Re: [IRCA] Short antenna radials

[Stephen Airy <pianoplayer88key@xxxxxxxxx>]

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

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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
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