Top element on discone

[RocketMan1]

What are the advantages or disadvantage of having the top verticle element on a discone, the frequencies I monitor are all in the 150.000 Mhz and above. Thanks

 

[N_Jay]

It makes the antenna not a discone.

It does provide improved performance below the lower cut off on the discone.

 

[Don_Burke]

What are the advantages or disadvantage of having the top verticle element on a discone, the frequencies I monitor are all in the 150.000 Mhz and above. Thanks

The vertical element is intended to extend the low frequency performance of the antenna.

If you do not need the lower frequencies, it just adds to the noise coming down the feedline.

 

[kb2vxa]

Hi Rocket and all,

"If you do not need the lower frequencies, it just adds to the noise coming down the feedline."

EH? Let's straighten this out right now. A discone has no vertical element, a ground plane does. What we have here is a hybrid, a discone for VHF Hi Band and above and a ground plane for VHF Low Band. This necessitates some of the bottom elements being unusually long for a discone, they plus the vertical make up the ground plane. These elements are effectively out of circuit where the discone is concerned, they add nothing, no signal, no noise.

So, the bottom line here is you don't need the extra elements so don't buy them.

PITA How about Secret Squirrels and Receiver Beavers? MMMmmm beaver, tastes like fish with hot sauce, not chicken.

 

[RocketMan1]

Thanks for the replies everyone.

 

[Don_Burke]

EH?

I will type a little more slowly for you.

These elements are effectively out of circuit where the discone is concerned, they add nothing, no signal, no noise.

This would require a miracle of physics. Those elements gather energy whether you want them to or not. For the most part, that is going to be out of band signals, which meets the definition of noise I am familiar with.

So, the bottom line here is you don't need the extra elements so don't buy them.

True enough.