[TowerTalk] Ground radial question

Jim Brown jim at audiosystemsgroup.com
Wed Dec 26 12:10:09 EST 2007

On Wed, 26 Dec 2007 10:44:47 -0600, Its from Onion wrote:

>My question, would it help if I ran some radials off of the ground
>point at the rod?  

It won't change the way your antenna works at all. It MIGHT improve 
lightning protection -- IF you properly bond it and your station 
equipment to the power system ground. 

>The system is a little noisy and I heard a ham say once that removing
>the ground from the radio helped him, but mmmm?????  don't know about

Not at all surprising. Connecting a radio or antenna system to the 
earth is almost never a solution to noise problems, and can often 
INCREASE noise problems. BUT: It's quite important that antennas and 
equipment be grounded for lightning protection.

Your antenna may be noisy simply because it is so unbalanced. That 
unbalance causes common mode current on the feedline. That common mode 
current will put RF in your shack (and your house), and it will couple 
NOISE from the feedline to the antenna.  

SO: What WOULD help is a serious coaxial choke at the antenna 
feedpoint, but since you're using 450 ohm line, you would need to have 
a small section of coax with the choke between the antenna ahd the 

See http://audiosystemsgroup.com/RFI-Ham.pdf 

for lots of info on these chokes, how they work, why they work, and 
how to build them. Also study the section on what makes a balanced 
antenna, and why virtually ALL ham antennas are un-balanced, even when 
fed with twinlead. 


Jim Brown K9YC

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