[Antennas] RE: Vertical antenna (14AVQ)

2002年9月20日 01:45:06 -0400

Chris Bonde, VE7HCB, asked:
> To all those who suggested that the antenna that I had 
> given to me was a HyGain 14AVQ/WB were right on.

> The original owner found the book. However, he lost the 
> top cap {sic - capacity hat}. The documentation does not 
> appear to have the dimension of the three spokes forming 
> the top hat. They look like a piece of wire with a loop 
> to put over the top, one above each other, and space each 
> out > 120 degrees. I have some Al wire that I can bend 
> but was wondering what length?

I just measured mine. From the loop to the end, they are 
10 inches. A guess would be about 12 Gauge. Hard-drawn 
aluminum ground wire or welding rod would be suitable. I 
always put galvanized internal star lock washers between 
each loop and the screw holding them to insure good 
contact.
As George, W5YR, noted, they are not very critical. They 
add a little top loading to the antenna. Since you have to 
slide the top section of tubing in or out of the top trap a 
little to tune the antenna on 40 meters, a slight change in 
capacity hat just means a small change in this tuning. If 
you find the antenna will not tune low enough in the band, 
the capacity hat wires can be lengthened a little.
Typically you would start tuning the antenna on 10 meters, 
adjusting the length of the section below the first 
(lowest) trap for the part of the band you operate in. 
Then go to 15 meters and adjust the section between the 
first and second trap. Repeat on 20 meters with the 
section between the second and third trap. Finally tune 
the length of the top section for your favorite spot on 40 
meters. There is often some interaction so you may have to 
repeat this procedure for optimum results.
As others have noted, there were huge numbers of these 
antennas sold. One of the black polyethylene insulating 
caps over one of the traps cracked on my unit. I just 
wrapped it with black, stretchy vinyl electrical tape and 
sprayed it with clear Krylon. It continues to work fine.
 73, Barry WA4VZQ [email protected]