Someone asked me about ham radio antennas today, built one out of scrap parts to give them. Radio antennas are easier in metric. ðĪ
Fancy 3D printed parts are not necessary.
This is from the "practically free" school of antenna builders. (Random spool of wire acquired somewhere for $1, scrap pieces of PVC from out in the yard, and the antenna connector off an old broken CB radio that would have otherwise e-wasted).
The cheapest version of these you see for sale are around $50. The "tactical version" will cost you $460 (in camo and with fancy carrying case and fancy 3D printed antenna wire holders). ð
(I make more contacts on my el-cheapo free antennas than people who buy any "tactical antenna" ever will).
They teach you the "English system" on antenna calculations in the US.
468 / Frequency = half wave dipole in feet
Then multiple by 12 for inches, divide by two for each side blah blah blah
In meters, 142.5 / Frequency = half wave dipole... but it corresponds to the band names.
In meters, for a 10 meter dipole at 28.500... you need an antenna that is 5.000 meters (half wave of 10 meters). ð That's WAY EASIER.
20 meters at 14.250Mhz? 14.250/142.5 = 10 meter half wave dipole.
@ai6yr I know people (Ben knows the same people) who get totally bent out of shape when I tell students to ignore all of those idiotic formulae. (Is Stu on Mastodon? I don't know...)
I don't care what system of measurement people use-they are ALL arbitrary, period. But MIXING systems is the very picture if stupidity.
We name Ham bands in meters. So do the calculations in meters, in your head, or on your fingers. Yes, Home Depot sells metric tape measures.
AI6YR Ben
W6KME