Close, but not quite

Well the 40m dipole (top dipole only, haven’t done the rest) is up! Although it is 1:1 swr on 6.625MHz, not 7.10MHz as calculated..

Thankfully I left a fair bit of overlap (3%, 30ish cm) incase I needed to lengthen it.. with 35cm per side (70cm total) added to the length, it is now 1:1 at 6.480MHz. Ahh of course, it needs to be shorter! Now, 35cm lengthening (per side) made it 0.145MHz lower. I want it 0.475MHz higher than the starting point.. which would make it 3.28*35cm which I want to shorten each end by? That is 1.14 metres per end?!?! That seems a little short?! And MMANA-GAL says it should be horrid! But we’ll give it a try 😉

Ok, it gets down 1.05:1 at 7.290MHz.. Hrrrm! Let’s add 40cm to the length and see if we can get it closer to 7.1 😉

Ok! measured it to 75cm longer than original (so 10.91m per side), and it’s now 1:1 at 7.05MHz. Woo!

Seems to work quite nicely on 15m as well.. we’ll see how we go on PSK31 on 40m and 15m tonight 🙂

Published by Damien Gardner

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