Total posts : 45366
Gerry wrote I’m not that familiar with this requirement and wonder how many people would want to do this?? – I don’t know enough about it. From what I have read, it is complicated to set up and there is the expense of extra equipment and recurring charges for STL feeds etc.
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An issue about doing this that seems to get overlooked on these boards is the way that the radiation patterns of synced, multiple systems interact with each other, even when they are rather far apart geographically.
The link below leads to a net azimuth pattern plot of two identical Part 15 systems 2 km apart. Both transmitters supply equal and synchronized r-f power to each radiator, and the two radiators are driven in the same r-f phase.
So while this system would have no “zero beat” issues between the two carriers, and the modulation of each transmitter could be of identical phase, amplitude and polarity — the coverage it would provide certainly would be less than desirable.
And if the carriers were not synced on the same exact frequency, then the net radiation pattern would not be stable. The peaks and nulls would be constantly rotating to face different compass directions. Using more than two synced systems can be even worse than shown in this analysis.
Not to discourage anyone from trying this, but knowing a bit about what may result should be useful.
Here is the link (paste it in your browser):
http://i62.photobucket.com/albums/h85/rfry-100/SyncedPart15Systems.gif
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