(OLD - By Request) Making a shortened 40m Vertical - DX Commander Rapide (2021)

2 years ago
24

If you have a tree or a spare pole, you can make this. Less than 7m height. But with a COIL for 40m but no 30m element.

Cut your elements this long:

10m 2.65m
12m 3.04m
15m 3.21m
17m 3.81m
20m 4.78
40m 10.03

For every band (not 40m) create a 6cm loop and secure with electrical tape (don't add 6cm to the cut, just create it after cutting)

40m Region 1 (7.00 to 7.200 MHz) Wrap 14 turns of wire just below the white band on a DX Commander pole (that's about 24cm up from the base) then continue to the top of the pole and come back down 60cm. This assumes your pole is 6.5m long.

40m Region 2 (say you need 7.200 to 7.300 MHz) then wrap 13 turns of wire just below the white band on the pole (again.. about 24cm up from the base) then continue to top and come back down 130cm. This assumes your pole is 6.5m long

Fine tuning can be made by cutting or adding wire to the fold-back element at the very top. Bear in mind that each turn of the coil is around 220 kHz change. So if your best SWR is at 7.22MHz, removing one turn will centre you at 7.00MHz.

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