[Antennas] Re: Antennas Digest, Vol 11, Issue 17

[Pastor/KC1DI]

-------Original Message-------
 
From: fkamp at comcast.net
Date: 12/31/04 09:44:16
To: W0OXJ
Cc: antennas at mailman.qth.net
Subject: Re: [Antennas] Re: Antennas Digest, Vol 11, Issue 17
 
 
W0OXJ wrote:
>
> I believe since you are using balanced feed line and will, of course, use
a
> tuner this problem will be taken care of by the tuner.I would make my
> radials the same length as the radiator to keep the antenna balanced.It
> should work just fine.
>
 
 
Yes, the tuner should take care of any matching problems. However, I
wanted to keep the electrical length of the antenna as close to a
quarter wavelength as possible to improve its efficiency. That was
when I started wondering about top loading. I only have 26 feet of
tubing which is fine for 30 meters and higher frequencies. It would
have been nice to top load the thing and get it be an electrical quarter
wavelength for 40 meters. Then, since I want to guy it at the center, I
began wondering if maybe center loading would get me electrical length I
needed for 40 meters.
 
I think that was just wishful thinking, but not being sure about how
much deviation from top loading I could get away with and still get
results, I had to ask.
 
In retrospect, seems a silly question. Now it is going to be insulated,
non-conductive guys and a horizontal, 26 foot top wire working against a
counterpoise. An inverted-L.
 
That should pretty well tap me out as far as usable antenna space. I
already have a 80/40 meter trap dipole, a four element tri-band beam,
and a 40 meter right angle full wave loop. I guess I could be concerned
about interaction between these antennas. I have a corner lot but it
still is in the suburbs and not all that large a plot of land.
 
Regards,
Frank Kamp
K5DKZ

Hi all

Actually the 26 foot (I'd go with about 22 ft. ) .. if you are feeding a
vertical radiator with open wire.  and expect good results on say 40 through
10 meters you do not want to make the vertical so that it is much longer
than 5/8 wave at the hightest frequency you plan on operating.  Once you
start to approach 3/4 wave the radiation angle goes high and you will have
an effective clound warmer which would be ok if you only want local stuff. 
In my experience 22 to 24 feet works great 40 through 10 m .. 33 feet of
course will work but it presents an increasing angale of radiation as you
raise the frequence 33 feet is almost a full wave on 10 meters and thus
would not be a good dx antenna on that band .. it also will not work well on
15m for dx.  but would be resonable on 40 through 20 or 17 meters.  you have
to decide what your goal is.. 40meters or an all round good vertical. for 40
through 10m ... if the later forget the top loading and go with something in
the area of 18 to 24 feet.  With open wire it's been a good performer for me
here... mine by the way was mounted at 35 feet and had only two equal
radials. the same 22 feet as the radiator. 
good luck and hpy New Year.
73 Dave KC1DI

 


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