New discone I am working on and some help..

[Kage]

Building a discone for my SDR radio for common VHF/UHF.

Design is simple using the plans found all over the net and online calculators.
Real simple actually, the disc section on top is suppose to be 1/4 wave times 0.70 in diameter, bottom cone is 1/4 wave wide in diameter and the length of the top disc to bottom of the cone is 1/4 wave. Coax is connected center conductor to disk section, shield to cone. Length of insulator between the disc and cone should be an inch or less.

I opted for 130MHz as the starting frequency and built the thing out of some metal clippings from a tomato garden cage.
Now I know the gain is not really any better than a monopole antenna but the idea is to have wide bandwidth.
Not sure what the upper limit of this would be but I notice the 440 band and above seem a little quiet. Could be just the time I was monitoring.
Supposedly these antennas a the go-to antenna of scanner radio listening and can even be used for transmitting albeit with terrible gain and weird SWR depending on frequency.
You can even add a whip antenna to the top disc to cover lower frequencies than it was designed for to get some extra coverage.

Pic of my contraption so far..


That short cut off tube under the disc will be replaced with a longer conduit tube for mounting.
There comes my first question.. Is it alright to ground the discone and its support together or should they be insulated from one another?
I really hope the latter is not the case because it would be much more convenient having its mount grounded right to the feed point of the antenna.

Second question is simply... Any tips?
This is my first discone antenna. I have built other types of biconical antennas like the bowtie but never a large discone.
More elements are better?
I realize the more elements emulate the solid structure of the cone but not sure how many elements are really required or how they help performance.

Should I build a smaller discone for 400MHz+ coverage and would it outperform this one at the higher frequencies or is this good enough to cover the supposed 10 octaves that discones provide?

Thanks and curious if anyone else here has built one of these.