Hi The one thing that an alternator system had available was *power*. They are fairly efficient and you put lots of horsepower into them. Numbers in the 100's of KW come to mind....
What we're talking about here is more or less a page from the history of radio in the early 1900's. People that were used to the requirements of a VLF system simply didn't believe that a few watts would get very far at "short wave". It took a bunch of crazies to prove them wrong ... Bob On Oct 6, 2010, at 8:30 PM, Magnus Danielson wrote: > On 10/05/2010 11:52 PM, Bob Camp wrote: >> Hi >> >> Ok, the next layer to this onion is the antenna. At 100KC your antenna is >> 35X smaller than it is on 80 meters foot for foot. In other words, your 100' >> tall vertical on 80 equates to a<3 foot tall antenna at 100 KC. QRP on 80 >> with a 3' transmit antenna anybody? Been there done that, not much range at >> all. At VLF forget about transmitting with a horizontal antenna unless you >> are airborne. >> >> It's not just the antenna, the ground counts as well. If you are by the >> seashore that may not be a big deal. If you are inland, prepare to lay many >> very long radials. >> >> ---------- >> >> After that you hit signal to noise. The receivers worked as well as they did >> because they had an enormous signal to work with. There's an amazing amount >> of crud running around down below 200 KHz these days. Even for timing you >> need a lot of signal to get good results. >> >> Bob >> KB8TQ >> >> Ham for way more than 30 years.... > > Well, in the OLD days, Alexanderson extended the antenna using a coil. That's > how the 127 m high antenna towers of Grimeton transmits the 16,7 kHz of 18 km > wavelength signal across the atlantic. The modulation was CW in 80-speed, but > anyway. That transmitter has several interesting features in it for its > time... like feed-forward frequency stabilisation. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.