
synthesizers
or whatever they are, do not know the details exactly, but they
generate tones that make up language that it understandable, with training
would that be spread spectrum?
You say varying the tones is the same as varying the VFO to the
outside world, is that science?
Would it make a difference if feed the balance modulator with 100 Hz
or 2500 Hz. lets switch between to tunes, teletype, is that SS?
If I produce speech it is speech if the tones do not form speech, it
is ss modulation?
Are you seeing that SSB is SS? as A kid I use to build oscillators
I could speak to them, and they would swing, and could hear speach
in a radio, unstability or FM , SS?
Lets get to the core is WSJT spread spectrum and please explain to me
why. I just do not seem to get it... Explain me the physics of it. please
I just like to understand this.
73 Rein W6SZ
-----Original Message-----
>From: KH6TY <kh...@comcast.net <mailto:kh6ty%40comcast.net>>
>Sent: Mar 9, 2010 7:04 PM
>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 a spread spectrum system, similar to
>what is done in the ROS 2200 Hz-wide modes. The tones in a ssb
>transmitter simply generate rf carriers, so varying the tone frequencies
>is no different than varying a vfo frequency as far as the outside world
>sees. The distinction in spread spectrum is the generation of the tone
>frequencies independently of the data. I.e., you first generate a tone
>frequency in a psudo-random manner and then convey intelligence by
>modulating the resulting rf carriers.
>
>73 - Skip KH6TY
>
>
>
>
>Ralph Mowery wrote:
>>
>>
>>
>> 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, then you have a bunch of junk. It will
>> not convey any useful information and probably illeagle in the ham
bands.
>>
>> There must be order to it to convey any useful information.
>>
>>
