What is the difference between wifi antennas?

Question

Antenna

What is the difference between antennas?
There are 2 antennas (TL-ANT2412D and some kind of noun), the first one costs about 30-40 bucks and has 12 dbi, has a massive look and can be installed on the street, but the second one is smaller, like on a regular router and has a price of 10 bucks and 10-15dbi
I can’t understand their differences in any way.
It's not even a matter of specifics, but simply comparisons, the characteristics are often on the side of a cheaper and more compact counterpart.
I need to catch wifi through a 500m field, so I can’t make a decision

Answer 1

it's all about the design of the receiving elements of the antenna.
you need 17...20 dbi and on both sides.
the one that costs 10 bucks - 30 meters from the strength - they usually have skinny wires and a metal sleeve.
The fact is that at frequencies of 2.4 GHz, every tenth of a millimeter of the size of the elements affects - therefore, cheap ones have such a breakdown in amplification.
at 500 m you need a sector antenna - like Nanostation

Answer 2

If you have a penchant for needlework, then spending money on buying a "firm" is optional. An antenna made on the basis of an old dish from satellite TV may turn out to be better than a branded one. But as Alexander

correctly noted , directional antennas must be placed at both ends of the radio link, otherwise the connection will turn out to be one-way. And if your antennas are truly highly directional (and in my photo it’s exactly like that, the width of its radiation pattern is only a few degrees), then you need to aim them more precisely, focusing on the maximum signal using special software .