Towertalk
[Top] [All Lists]

Re: [TowerTalk] Concealed antenna issue

To: "Towertalk" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Concealed antenna issue
From: "Tom Osborne" <w7why@verizon.net>
Date: Sun, 07 Dec 2008 17:44:34 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
There was an article that came out some years ago in CQ magazine.

The author made a wire cage around a tree.  It consisted of 4-135 foot 
wires.  The wire went up the tree to the 50 foot level, hooked to an 
insulator.  The remaining 65 feet went out and back down the tree, connected 
to a ring around the tree (where all the wires were connected together).  An 
insulator was placed in the center of the longer wire to pull it out tight.

There were 4 wires like this.  For precise tuning, there were some top hat 
wires at the top laying in the branches.

I tried one and it worked pretty darn good.  It was a lot broader than the 
single wire it replaced.  7

I know, the tree will absorb RF.  But not as bad at the lower freqencies. 
73
Tom W7WHY




Dave,

Before you go overboard with the aluminum, consider a (wire) cage vertical 
supported by the tree. Just run multiple wires up the trunk, bonding them at 
the base and at the top. As for an 1/8 wave vertical, don't rely solely on a 
tuner but rather make it as near a resonant antenna as possible. Perhaps the 
simplest method is to string it up the tree as high as possible and then let 
the remainder slope back towards earth.... an inverted el. The current 
maximum of the antenna is at the bottom anyway so it's a better method than 
center loading a shorter antenna with a coil. Inductive loading is normally 
my last resort as it has the greatest losses, translating to reduced 
efficiency. My preferences are 1: full size, 2: top loaded, 3: center and 
top loaded, 4: center loaded. I don't have anything that is loaded only at 
the base. Again, try the cage vertical and see if additional wire don't 
help. it's still stealthy.

gl,
Jim W5QM

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>