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I'm looking for an antenna that can detect the direction of another (transmitting) antenna.

Instead of only getting the signal strength and moving around, or turning a directional antenna around to find the strongest signal direction, I would like to have this antenna point me in the right direction by giving me a readout - it's X degrees clockwise and Y degrees elevation.

At the moment I don't even know what such an antenna would be called so searching the web is not bringing up anything useful.

(I checked the help page and it seemed like this question is appropriate here, but if I'm wrong, just let me know. I'm new here. Thanks.)

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closed as too broad by Bence Kaulics, Daniel Grillo, PeterJ, uint128_t, Dmitry Grigoryev Jun 29 '16 at 8:31

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ turnpoint.net/wireless/cantennahowto.html \$\endgroup\$ – JIm Dearden Jun 28 '16 at 18:58
  • \$\begingroup\$ @ThePhoton Great! You can transform your comment into an answer. (By the way, I was expecting some way using 3 or 4 antennae and measuring which got the signal first. But I guess electronics aren't that accurate.) \$\endgroup\$ – ispiro Jun 28 '16 at 19:12
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    \$\begingroup\$ Due to your specific requirement not to rotate the antenna, you are very close to asking a question about designing a system for what they call "war-driving" to find (open) networks. The legality or morality of such would be questionable. May be you can update your question to include your reasons why you do not want to rotate the antenna. Because an answer already given (cantenna) is probably the cheapest and most effective way to find your "router somewhere in your house", which in itself is suspect as well; that you do not know where your router is... I have answered below as well. \$\endgroup\$ – Edwin van Mierlo Jun 29 '16 at 8:26
  • \$\begingroup\$ @EdwinvanMierlo If you really suspected me of malicious intent - you shouldn't have posted an answer. \$\endgroup\$ – ispiro Jun 29 '16 at 10:15
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    \$\begingroup\$ @KalleMP, A much smaller phased array should be adequate if OP doesn't need milliarcsecond directional precision. Obviously we can only give general answers (as in my post) without more details about the requirements, but I still think we can give useful answers. \$\endgroup\$ – The Photon Jun 30 '16 at 15:52
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If you want to change the direction of an antenna without physically moving it, you can use a phased-array antenna. This means using several antennas and adjusting the phase of the signal at each one so that they produce constructive interference in a preferred direction and destructive interference in other directions. By reciprocity, the same principle can be applied to receiving as to transmitting.

If using a phased array for direction finding, rather than simply sweeping the direction of the antenna, you can use a signal processing algorithm to effectively search all directions simultaneously. Two well-known algorithms for direction finding are MUSIC and ESPRIT.

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I don't even know what such an antenna would be called

Well, it sounds a bit that you want to do a bit of "Radio Direction Finding" which is actually a (radio) sport. Many systems have been invented.

One which is popular, which multiple static antennas to get an azimuth reading for the direction the signal is coming from is called a "Doppler Antenna Array".

Here some info on such.

However these type of systems are usually used with frequencies around 145 MHz or 435 MHz. It would take some re-engineering to make such systems work for 2.4 GHz, and with tolerances which actually would give a useful reading.

Not sure how you would get elevation with a non-rotatable antenna system. Maybe a second Doppler array stacked on top of each other, in theory this could work, but you will have to be carefull in regards to gain patterns which are already elevated for vertical antennas.

HTH

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Directional antenna.

Look up Pringles Tin antenna for WiFi experiments.

https://en.wikipedia.org/wiki/Cantenna

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  • \$\begingroup\$ Thanks. +1 because I did write "Preferably without having to turn the antenna around". But what I'm really looking for is something that can read a direction without having to be turned around. \$\endgroup\$ – ispiro Jun 28 '16 at 19:01
  • \$\begingroup\$ @ispiro You really do like moving the goalposts with your in body edits of the question. \$\endgroup\$ – KalleMP Jun 30 '16 at 6:41
  • \$\begingroup\$ Point taken. I wasn't clear enough. By the way, I did not remove my upvote. You still have a +1 from me. Someone else must have downvoted, and probably did not read my comment. \$\endgroup\$ – ispiro Jun 30 '16 at 10:18

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