[Antennas] question regarding dipole

2002年3月18日 14:43:32 -0800

A thought that crosses my mind is that the antenna may need to be
significantly shorter if it's only 8 feet above ground. This may work in
favor of getting it as straight as possible.
Just a thought. 73
Kevin, K7RX
Kevin Nathan, Independent Living Coordinator
Dept. of Services for the Blind 
3411 S. Alaska
Seattle, Wa 98118
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-----Original Message-----
From: Don Havlicek [mailto:[email protected]]
Sent: Monday, March 18, 2002 02:32 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [Antennas] question regarding dipole
Joe,
Is there any way to run the dipole straight across the length of the
deck, and then drop the ends down to make the entire length 1/2-wave?
That would work a lot better than 'lumping' parts of the wire. Each of
those 'lumps' is an inductance that would change the center frequency
and bandwidth of the antenna.
If you have 40' of deck length, that would mean you would have about 13'
'hanging down' at each end .. maybe you could even tie them at some
angle OUTWARD from the deck, putting the entire antenna at about the
same relative height.
Just my thoughts .. shortened antennas are not as efficient as
full-sized antennas.
Don - N8DE
Joe Falcone wrote:
>> Hello: I want to run a dipole for 40 meters, 33 feet for each leg, under
my second story deck. I was going to use insulated wire and staple the
wire to the underside of
> the
> supports of the deck. Purpose of the antenna is just to hook up to when I
am on the deck to work some 100 watt CW.
>> I am going to fit the 66 feet of dipole into 40 feet by simply running the
wire in a pattern like this _|~~|__|~~|________ center
__________|~~|__|~~|__ You get the
> picture. (I made the top lines wavy only because I did not know how to
type them straight. The wire will run in straight lines).
>> My question is: Is there some type of rough rule of thumb on changing the
lenght of the wire if you are going to shorten the total lenght of the area
that the dipole is going
> to fit into, or doesn't it matter? Would I still use the 33 feet? This
antenna will be up about 8 feet from the ground, but the land slopes away
from the house.
>> Thanks, Joe. N8TI
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