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USB WiFi Adapter Antenna

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ataradov:
Basically, yes. Avoid pointing pointy end of the antennas at each other, radiation pattern of a dipole antenna is a doughnut with the hole going though the antenna length. Basically vertically pointed antenna would have the best performance for common household uses. But if you need it to get better reception on the second floor with the router on the first floor, for example, then horizontal orientation may be better.

But generally, if you have to rely on the orientation for things to work, you are in a marginal scenario either way.

And the most common reason why there are two of them is for antenna diversity - attempt to cover holes in the radiation pattern of one antenna with another antenna. Most routers today have multiple antenna connectors on the outside of the case for the same reason.

E Kafeman:

--- Quote ---Buy one with a piece of metal rob antenna?  or buy one with a printed antenna?
--- End quote ---
Bananas or apples? A steel wire rod antenna is a single antenna structure. At actual PCB antenna you have two different antennas. A such structure is not replaceable with one steel rod structure.
I dislike this PCB version because PCB dipole design may be ok but the both antenna structures are a bit too close to each other and with same polarization which can reduce coverage area and stability for 802.11n and above as it will reduce diversity gain. How noticeable this effect is depend on a lot of factors including type of room and type house.
Best antenna is an antenna in free space, not hidden behind cables or placed close to a wall behind a computer.
If multiple antennas are supported by WiFi radio, place the antennas at decent distance from each other and with different orientation for best data speed and coverage distance.

A PCB antenna will always have a minor disadvantage relative a wire antenna due to losses in PCB material but it allows for better control over antenna tuning at production and is because of this often better tuned.
It exist antenna-rubbish at market, not designed at all for what promises.They are always "no name".

I have a load of old router WiFi antennas. They do in most cases contain a simple endfeed dualband dipole. They are a good choice to reuse for USB WiFi adapters. as they usually are well tuned and have high efficiency.
Very old router antennas are probably single band 2.4 GHz antennas which not is ideal to use if 5GHz band is going to be used but for 2.4GHz are they still fine and 2.4GHz allows often for better  coverage then 5GHz as waves at 5GHz are easier absorbed.
If long distance coverage is needed outdoor can a directive antenna be a better choice. Indoor in a very reflective environment have directivity less value.
When I use USB WiFi adapters do I often use a short USB extension cable to allow USB adapter to be placed at a more free location, and by then also a more free antenna location for best coverage.

Reduced speed and reduced coverage is not always a problem with radio or antenna for cheap USB WiFi adapters.
These adapters have a tendency to behave better if placed in free space which allows for better cooling, compared to if placed at back of a PC.
USB enclosure is often a bit to small to allow for a good air ventilation and heat dissipation.  If chip is overheated will speed be reduced or chip will die until it have cooled down somewhat.

amishasingh:
Better to choose the one with the bigger antenna, that they will ensure to reach the suitable bands faster and better

cdev:
Amisha, not necessarily!

Such an antenna is going to have a pattern like a squished donut.

It needs to be perfectly vertical to be helpful. So the donut gets squished out to the horizon and is aligned with it. Otherwise the extra gain antenna will be very likely be less helpful than the reference lower gain monopole/rubber duckie as pictured  It all comes down to the packaging and the expected application. A longer antenna will have a more lumpy pattern with lobes most likely shaped like a butterfly's wings. They may not be where you need them. The col linear is a great antenna when its able to be kept perfectly vertical. Then it will concentrate more signal in a perfect belt around itself. at the horizon where the receiver is most likely to be.




--- Quote from: bobcat2000 on May 02, 2021, 10:10:15 pm ---I found the teardown for the printed antenna.

It looks exactly like the drawing.
I am sure it costs less to make compared to the 1 piece metal rod antenna.  They can melt the metal rod to make 10 or 20 of these traces.

It looks like they arrange the metal trace just like the Collinear antenna array.

Interesting!

--- End quote ---

NiHaoMike:
In my experience, the best compact antenna for a wireless adapter is a biquad, lots of gain for the size. Put it on a stand that allows fine adjustments to get the best signal.

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