Hi Hop rates below 1,000 per second are far more common in simple systems than anything faster than that. At VHF, you are looking at a everybody being within one hop of each other. That makes the idea of a GPS based code start fairly reasonable.
Bob On Feb 23, 2011, at 5:03 AM, Hal Murray wrote: > > [email protected] said: >> I think GPS can help by using it to control the transmitter and to set the >> receiver frequencies but the "phase" of the frequency hop clock is >> determined by the time of flight of the signal, something a receiver can't >> know in advance > > Right. But how big is the search space? > > I think that depends on how fast you are hopping and the max distance you > consider reasonable. > > A mile is 5000 ns or 5 microsecond. If you hop every ms there are 200 miles > per slot. If you hop every 100 ms there are 20,000 miles per slot. > > If I pick a max distance of 1000 miles, that's 5 ms. > > If you are off by half a slot, that will be 3dB down in the digital world. > It would probably be pretty ugly in the audio world, but it would be easy to > tune with a knob. > > > Actually, you can know the distance in advance for some games. Suppose I'm > going for the low power record from point X to point Y that are line of > sight. ... > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
