[digitalradio] A closer look at ROS]]

[Andre Kesteloot]

Tom,

Essentially,  our (AMRAD) first experiments were in Frequency Hopping  
mode,and we were hopping all over most of the 2 meter band (using  
modified ICOM hand-helds with extra wires all over. :-)

As long as we did not dwell too long on the input  frequency of the  
various repeaters, we did not create (too much) havoc.

Then I started Direct Sequence SS on the 70cm band (see the ARRL SS  
Source book) and there was no detectable interference at all on that  
band.

My experiments were eventually duplicated by James G1PVZ, under the  
watchful eyes of the British Authorities, also without interference,  
as I recall.

All the details of what we were authorized to do, as well as what we  
actually did do, is detailed in the ARRL SS Sourcebook

Hope this helps,

73
André


On Feb 22, 2010, at 16:17, Tom Azlin N4ZPT <n4zpt at cox.net> wrote:

> Hi Andre,
>
> Still does not answer my question. What was the concern at the time
> AMRAD was working SS approvals.  If a signal were inside a 3KHz voice
> grade bandwidth would those original fears be applicable?
>
> I certainly accept that there is no free lunch. that is my favorite
> systems trade comment.
>
> 73, Tom n4zpt
>
> On 2/22/2010 1:54 PM, Andre Kesteloot wrote:
>>
>>
>> Sent from my iPhone (apparent spelling errors are due mainly to the
>> thickness of my index and the size of the iPhone keyboard).
>>
>>
>> On Feb 22, 2010, at 11:31, Tom Azlin N4ZPT <n4zpt at cox.net> wrote:
>>
>>
>>>
>>> Spreading is adding known redundancy otherwise you would not get
>>> spreading gain.
>>>>
>>>>
>>
>> Alas, there is no such thing as a free lunch.
>> You only get spreading "gain" because you first introduced spreading
>> losses.
>> 73
>> André N4ICK
>>
>>
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