Topband: Broadband Inverted L

[Lloyd Berg - N9LB]

In my case, I started out with four radials, great wideband match ~100KHz

When I had some more time and wire, I went to 8 radials, that cut the bandwidth in half, still a good match.

Each chance I had to add more radials, I did.  Each time the bandwidth decreased substantially, but the antenna kept working better with more radials as measured by my success working weaker and more distant stations.

I'm up to 60 radials now, antenna is no longer wideband, but works better than ever.

I figured out that I was "cooking dirt" back in the days that I had only a few radials.  Now it requires a tuner to QSY more that 10 KHz, but again it works so much better.   Examples, 160m worked and confirmed this year, W1AW in all 50 states, Amsterdam Is, Lord Howe Is, S. Cook Is. 

I suggest adding ground radials or a ground screen around the new feed point - as close to the surface as possible, and attach to the previous ground system too.

73

Lloyd - N9LB


-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com]On Behalf Of Joe
Galicic
Sent: Thursday, November 20, 2014 11:11 AM
To: Mike Waters
Cc: List, TopBand
Subject: Re: Topband: Broadband Inverted L


Mike, The antenna feed point terminates at a four foot ground rod and then I am running a number 14 wire from that ground rod to my existing radial field. That run is about 40 feet. The radial field consists of 3 8 foot ground rods and nearly 2000 feet of wire spread out over my entire front and back yard. I didn’t want to run "new" radials over top of the existing so that's why I did what I did. I am measuring SWR from the shack end of the feed line. My old L was only 35 foot vertical. I thought 65 foot vertical would be much better but sometimes the old L hears and transmits better by a couple S units depending on where the station is of course. So I think something is off? Hopefully I didn’t build myself an accidental dummy load? -Joe 

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

From: "Mike Waters" <mikewate at gmail.com> 
To: "Joe Galicic" <galicic at comcast.net> 
Cc: "List, TopBand" <topband at contesting.com> 
Sent: Thursday, November 20, 2014 11:17:16 AM 
Subject: Re: Topband: Broadband Inverted L 

It sure IS broadbanded. Couple of questions: 

On Thu, Nov 20, 2014 at 10:11 AM, Joe Galicic < galicic at comcast.net > wrote: 


The ground is connected to the existing ground system for the old L. 



Can you describe this? 


<blockquote>
I get a 1.1 SWR reading from 1.8 to 1.9 before it moves up to 1.3 and slightly higher to 2.0. The antenna seems to be working OK (relative to the old L). This seems awfully broad banded? 

</blockquote>


Where are you measuring the SWR? At the feedpoint or at the end of the 125' coax? 

73, Mike 
www.w0btu.com 

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