Yagi antenna driven element; Wilson WeBoost 301111 700-800-900 Mhz

[kittrav]

It appears to me that the driven element -- a folded dipole? -- on this antenna is electrically connected to the boom through two rivets, in contradiction to my understanding that the driven element of a Yagi is supposed to be electrically isolated from the boom as well as from the reflector and director elements.

My intended use is to monitor several P25 trunked 800 MHz Public Safety Systems, all with sites in roughly the same compass direction and all within 25 miles, albeit with terrain obstructions.

I am using an adapter from the antenna's N connector to SMA, and using a short, thin diameter, coaxial cable to the SMA connector on the receiver.

Can anyone help with an explanation?

 

[dlwtrunked]

It appears to me that the driven element -- a folded dipole? -- on this antenna is electrically connected to the boom through two rivets, in contradiction to my understanding that the driven element of a Yagi is supposed to be electrically isolated from the boom as well as from the reflector and director elements.

My intended use is to monitor several P25 trunked 800 MHView attachment 143995z Public Safety Systems, all with sites in roughly the same compass direction and all within 25 miles, albeit with terrain obstructions.

I am using an adapter from the antenna's N connector to SMA, and using a short, thin diameter, coaxial cable to the SMA connector on the receiver.

Can anyone help with an explanation?

See
Folded Dipole
Go down to

"Two Variations on the Folded Dipole" and read about center-sorted folded dipoles.​

 

[prcguy]

A folded dipole would be insulated from the boom and would be around 200 ohm impedance. The Wilson dipole is grounded in the middle so each half is a folded monopole and the feedpoint resistance should be around 50 ohms. The advantage of this feed is wider bandwidth.

 

[kittrav]

See
Folded Dipole
Go down to

"Two Variations on the Folded Dipole" and read about center-sorted folded dipoles.​

I didn't know math would be involved.

 

[dlwtrunked]

I didn't know math would be involved.

The part I pointed to did not have much (any?) math that I recall. Sort of funny you said that since I have a Ph.D. in mathematics (actually true-Kent State University, 1982), I may not have noticed.

 

[kittrav]

The part I pointed to did not have much (any?) math that I recall. Sort of funny you said that since I have a Ph.D. in mathematics (actually true-Kent State University, 1982), I may not have noticed.

Meant as a humorous comment to the beginning of the site you referenced.

My degree was in theater, stage lighting, but I went on to study EE at Clemson. Partial Differential Equations, Linear Algebra, if I never see another mathematical expression of the "natural number" e raised to the J theta, I'll be content.

 

[dlwtrunked]

See
Folded Dipole
Go down to

"Two Variations on the Folded Dipole" and read about center-sorted folded dipoles.​

Should have been "center shorted dipoles".