[Antennas] Ground losses in ohms??

[Harvey&Bessie]

Sam Morgan wrote:

> Wile reading the article:
> "Short, Coil-Loaded, Ground-Mounted, Vertical or Slanting Antennas" 
> http://www.smeter.net/antennas/loadcoil.php
>
> There is a program called loadcoil.exe there. which I started to use.
> I tried plugging in the data for my bug catcher, which rests on the 
> tar and gravel, flat, roof of my apartment building.
>
> But not to far into the equations, it ask me for my "ground losses in 
> ohms".
> Duh, before I had run into poor/fair/and good as my options, lots of 
> room for guessing with those terms. Never been asked for a numerical 
> value before.
>
>
> In the article it mentions 2 to 12 ohms for small to large vehicle 
> roofs and then goes in to ground mounted radials. I'm afraid my 
> apartment landlord might just freak out if I tried erecting a 33' (1/4 
> wavelength) vertical to help me measure and then determine the actual 
> feedpoint resistance. It took two and a half years to get the shorty 
> on the roof.  ;-)
>
> So my question to the group is, what would they use for the ohms of 
> resistance of a 12' tall center loaded vertical on 40m, when the 
> ground consists of sixteen 13' long wires in a circle on that tar and 
> gravel roof?
>
I would start with ground losses at 35 ohms for a flat gravel roof. That 
may be too "hopeful." It may run higher than that (up to sever hundred 
ohms) depending on what lies directly under that flat roof.
Harvey/W4TG