Dual band discone antenna

[bolotzwi]

Trying to design a dual-band (Band A: 20 MHz-180 MHz, Band B: 500 MHz - 3000 MHz) discone antenna for IED supression. I have managed to design a discone for Band B achieving a VSWR < 2.5. Any ideas on how i can make the discone work for band A?

The antenna i'm trying to design is similar to the one found on this link Link

 

[VEBill]

This popped up in a search:

http://ma.kaist.ac.kr/conference/34.pdf

 

[khiggler]

20 mhz discone size needs 1/6 Lambda or 8 foot wires, or a triangular flag, metallized, attached to the discone top. There is no Magic, you need large size. 20-3000Mhz continuous should be the goal. Your needs are too wideband for any tuned device with a magical solution. you could use part of the vehicle possibly. The 20 Mhz gain in the link sounds too low. A transformer 4:1 or higher can help at the low end. 20 Mhz gain for a 0.03 Lambda antenna requires a 25 foot groundplane. Without big groundlanes it would be -20 dbi gain.
I see in their specs,

http://atecorp.com/atecorp/media/pdfs/data-sheets/ARA-Technologies-SAS-2-A_Datasheet.pdf

gain is -25 dBi at 20 Mhz, so Marketing is alive and well. They have optional amplifiers. Maybe marketing used them to pretend gain at 20 mhz is -5 dBi, liars.