[TowerTalk] Anyone use a 120' qso king?

TexasRF at aol.com TexasRF at aol.com
Fri Jan 24 11:38:54 EST 2014

One way of looking at radials with the ends grounded is as a transmission  
line. The radial is one conductor and ground is the other conductor. A 
ground  rod essentially shorts the far end. With a radial length of 1/4 
wavelength, the  short reflects back as very high impedance. High impedance means 
little current  flow into the radial and that is opposite of what is needed.
Even shortened radials will suffer with reduced current flow. 
Bad idea!
Gerald K5GW
In a message dated 1/24/2014 8:28:49 A.M. Pacific Standard Time,  
jim at audiosystemsgroup.com writes:

On  1/23/2014 8:44 AM, Herbert Schonbohm wrote:
> Some would argue that  putting ground rods at the end of radials 
> doesn't really  help.

Right. Really bad idea. We do NOT want current flowing in lossy  earth. 
The function of radials is to SHIELD the antenna from lossy earth  and to 
provide a return for antenna current and the fields the antenna  
produces.  Also, the end of the radial is a high impedance point.  Adding 
a ground rod messes up the current distribution on the radial, and  
increases loss.

> In most cases you can do well, perhaps better  with #12 or #14 THHN 
> insulated wire laying on the ground.  You  will only then need about 
> 90-100 feet for each radial due to the  velocity factor of the wire 
> itself.  If you run out of space due  to your lot size you can run the 
> ends at right angles. It is  important that the ends are not grounded. 
> IMHO what you are trying to  do is cause the ground system currents to 
> travel in those wires  rather than being dissipated in the earth thus 
> improving the system  efficiency. You can pin the wires down with large 
> galvanized nails, ,  pounded into the ground after a single turn around 
> them. (U clips are  also available by the hundred lot from 
> DX-Engineering) Normally after  two weeks the sod will cover them and 
> they will be invisible and  allow the lawn mower to pass over without a 
> snag.

All of this  is very good advice.On-ground radials are as good as buried 
radials -- the  only reason to bury them is to protect them from foot 
traffic. In general,  with on-ground radials, more is better and length 
is not  critical.

73, Jim  K9YC


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