Hi The main point is: If you are looking at a VLF system, phase matters a lot. If your objective is a 100 ns @ 1 second sort of accuracy, you need a very stable phase. At 100 KHz, you are looking at 3.6 degrees of phase shift. Go down to 60 KHz and you are right at 2 degrees. Head to Omega sort of frequencies and it just gets worse.
If you are trying to be “as good as” GPS / GNSS, this is still an order of magnitude (or more) away from the goal …. Since fairly normal propagation effects can get you into “which cycle am I on?”, antenna effects are *not* the dominant issue. Toss in things like skywave and …. yikes …. Bob > On Aug 8, 2020, at 4:15 PM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> Same basic issue, lots of weird interactions and a need to keep the signal >> very precise. Not as easy as it might seem. > > What does "precise" mean in that context? > > I'm not an antenna-nut. Can an antenna miss-match change anything other than > the amplitude? > > How do you automatically tune something like that? The manual way would to > twist the knob while watching a meter. If the meter goes down, you are going > the wrong way. If it goes up, keep going until it starts going down, then > back up to the peak you just passed. > > How do you even know that it needs tuning? Can you measure something > accurately enough? If so, what? > > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
