I've been recently wondering about this myself (short-radial efficiency, or lack thereof), but more from the standpoint of low-power part 15 transmitting setups. One example I'm thinking of is such that the total length of the antenna AND all ground radials is 3 meters, and does it make much difference if you use a base-fed radiator with radials vs a center-fed segmented short dipole without radials. (The rule in 15.219 specifies the antenna, transmission line, and ground lead cannot exceed 3 meters.) There's other scenarios I'm wondering about, but I'll leave them off as I think it's beyond the scope of this list.
As for KFI, I believe the original tower was there long before the industrial complex was built. So, I think there could be ground radials there already, and the new tower was hooked up to them? Or maybe they have another way of grounding it. KFI *is* a few dB weaker at my house than KNX, in spite of being 12 miles closer (99 vs 111). I think it's primarily the partial saltwater path for KNX in my case, though. At a friend's house in Moreno Valley, as well as at my grandma's house in San Gabriel, KFI is considerably stronger, like 10-15 dB. There is a very efficient station that I believe doesn't have ground radials - 1530 KFBK in Sacramento, CA. Also I suspect 1500 KSTP St Paul, MN's daytime site may also not have ground radials, but I'm not totally positive on that one. 73, Stephen ------------------------------ On Fri, Nov 29, 2013 9:28 AM PST Bob Coomler wrote: > > >I happened to be looking at a Google earth view of the KFI transmitting site >(33° 52' 47" N, 118°00' 47" W) which is located smack in the middle of a >commercial/industrial area. I was struck by what a small diameter clear area >there is around the base of the antenna; maybe 150 feet. Just curious how the >resulting short radials could really offer much efficiency? Updates to my >understanding of the situation would be welcomed. :-) > >Bob Coomler >Tucson, AZ >_______________________________________________ >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] > _______________________________________________ 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]
