Im hoping to erect a reasonably large but lightweight temp 60m vertical here
in the near future but need to keep the insulator weight down to the minimum
- I see toothbrushes have been used in the past at the 400W level (?) but Im
going to be around that level and concerned over corona _ive made some
lightweight corona rings up but still concerned. I dont think Im going to be
able to top cap load so looking like something around 365pF and perhaps
>3.5mH to resonant

Any pointers and thouughts - yes its a helium lift

Don't compromise on the section joining the balloon to the wire.  I recall someone hitting the key for the first time and then seeing a puff of smoke and a kite flying unattached towards the French coast.

 

I think with a seriously high vertical the high voltage problems will be minimal. - That's not the case with a small vertical where the end voltages are huge!

 

Good luck!

 

David