Weather and other factors finally conspired to allow me to work on my portable dipole. The tune on it went way out on 40m after the top section of the squid pole snapped. A quick consult with an old friend and it was suggested that ground effect plays a larger part in dipole function than I was aware. He suggested shortening the legs if the dipole by up to a metre! Bearing in mind that my previous experience was with higher frequencies (11m and above) I thought this was quite excessive. I kept shortening to instruction and found that with a feed point at 5.4m and the legs of the inverted V terminating at .75m above ground level, it had to shorten the legs by 1.2m.
Now I’m aware of this it will be easier to tune antennas in the field simply by doubling the wires back on themselves and using a little insulation tape or, if a semi-permanent fix is required, then a cable tie or two.
The next part will be tuning the links.
Thanks to Chris, VK6FDKR, for the chat 🙂