Colinear antenna

[Elkhunter521]

I love this web site because it offers me an unlimited opportunity to display my ignorance.

 

What is a colinear antenna?

[berkinet]

I had a teacher who used to say, it is not important to know information, just where it can be found.

Googling “wiki collinear antenna” gets you https://en.m.wikipedia.org/wiki/Collinear_antenna_array

 

In any case, the wikipedia explains it much better than I could.

[Elkhunter521]

Your teacher was a wise man (or woman). The best part is I almost understand it.

[n4gix]

I had a teacher who used to say, it is not important to know information, just where it can be found.

I had the same wisdom from one of my teachers six decades ago. I took it to heart wholly and it has served me well, especially when I was a work-study in the university library during my graduate days...

[WRCD400]

It is basically two or more dipole antennas mounted in parallel one above the other such as a Decibel Products antennas. You can see the loops mounted one above the other. Those loops are dipoles. The antenna below is a colinear antenna.

[WRAF213]

By stacking and properly phasing the antennas, you get higher horizontal gain and a narrower lobe in vertical gain (less multipath from ground reflection). Some collinear antennas like the one WRCD400 posted can have electrical downtilt, so just because it resembles a professionally built collinear does not mean it would be of utility for base station use (downtilt antennas cover limited areas close to a high-level site very well).