# Where is the positive and negative on a telescopic antenna?

Where is the positive and negative on a telescopic antenna? The image below (from a previous stack exchange question) shows a dipole antenna's positive and negative.

Can someone please post a similar picture, but for a telescopic antenna which shows where the positive and negative are for a telescopic antenna?

• @user_1818839 Don't write answers in the comment section. You have now made every other answer redundant but OP can not mark it as accepted.
– pipe
May 19 at 13:55
• Isn't it the same thing as your diagram except the one half is imaginary behind a ground plane? May 19 at 14:26

By grounding one end of the half wave dipole antenna shown in the question, one can obtain a quarter wave monopole antenna.

And a whip antenna (including telescopic antenna) is a type of monopole antenna.

So just cover the half of the gif with your hand and you'll get the radiation of a whip (or a telescopic) antenna.

The polarisation changes from horizontal to vertical, though.

Halfway between left and right halves of the $$\1/2 \lambda\$$ dipole is a point in space that has zero electric field. This is shown by the green line in the picture below: -

So, you can discard 50% of the dipole antenna and drive the remaining 50% with respect to a ground-plane (formed from the green line above): -

The above images from this answer with a fuller explanation (and quite possibly where the image in the question came from).

This new antenna is known as a monopole and, a telescopic antenna is a monopole. The ground-plane need not be a full-plane and can be formed by the body of a radio receiver and the presence of a human body (in the case of a walkie talkie) or from a counterpoise like this: -

Image from this useful document on antennas