[Antennas] RE: shortening a dipole

2003年10月20日 16:43:26 -0500

My understanding is that as a general rule, leaving the loading coils 
near the ends of the antenna should be more efficient. However the 
coils will have to be larger (more turns) as you move away from the 
center and toward the ends. You could also try adding capacity hats on 
the ends to make it look longer. I'm not sure what your setup looks 
like, you should use ladder line if possible if you are trying to make 
an 'all band antenna' out of this thing. Otherwise you will probably be 
looking at some pretty substantial line losses. If you have to use 
coax, you might be better off with traps so the match is decent on the 
various bands. Your milage may vary and others will say that I don't 
know what I am talking about so....take it for what it is worth.
73
-Pete
-----Original Message-----
From: "Hart Engel" <[email protected]>
To: [email protected]
Date: 2003年10月20日 17:18:13 -0400
Subject: [Antennas] RE: shortening a dipole
> Here is my current situation:
>> At present I have a half wave dipole cut to 40M band which I use as
> well on 
> 20M with a roller inductor antenna tuner.
>> Due to the restricted length of the roof I have done the following:
>> Each leg of the dipole is cut to 10M, then I took half of each leg
> [5M] and 
> wrapped it around some pvc pipe and mounted that on the end of each
> leg and 
> tied it to a pole on either end of the roof.
>> My question is: If I put the coils in the middle of each leg will
> that 
> radiate better than if I leave the coils at the end of each leg? or
> does it 
> not matter in this case?
>> As you can tell I have a limited space to stretch a dipole and would
> like to 
> get the best bang for the buck as they say. My rig has only 10, 15,
> 20, 40, 
> 160M on it.
> If you have any suggestions about improving my design let me know.
>> Hart
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