Rob <[email protected]> wrote: > [email protected] <[email protected]> wrote: >> Rob <[email protected]> wrote: >>> [email protected] <[email protected]> wrote: >>>>> The listeners should enjoy a smooth reception while driving around. >>>>> So of course there should be no time lag between the modulation signals >>>>> of the different transmitters. Experts in the field tell us we should >>>>> be within 12us. >>>> >>>> Unless I fat fingered the calculator, that means the difference in distance >>>> between transmitters relative to the receiver can be no more than 3.6 km. >>>> >>>> 300 meters per microsecond; it is the law... >>> >>> The goal is not to have 12us difference in arrival time, but to be >>> within 12us for transmission time. >> >> What good does that do you? >> >> And regarding "smooth reception while driving around", have you ever heard >> of multipath or the capture effect? > > Well, smooth reception must be explained as "communication is possible", > not with the HIFI quality expected from a broadcast station. > > What I mean is that you can drive around and receive the signal all over > the place, even when you drive out of range of one transmitter into the > range of the next. It works perfectly when the capture effect results > in reception of one transmitter, and in the area where two transmitters > are equal in strength it requires suitable synchronization to still have > good communication.
Picket fencing makes it irrelevant. > I did not come up with the 12us figure, I would have guessed it a bit > higher. The figure comes from different experts in the field. The > people that designed and deployed such systems in the world of emergency > services etc. Are you sure that figure is NOT for data communications? Most "emergency services" have voice and data these days. > We can now try it in amateur radio because the advances in technology > have made things like GPSDOs and fast network connections affordable. I don't see where that is relevant to anything here. -- Jim Pennino _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
