Hello,

not long time ago i was caught by a doubt, partially solved in my mind, but
i think can be interesting for the folks here reply to a antenna newbie (me)
about newbie questions

The doubt was (and is): a monopole, end feeded, that is 1/4 wave phisical
lenght, is obviously also 1/4 wave electrical lenght, in respect of the
classic "book image" that show the wave travelling (or standing, here i see
different opinions...) cross the monopole just for 1/4 of the full sinewave.
And this in my mind is OK.

Now, how i do treat a 5/4 wave phisical lenght monopole, in respect of
electrical lenght ?? It is even a "1/4 wave configuration" and 1/4 wl
electrical lenght, because the sinewave travelling (or standing) in the
monopole terminate in both cases at 1/4 of the wave, or 5/4 is just 5/4 wl
and 1/4 is 1/4 wl, electrically and phisically ??

Note: i'm wondering about the impedance, not about radation patterns. I'm
aware that radiation patterns are singular in respect of the singular
electrical lenght of the monopole. Or better, that is what i learn, right or
wrong

The second question is about 1/4 wave vs 1/2 wave monopoles. I googled
around, but no one define exactly why "1/2 wave antenna don't need ground
plane". The most technical explanation i found is that due the high
impedance at the feed point, the 1/2 wl antenna don't care about the ground
plane. But i'm not so convicted about this, and a basic explanation of the
1/2 wl "no-ground-needed" theory is appreciated.

Apologize for grammar errors and lenght of the post. Regards and 73.

-.-. --.-, Cristiano, Italy.