Hi John

I can confirm .There is no difference in the transmitted spectrum.
Here some comparing done with DL4YHF's Spectrum Lab

ROS v2.6.1
x's       http://home.broadpark.no/~saanes/bilder/ROS%20v2.6.1_xxx.jpg
Idling   http://home.broadpark.no/~saanes/bilder/ROS%20v2.6.1_idling.jpg

ROS v1.6.2
x's       http://home.broadpark.no/~saanes/bilder/ROS%20v1.6.2_xxx.jpg
Idling   http://home.broadpark.no/~saanes/bilder/ROS%20v1.6.2_idling.jpg

la5vna Steinar




On 06.03.2010 10:00, John B. Stephensen wrote:
> 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 frequency in 
> a pseuorandom sequence. The receiver changes frequencies in the same sequence 
> and the logic used to detect a special tone sequence to obtain 
> synchronization is described in section 5. The amount of spectrum occupied 
> increases by a factor of 8. FHSS is one way to minimize the effects of 
> multipath spread but there are also other techniques that occupy less 
> spectrum.
>
> Note that the author of ROS published a second doucument,"ROS Technical 
> Description", that contains elements of the original but does not mention 
> FHSS and omits any description of how data is mapped to tones. Users 
> comparing the original and later versions of the code haven't seen a 
> difference in the transmitted spectrum. 
>
> 73,
>
>   

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