Allow me to ballpark engineer a 5/8ths wave 160m vertical supported by tethered weather balloons...
For some of my calculations I'll simply ask google....
Radiator length
http://www.qsl.net/w4sat/five8th.htm
585 / 1.8mhz = 325ft length of vertical radiator
I would like 3 elevated ground radials at 120 degree intervals sooo...
325ft ground * 3 + 325ft vertical = 1300ft of wire required
Lets use 18 gauge bare copper wire for everything. Goggle says 18awg weighs 4.917lbs per 1000ft
(4.917lbs / 1000ft) * 325ft = 1.598025lbs vertical
google says
1.598025lbs = 725 grams
This will be important later...
The balloon should have 3 tethers to keep it somewhat centered above the radial field.
Use Pythagorean theorem to calculate how much guy wire length we need...
sqrt(325ft high^2 + 325ft wide^2) = 460ft * 3 guys = 1380ft of guy wire
Use fishing line because its lightweight
6lbs of fishing line per 900 yards (per amazon)
(6lbs / (900yd * 3ft/yd)) * 1380ft = 3.1lbs
google says
3.1lbs = 1406 grams
725g wire weight + 1406g guy weight = 2131g payload weight
Some site found via google says 1 cubic ft of helium lifts about 28g so...
2131g / 28g/cuft = ~76cuft of helium required
Google says the volume of a sphere thats 76cuft = 5.26ft diameter balloon
Weather balloon sizes are easily available up to 30ft if needed. 8ft seems to be common enough
Grab a 125cuft to 150cuft helium cylinder at the local airgas or welding shop and we can send up our payload + any little LED lights and radar reflectors to let the planes know we're there
Only thing that I'm wondering about is with a 325ft radial field can we run our radios close to the center or do I need 325+ft of coax to get away from the entire antenna?