Patrick, What Mike wrote was partially correct, but a full wavelength tower would be efficient.
The problem with towers over 0.5 wavelength is that the tower radiates more and more of the power at higher angles. That power is refracted by the ionosphere back into the groundwave zone, where it causes selective addition and subtraction to the ground wave. During subtractive interference, the carrier cancels more or less, causing the sidebands to be too intense for proper demodulation with the carrier on ordinary AM sets, and so distortion sets in. In fact, I do think some low-power AMs use a co-owned TV tower as a radiator. The rationale here is that the reflected skywave returns at a distance that is already QRMed by co-channel interference. 73 de Charlie At 11:31 PM 2/2/2007 -0800, you wrote: >Mike, > >Thanks. I fiqured there must be a reason no one uses anything over 5/8 >on a tower. In some areas, I am sure a fullwave tower could be used. > >73, > >Patrick > >Patrick Martin >KAVT Reception Manager > >_______________________________________________ >IRCA mailing list >[email protected] >http://montreal.kotalampi.com/mailman/listinfo/irca > >Opinions expressed in messages on this mailing list are those of the >original contributors and do not necessarily reflect the opinion of the >IRCA, its editors, publishing staff, or officers > >For more information: http://www.ircaonline.org > >To Post a message: [email protected] ----- Charles A Taylor, WD4INP Greenville, North Carolina _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
