HF Antenna Choice for new block

[VK4ADC]

I have built a multi-band dipole arrangement like KK4DVs in the past, using a similar spacing wire to wire ( 4" / 100mm)  and the greatest issue is that the wires are too close and the interaction while tuning each dipole is enormous.

My current multi-wire dipole set(s) arrangement is a hang-down style.  The lowest frequency dipole set supports the next lowest by allowing it to hang down below it. The next band hangs from it etc.. and you can adjust the hang-down connection distances to set the amount of droop for each dipole set.  The ends have 100mm spacing to the wire above and a tensioning arrangement to keep this end spacer basically vertical.  Mine are made from 3mm stainless steel wire (so no stretch) and the wire goes through the hole in an egg insulator and is then clamped back along the incoming wire with a 3mm wire grip.   The S/S wire is not trimmed off at all during trimming to frequency - only the wire grip(s) are released and the wire foldback is adjusted, also resetting the hang-down point as needed.

You must start with the lowest frequency (the supporting dipole set) and then work up in frequency (so hanging sets) as you tune the antenna at the final working height.  The values available from my web page ( https://www.vk4adc.com/web/hf-projects/4...na-lengths ) will give you a good idea as to how much to adjust the wire fold-back length once you have measured an initial resonant frequency for any particular dipole set.

By adjusting for more dipole droop (ie. spacing) , the interaction is reduced band by band.

A final note is that select which bands you want dipole sets for with care.  Do NOT pick directly ODD-harmonically related ones.  Don't forget that dipoles will work at odd multiples also.

So picking 160 / 80 / 40 / 30 is ok  (even multiples) but avoid 40 / 20 / 15 (mix of odd and even) as the tuning interaction makes it hard to solve.

For odd plus even go to trapped dipole arrangements.