We will compare the short whip antenna that comes with the adaptor to our hi-gain antenna and to the built-in laptop WiFi.
WiFi AP access point BELL083 transmits in the 2.4 and 5GHz frequency ranges. Laptop placed 10m (30ft) distant behind metal furnace. Survey showed this to be a local point of poor reception, an RF shadow.
Built-in LaptopTablets and laptops fit antennas into the casings and screens. This is a Dell laptop with a Qualcom wireless interface. Scan results with -53dBm. Still a working signal. We explain decibels, later.
Point the arrow marks directly at the AP WiFi access point. Looks good. -45dBm. Compared to the built-in WiFi this is almost 8 times the signal.
As expected, poor reception. -57dBm. Compared to built-in WiFi about one quarter of the strength. Our antenna obtains its boost by being weak in the opposing direction.
In between pointing at AP and pointing directly away. We're getting about the same as the built-in at -51dBm. I think strong reflections from the side are affecting our signal.
Named like the little whip in horse racing. Provided with the USB wifi dongle. Already more sensitive than the built-in WiFi device. Maybe just having a 100mm metal antenna is 3dB double power of the built in?
In case you are wondering what happens with no antenna. -81dBm is a very weak signal. My computer sees the WiFi access point but cannot connect.
Radio frequency connections use coaxial cable, a conductor wire is in the middle of a conducting tube co-axial. All of the connectors and adaptors we need are type SMA. Some are male connectors with a metal pin, some are female connectors that match. Some are screw threaded and some have a spinning ferule ring that screws tight.
BOM Bill of MaterialsThese 4 items fit together to work. Be careful ordering according to the list above. Vendors offer many combinations that will be close but not compatible.
Never force a connector. Use a magnifier to see the connecting pin and socket. Align carefully.
Hi-GainFully assembled. It works like the old yagi outdoor television antennas. Radio waves catch on the metal in our antenna board and are amplified by resonance.
Wikipedia uses this graphic for directional antenna radiation patterns. Our antenna is more powerful in one direction and more sensitive to signals from that same direction.
This antenna amplifies our signal by about 10 decibels. 3dB means a signal has doubled, -3dB means it is halved. Our antenna should give about 2 x 2 x 2 = 8 times the transmitted strength and 8 times the sensitivity in one direction.
dBm is a power measurement comparing what we are getting to 1 mW milliwatt of power. Laser pointers have 5mW of visible light. Our measurements, here, are in microwatts.
UWB ultra wide band means it should give the same performance for 2.4GHz WiFi and 5GHz. TEM transverse electromagnetic is a kind of radio wave. The same antenna is available in prettier casings.
ConclusionIn the same room you will get areas of better and poorer reception. USB wifi dongles receive a stronger signal than laptops or desktops with miniature internal cards. The flat directional antenna does even better but you have to point it in the right direction.
Remember to disconnect the internal WiFi on your laptop to use this new external USB connection.
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