Timeline for Beamwidth of omni-directional antenna with gain
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 3, 2019 at 20:10 | comment | added | Marcus Müller | @MikeWaters heh, but my comment did! ;) | |
| May 3, 2019 at 19:55 | comment | added | Mike Waters | @MarcusMüller This comment didn't mention that. :-) | |
| May 3, 2019 at 19:50 | comment | added | Marcus Müller | @MikeWaters difference is that amateurs on Arecibo are allowed to make use of that gain – if you're in Europe, and not a ham, and you attach a 6dBi antenna to your 20 dBm WiFi AP, you legally must reduce TX power by 6 dB, no? | |
| May 3, 2019 at 19:44 | comment | added | Mike Waters | @MarcusMüller Respectfully, that's incorrect. A high-gain antenna at only one end improves both the transmitted signal and the received signal. That's why -for example- the Arecibo radio telescope's 1000 ft. dish antenna allows hams with hand-held 5W FM HTs and their short "rubber duck" antennas to communicate with it via moonbounce (EME). (FYI, the information on that site stating that these were not two-way contacts is incorrect. Among many other sources, a long-time ham who has visited there many times heard this from the techs there. | |
| May 3, 2019 at 18:23 | comment | added | Marcus Müller | That goes to say that a single high-gain antenna onshore and a low-gain antenna aboard will probably not be much better than two low-gain antennas; after all, wifi needs the bidirectional communication. About a MIMO AP: that thing will inherently have antenna directivity × array directivity as directivity, and that is as good as getting a larger antenna, but unlike that, automatically finds the right direction, at least when communication without the array factor (i.e. as if you had a single antenna) still allows for basic detection. That's really the limiting factor here. | |
| May 3, 2019 at 18:16 | comment | added | Marcus Müller | notice that if you're operating that wifi in an amateur radio fashion, you might (assuming typical legislation, no idea where OP is) use rather arbitrarily high-gain antenna systems. However, Europe for example severily restricts EIRP of ISM operation – ie. by adding gain, you reduce the maximum power your transmitter might emit by the same amount, which means that in transmit direction, getting a higher-gain antenna than the default has no advantage – in RX, it does. | |
| May 2, 2019 at 12:14 | comment | added | Brian K1LI | @PhilFrost-W8II Good question, Phil. It doesn't seem as though this would provide much benefit unless the signal was right on the margin of the link budget. Especially since the signal is 3dB down at the extremes of mast travel away from the horizon. | |
| May 2, 2019 at 12:11 | comment | added | Phil Frost - W8II | I wonder if the gain of such an antenna is a net benefit in practice over what you'd get from a good AP with 6 simple dipole antennas. | |
| May 2, 2019 at 11:48 | history | answered | Brian K1LI | CC BY-SA 4.0 |