Topband: Inverted L antennas.

[wa3mej at comcast.net]

Jerry, 

  I started with one radial.. and added inductance here the radial connected to the base 

of the antenna.. wish I remembered what valuee I used .. but I dont. then trimmed the radial I had 

pre cut somewhat longer than 1/8 wl..I dont remember if I used an RF sniffer or a clamp on ammeter 

to trim the radial  when you are done each radial will be ballanced to the correct length  and be physically 

1/8th wl long but loaded to 1/4 wl..   These seem to work well.  My problem at the moment is that 

with the new McMansions next to me I now have all kinds of common mode problems.  



Of course it could be some new appliance or device my wife has added to the house.. I still have to 

resolve it. 



Jim 







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


From: "Jerry Keller (K3BZ)" <k3bz at verizon.net> 
To: wa3mej at comcast.net 
Sent: Friday, November 11, 2011 9:23:44 PM 
Subject: Re: Topband: Inverted L antennas. 

Hi, Jim.... W3LPL ought to know!  Very interesting ideas!   I had arrived at 
the conclusion that elevated radials were what I want to try, and certainly 
1/8 wavelength is a lot easier than longer ones.... however, I'm not sure 
what you mean by "1/8 wl long now but they are loaded and tuned to 1/4 wl 
electrical length".... how do you tune 1/8 wave radials to 1/4 wavelength? 

Jerry K3BZ 

-----Original Message----- 
From: wa3mej at comcast.net 
Sent: Friday, November 11, 2011 5:49 PM 
To: topband at contesting.com 
Subject: Re: Topband: Inverted L antennas. 



I use an inverted L here but it goes to within 6 inches of the ground. 
total length is about 160ft 

with about 70 vertical.  I use a homebrew variable cap to match it.  My 
radials are 4 loaded radials that 

are tuned to be electrically 1/4 wl long. 



When I first installed this antenna many years ago it was at the suggestion 
W3LPL.  After installing 

it I got frustrated when everyone else was hearing and working things that I 
could not even hear. 

A call to Frank helped solve some of the problems.. he told me to walk out 
about 6-10 ft from 

the base of the antenna, grab the radial throw it up in the tree about 6 or 
7 ft above the ground. 

Then he told me to disconnect my ground from the base of the antenna. 



20 minutes later I was hearing and working all kinds of europeans to include 
russians. 

Over the years I have made several modifications to the antenna like adding 
an UNUN at 

the feed point to mitigate common mode problems etc. 



The secret is elevated radials and disconnecting the ground at the base of 
the antenna... I only use 

4 radials that are 1/8 wl long now but they are loaded and tuned to 1/4 wl 
electrical length... It works great 



Hope this helps the gentleman that is wanting info on inverted L antenna 
installation. 



Jim WA3MEJ 
_______________________________________________ 
UR RST IS ... ... ..9 QSB QSB - hw? BK