Topband: 43’ 80 Meter Vertical

[Rick at dj0ip.de]

I agree with Rick; its better to use 4 top-hat wires.

On my Vertical Antenna page, I originally showed plans for verticals with 2, 3, and 4 top-hat wires.
I now only show the 4-wire version, except for the Inv.-L.

Let's put this in perspective:  for the short pole Bob is using, the top-hat wires are going to be in the neighborhood of 100 ft. long.
So we do need a lot of space for this.

The more top-hat wires, the shorter they need be.  
But try to keep them equally spaced around the pole and at equal heights.

And, if space is an issue, the only solution is a longer pole.
For instance, with the 60 ft. Spiderpole, the 4 top-hat wires are only about 82 ft. long.
And with the 85 ft. Spiderpole, the wires are about 23 ft. long.   (If not for darn HOA's . . . )

With these longer poles, the top-hat wires should not exit from the top; these poles are too thin.
Drop down one segment and connect the top-hat wires there.

73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
May the Sunspots be with Us!

-----Original Message-----
From: Topband <topband-bounces+rick=dj0ip.de at contesting.com> On Behalf Of Richard (Rick) Karlquist
Sent: 11 April 2021 00:35
To: Chortek, Robert L. <Robert.Chortek at berliner.com>; TopBand List <topband at contesting.com>
Subject: Re: Topband: 43’ 80 Meter Vertical


On 4/10/2021 1:16 PM, Chortek, Robert L. wrote:
> Hoping to get some guidance from the antenna gurus here.
> 
> 
> Can someone tell me if I added two top hat wires 16 GA THHN sloping at 45 degrees “about” how long they would need to be to resonate at 3.545 MHZ.
> 
> Bob/AA6VB
> Robert L. Chortek

After SWR, the most overrated goal for ham radio antennas is resonance.  You should use the amount of top loading that maximizes the radiation resistance.  Then put an appropriate reactance in series with the antenna to provide a resistive load to the transmitter at 3545.  The reactance may be turn out to be inductive or capacitive.  You will also want to make the series reactance variable somehow unless you only ever want to operate on 3545.

You would also be advised to use 4 top loading wires instead of just two.  There is a substantial advantage for 4 vs 2.  Beyond
4 top wires (say 8) the benefits aren't worth the trouble.
This is explained by the fact that 4 is the maximum number of top wires that don't couple to each other.

It is also advantageous to pull out the top loading wires to a more gentle slope if you can.

You can use bare aluminum electric fence wire to reduce weight and wind loading on the vertical.


73
Rick N6RK
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