Hi Back in the day, if you hung out for a while in the lobby at Continental Electronics, you would notice a model of an old style transmitter over by one wall. Go over and look a it for a a while and all the usual parts were there. Couple of big tubes, big matching coil insulators here and there. Eventually you would notice this tiny spec down by the bottom of the model … hmmm … wonder what that is?
Eventually one might figure out that the tiny spec was a person. The model was of an Omega transmitter …. Bob > On Aug 7, 2020, at 7:33 PM, jimlux <jim...@earthlink.net> wrote: > > On 8/7/20 4:13 PM, Bill Byrom wrote: >> See this 1961 IRE paper at the NIST website: >> https://tf.nist.gov/general/pdf/2303.pdf >> IRE merged with AIEE in 1963 to form IEEE. >> Figure 7 shows the calculated amplitude transfer of the ground wave signal >> vs frequency and distance. Note that for 100 kHz signals, the ground wave >> signal is reasonably strong at 2,000 miles but lousy at 5,000 miles. >> As this paper notes, the sky wave reflections are delayed, and this delay >> depends on the ionization state of the ionosphere along the propagation >> path. This delay is shown in figure 2. >> Figure 6 shows differences between daytime and nighttime propagation of >> pulsed signals. The received signal is a combination of the ground wave >> signal and one or more skywave signals (which are delayed with respect to >> the ground wave signal). >> -- >> Bill Byrom N5BB > > and such stuff is why Omega worked at VLF frequencies - none of that pesky > skywave - lambda=30km and you're ALWAYS below ionospheric cutoff. Alas, they > made some boneheaded mistakes like making one of the frequencies an exact > multiple of 60Hz. > > There is something positively Tesla-ian about Omega with high power low > frequency transmitters into physically enormous antennas - like the one with > the top hat across the fjord. None of this tiny L-band patch antenna stuff > inside a wristwatch. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
