Discone Antenna

[raggedyanne]

Does anyone have the formulae for creating the Discone Antenna ?

[WhiteHare]

The disc should have an overall diameter of 0.7 times a quarter wavelength of the antenna's lowest frequency.

[emjay]

Hmm... why consider a fundamentally very wide band design when the entire ISM band of interest is relatively narrow?

[raggedyanne]

I visited an ex royal navy communications officer named Rolley (Rolee?) who showed me a double discone antenna that operates in 700-1Ghz band. I jotted down as much information as i could but i lost the paper with the cones and discs formula    .

[raggedyanne]

@Whitehair  Do you know the pitch angle for the cone skirting to centre tap ?

[WhiteHare]

What exactly is it that you're wanting to do? 

[raggedyanne]

Trish sent me an email with directions thankyou Trish 

http://www.changpuak.ch/electronics/calc_11.php

[raggedyanne]

I want to build a dual discone one upside down for 928+ & one the right way up for 918+ , the discone i saw and was told about equalises the frequency , cross phase something something, what you get is a discone that operates at 923 give or take a few mhz due to stratospheric conditions. Which are beyond my current comprehension. You lose penetration below the horizon (for some complicated jargon) and gain sensitivity just below peak. When Rolley returns from Bali i will ask him to explain it in a clear and comprehensible manner.

It has to be mounted 6-8mtrs above ground.

[WhiteHare]

Sounds like a lot of work.  What problem are you having for which that type of antenna is the best solution?  i.e. why are you wanting to do that?

[raggedyanne]

Experimentation!