Re: Vertical antenna problem

Well it seem that Google has the answer.
I found that lot of people are talking about influence of wire insulation on
velocity factor.
I didn't know that this influence is so big.
I think that the best solution is to cut radial and vertical to length 4.7m.
73 9A4MN Neno


"neno" <nenadBEZSPAMA@xxxxxxxxxxxxxxxx> wrote in message
news:fb8e32$qo1$1@xxxxxxxxxxxxxxxxx
Hello,
I build lambda/4 vertical for 20m (i used the fishing pole).
The vertical and radials are build from insulated wire 2.5 square
millimeters.
I have used formula on internet and Eznec so I cut 5,09meters wire for
vertical and 4 pieces 5.25m wire for radials (i left radials longer so I
can cut them to make fine tuning of antenna).
I wanted minimal SWR on 14.050MHz.
But now I have minimal SWR on 12.800 MHz . :-)
According to Eznec if I short the radials for 2meters (so they will be
long 3.25m) that will rise resonant frequency around 1.2MHz.
But it is not logic to me. So short radials?
Also according to Eznec if I short vertical to 4.7meters and radials to
4.7meters that will also rise resonant frequency arround 1.2MHz.
Could that be that my mistake is that I didn't calculate the velocity
factor for wire.
Maybe i should calculate it because I used single wire instead of aluminum
tube.
Or maybe some surrounding objects are influencing. I have metal mast for
loop antenna 5meters from vertical.
It is easier to cut radials (because I don't have to take down the whole
antenna).
What do You suggest?
To cut only radials to 3.25m or vertical and radials to 4.7m?
What is better?
Just to mentioned that I tuned antenna with tuner and it works great for
DXing.
73 9A4MN Neno



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