Fan dipoles are the easiest multi-band antenna you may wish to have a go at.
Surprise surprise. I was astonished that a cobweb isn’t as bad as I thought it was, certainly in software modelling.
Check it out.
A G5RV is really a doublet, using the feedline to transform (automagically) some pretty nasty impedances to a suitable impedance for coax.
I explain this here:
I’ve discussed this before. 40m band quarter-wave does resonate on 15m.
But is it worth it?
An inverted L is just like a vertical apart from the fact that instead of going straight up (like a tuned quarter-wave), it turns 90 degrees somewhere.
I discuss this in this video:
I’ve recently “made” a 4-element Yagi in software for my YouTube channel which should give a great match to 50 ohms.
If you’re into MMANA software modeling, here’s the file:
NOTE: This is a ZIP file because my Content Management System doesn’t like files ending in MMA. By all means have your Virus Scanner check this Zip file. There is only one file inside this ZIP. Just the MMANA file.
Here’s a new one that you wouldn’t read in the books.
I’m seriously hammering the 40m band here in Cornwall and have tuned the vertical antenna so that the whole of 40m SSB is almost 1:1 swr, certainly from 7.05 through to 7.1Mhz. Over the last few days though, I’ve noticed that the tuning might change over a few hours to give me some serious SWR headaches. Enough to force me at one point to fold back the top of the element by 70cms.
It took me a while to track down what was happening but it turns out that when the tide is in, the vertical is effectively closer to the salt water ground and requires to be shorter than when the tide has been out for a while, long enough for the salt water to drain out the sand and reduce the salt water table by probably 15 to 20 feet or so.