Topband: Broadband Inverted L

[Tom W8JI]

Hi Joe,

Unfortunately all of that stuff renders any model or bandwidth  prediction 
pretty much meaningless. Two antennas 40 feet apart on 160 are about like 
having two antennas 4 feet apart on 15 meters.

We just have to do the best we can with the space we have, although the 40 
ft long ground wire would always be a bad idea.

You could just open circuit the unused L at the base of the antenna, or 
short circuit the feeder an electrical 1/4 wave away from the unused 
L's..... if they are 1/4 wave long antennas.

At least that would get rid of most of the interaction.

I have to detune all of my stuff around here, even my 80M dipoles 200 feet 
from the 160 antennas cause interaction.

73 Tom




----- Original Message ----- 
From: "Joe Galicic" <galicic at comcast.net>
To: "Tom W8JI" <w8ji at w8ji.com>
Cc: "List, TopBand" <topband at contesting.com>
Sent: Monday, November 24, 2014 3:56 PM
Subject: Re: Topband: Broadband Inverted L


Tom there are many other things in the mix here. Five houses within 30-40 
feet, Hi-Z receive antenna within 10 feet of transmit antennas, three other 
wire antennas sharing the same trees and air space. And yes the old L is 
still there at about 60 feet away. I don’t think I'm the only person in this 
situation however. I will either detune or take down the old L. Thanks for 
your patience! -Joe


----- Original Message -----

From: "Tom W8JI" <w8ji at w8ji.com>
To: "Joe Galicic" <galicic at comcast.net>
Cc: "List, TopBand" <topband at contesting.com>
Sent: Monday, November 24, 2014 3:45:13 PM
Subject: Re: Topband: Broadband Inverted L

>
> I now notice much better receive and transmit performance than before.
> Before I added the radials the old L was louder in certain directions.
> That's not the case any more. The new L is louder now regardless of
> direction. So I'm heading in the right direction. I was able to work 3 new
> DX entities on 160 including Italy with only 100 watts CW. The DX was
> about 1-2 S units louder on the new L.
>
> Thanks for all of the helpful suggestions !! It's not easy trying to put
> up an efficient antenna for 160 on a small lot !
>

Hi Joe,

Do I understand this correctly? You have both inverted L's up only 40 feet
apart, with one of them running directly over a tree??

Unless you are detuning unused antenna, anything you observe is an unknown
mix of things. Are you detuning the unused antenna?

How many other things are in the mix?

If it is just one Inverted L, then how are you comparing levels between
them? You can't compare levels with only one antenna up at a time.

I don't think it is possible to reach conclusions or offer advice about
systems before understanding the entire layout.

73 Tom





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