I found one of the best text Guides I have ever seen covering the topic of vertical antennas. Whilst it is aimed at 160 metres, much of it is applicable to all the HF bands. Let me take you to the link so that you can benefit from the excellent information provided.
Vertical Antenna Text Guide
[ Ссылка ]
Ham Radio Store
[ Ссылка ]
Energy Saving Video
[ Ссылка ]
