” You can shorten a vertical antenna by using a loading coil. This online calculator tells you how the amount of inductance your loading coil will need to have.” For further info see this link.
“An approaching Grand Solar Minimum is gaining evermore support. Even NASA appears to be on-board, with their recent SC25 prediction — though, predictably, they stay clear of the implications.
NASA’s forecast for the next solar cycle (25) reveals it will be the weakest of the last 200 years.
The maximum of this next cycle — measured in terms of sunspot number, a standard measure of solar activity level — could be 30 to 50% lower than the most recent one”.
The agency’s results show that the next cycle will start in 2020 and reach its maximum in 2025: For further info see this link.