I have no numbers to give, only anecdotal comments. During operation of VP8WWW last week we used one trapped 5-band Yagi (Mosley Mini-33-A WARC) at 25 feet, one trapped vertical (Cushcraft(?) 80-10)
Jim, You seem to be assuming you can't have an acceptable radial field in a suburban backyard. I'm in suburban Chicago and had an available space of only 60' x 40' for my radial field. I centered a H
G'day, <snipo> put up etc. lossy. <snipo> I use a 30 foot vertical with the base 3 feet off the ground on 30M. This is too long on 30M so the vertical is brought onto resonance with a pair of shorten
ground wires, etc. moderately lossy. pretty close, I would be 60-70% wavelength long(so Ballparking it, you'd impedance if Qcoil=400, X in the loading radial array. You're neglecting or ignoring the
Suburban Chicago has bigger backyards than suburban Southern California<grin>. The entire lot is 50x100 ft, and the backyard is, maybe, 20x50 feet. Of course, there's also a front yard of the same ge
Indeed, verticals are the hot ticket for beach locations, but that's a somewhat atypical ground. The radials slope up from the <snip> So yours is basically a "ground plane" vertical... a 1/4 wave (or
the antenna, and, assume you run the the "exposed" something coming out The feedline shield exits the antenna at a point with the full potential of the lower tip of the antenna, and that isn't good.
Check out "Another Way to Look at Vertical Antennas" by Rudy Severns N6LF....QEX March1999 and http://www.iol.ie/~bravo/low_band_antennae.htm 73 John EI7BA Here's an interesting optimization question
-- Original Message -- I have difficulty in understanding or accepting the notion of "ground losses--...wasted power heating the earth, etc..." I have no problem with using a dc, ac, or rf resistance
The reason for ground losses is because the ground is not a perfect conductor. Just like any metal it has some resistance (lots more than any metal), and anytime an electric field interacts with it t
RF propagating through a lossy medium heats it up. Think of 2.5 GHz radio waves hitting that cup of coffee in the microwave. Not quite as you've described it. EM waves (whether light or RF) striking
of "ground meter to measure earth, I dunno! answer them. Well, anytime an EM wave is reflected or absorbed there are charges moving in the media. The same is true for time-varying electric and magne