The This wikipedia article on vacuum airship contains helpful notes on the concept. The key formula is the weight of air: 1.28g/L

A litre is 10cm^3. I calculate that a disc with 3m radius and 10cm height. So, for example, a vacuum cylinder that was 3m radius and 1m height would theoretically generate a bit over 60 lbs of lift. How can the skin be light and sturdy enough to carry itself and carry light electronics and hold the vacuum. I think about a glider design that has some internal brackin and a set of vacuum pumps on the outer shell that run as needed to regenerate minus pressure or change altitude.

Edit: Problem not mentioned in the link is that the air pressure falls very rapidly with altitude, and the lift from the vacuum decreases proportionately. This is an issue even for the radio tower height. Another point of concern is guarding against malicious shooting – a kevlar underside would add weight. On the plus side, the vacuum pumps could shoot displaced air down which would add lift. Battery power in cables is one possibility. Many have observed how a tethered kite generates force lift from wind, even when it is not moving. A design which stabilized the vehicle while providing an air foil in every direction experiencing wind would be able to harvest energy in that way, in addition to solar. The double skin design mentioned by wiki was a bad thinko as a means of providing structural support, but we can imagine an outer level that is sucking air out of the middle & projecting it down. At some level of vacuum completeness, this design could also be made to draw external air away from the place immediately above the craft, creating a portion of helicopter style lift in addition to the jet & the vacuum buoyancy.

The tensile strength of clear plastic with a thin copper wire in the middle can be very high. The overall, again, is less intrusive than a radio tower but also less durable to extreme sabotage or unanticipated weather events.