Trying my hand at #HAMChallenge #hc19. Multi toot
1/x
What I learnt so far:
- modeling in GUI NEC is a trip back to the 90s UX.
- honestly. it was easier to model write a NEC file by hand
- eventually I automated nec file generation
- 4NEC2 won't reload changes to a file, even after exit, so I had to rename it. Eventually I found out how to do it, which was even more convoluted than renaming each new file iteration
4/x #hc19 Setup 4 - geometrically ideal
I'm not posting the intermediate results right now, the gains are so tiny...
- All radials are equal length and spaced at 𝜏/16 (or 22.5°, or π/8, in case you don't like tau)
- No more gap between them
- The radiator is orthogonal to the ground and exactly λ/4
The vertical lobes are symmetric, but obviously losing the tiny gain facing right, same for the horizontal lobes. You can sort of see the donut being more directive in the previous post.
5/x #hamchallenge #hc19s gonna call it done.
On setup 4, we have:
Z = 55 - j10.8Ω
SWR 1.26 @ 50Ω 14.13 MHz
Radiation eff 24.09%
So, between ideal and most compromised:
- the SWR went up a bit. I wouldn't call the compromised one, 1:1.15 bad, and on the field I can regularly tune it to 1:1 by changing the radiator's length
- the impedance is, as expected from the SWR, worse
- amazing 0.06 radiation eff gains.
I was pretty lazy in placing radials before, but it seems I wasn't lazy enough.
@yo3gnd Don’t forget to include the bot in your toot…
@hamchallenge
@n8dmt
oh whoops. that explains yesterday too!
@hamchallenge one #hc19s please!
Hey @hamchallenge, update on yesterday's #hc19s #hamchallenge didn't quite make it?