Topband: Are stacked verticals feasible?

[Charlie Cunningham]

Well, some quick mental arithmetic suggests to me that 12' is approx. 0.025
wavelength at 160 and 6' would be approx. 0.0125 wavelength. Pretty tight
coupling it seems to me. - even if we double those fractions for 80m! Thus
far, I don't think I've seen any indication of what the height of the tower
is?

Charlie, K4OTV

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of N1BUG
Sent: Friday, September 06, 2013 10:16 PM
To: topband at contesting.com
Subject: Re: Topband: Are stacked verticals feasible?

On 09/06/2013 09:26 AM, ZR wrote:
> I would think that at 6-12' spacing from the tower it would minimize
interaction on 160 or 80?

I don't know, Carl. I'll leave it to the experts. What I do know is 
I have made several attempts to erect a vertical for 80 meters near 
my 160 meter tower, using the same radial system. At 10 foot spacing 
from the tower, the base resistance of an 80 meter quarter wave 
vertical was less than 5 ohms. That to me suggests significant 
interaction with the tower. At 5 foot spacing the base resistance 
was less than 2 ohms! I don't have the data handy but I seem to 
recall having to adjust the length considerably from a quarter 
wavelength to cancel a reactive component.

73,
Paul N1BUG
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Topband Reflector