Ham Radio Dipole questions?

Question by : Ham Radio Dipole questions?
Is there such thing as a full wave dipole?
Why a half wave dipole is more often used? Is it more efficient?
What about vertical antennas? Can i construct one ?/2 ?/4 or ?/8? Will it be efficient for Rx Tx ?
Whats the difference between radials and counterpoise ?
Thats all!

Best answer:

Answer by ?BobB?
it was discovered in the beginning of radio that the 1/4 wave antenna was the most efficient. If you look at the voltage and current curves you can see why this is.

A dipole is two quarter wave radials, also called a HERTZ antenna.

Radials and counterpoise are the same thing.

Think of a hertz antenna in free space. You have one side of the feed point to one element, the other side of the feed point to the radials, counterpoise. Next, using a Smith Chart, you can plot the voltage and current highs and lows (NULLS).

The radials as well as the radiating element needs to be resonate.

I would suggest a couple books.... one by LB Cebik and the other ANTENNAS by the ARRL.

You should be able to find both at www.arrl.org

additional:

contrary to the mis information you are receiving here... a dipole is a 75 ohm feed, the Z is adjusted by the angle of the feed. 75 ohms is not a bad match! In fact, it is very good.

A dipole can be mounted up and down or left and right. The only difference is the radiation polarization. Horizontal is for distance, the pattern hugs the ground (sky wave does not care). If your target is mobile, most mobile stations are vertical, so the transmitting antenna is also vertical - there are exceptions (one of my HF mobile antennas is a folded over NVIS antenna using mil surplus antenna pieces). Shunt fed towers are vertical polarized, but again, skywave propagation does not care how your antenna is situated.
and in a last resort, www.w5yi.org

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