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  1. #1
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    Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    I need some recommendations regarding the kind of performance I can expect from various gains of omnidirectional wifi antennas that could be attached to a wifi extender (the extender has detachable antennas). I want to use the extender to supply wifi to a building by picking up a 2.4 GHz wifi (incoming) signal from a neighboring building that is about 300 feet away. I want to have the antennas preferably be inside and be simple omnidirectional antennas. There is a some foliage between the buildings, but there is generally pretty good "line of sight" between the buildings.

    I am presently already extending the 2.4 GHz signal to the distant building using a NETGEAR WiFi Range Extender EX3700 which has two single move-able rods on either side of the extender housing (in a kind of rabbit ear arrangement). These rods are not removable. I think these rods are two 3dBi omnidirectional monopole antennas. (I am assuming these two rods are not acting as a single dipole antenna.) This Netgear EX3700 extender is mounted in a window from which you can see the building that is the source for the 2.4 GHz signal. This Netgear EX3700 extender works pretty well most of the time, but it cannot pick up the incoming signal when it rains. In good (not raining) weather, the indicator lights sometimes indicate that the incoming signal is "good" (green light), sometimes fair (amber light), but often the incoming signal is "poor" (red light), but I still get use-able internet even when the signal is "poor". But, as I said, when it rains, and occasionally at other times, I get no incoming signal (light is not even red, it is "off") and there is no use-able internet.

    I recently bought a new different extender that only extends the 2.4 GHz signal (an Ampedwireless SR10000) that has two removable omni-directional 5 dBi antennas, and I need antenna recommendations as to how best improve the connection between the buildings. It seems to me that a higher gain antenna would improve the signal transfer. I think the new extender has higher power (specifically multiple 600 mW transmitters) than the Netgear extender I am already using (I think 50 mW, but am not sure). But more power at the extender amplifier(s), it seems to me, would probably not improve the situation much, since the main problem is the poor/zero incoming signal, when it rains, etc. Increasing the strength of the wifi 2.4 GHz signal at the source (in the other building) that produces the 2.4 GHz incoming signal is not an option.

    QUESTIONS:

    Can anybody recommend how much gain I need for one or two indoor omni-directional antennas attached to the new SR10000 extender to achieve a reliable connection between the buildings even when it rains? (I think I can put the new extender in more or less the same position near the window as the Netgear EX3700 I am presently using.)

    Do you think the 5dBi antennas that came with the new SR10000 extender will be sufficient to achieve that reliable connection between buildings that I am looking for?

    Should I replace one or both of the antennas on the new SR 10000 extender?

    If I replace one or both 5dBi antennas on the new SR10000 extender, what gain antenna(s) should I use as replacement(s)?

    Any other comments would be welcomed.

    Thank you,

    A.
    Last edited by AmateurDIYAntenna; 4th September 2019 at 07:31.

  2. #2
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    First establish whether the rain problem is due to atmospheric conditions or the change in wall material absorbing the signal. If it is the latter (it probably is) the only real solution is to mount the antenna outside the building. That in itself will give you a huge signal increase. I find here the biggest drop in signal when it rains is the damp layer on the outside of the wall rather than the field strength dropping.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Quote Originally Posted by AmateurDIYAntenna View Post
    and I need antenna recommendations as to how best improve the connection between the buildings.
    Use a point to point wifi bridge with a truely directional antenna. The omnidirectional antennas are by design limited in gain, a directional antenna is more suited for the link between two buildings.



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  4. #4
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Quote Originally Posted by betwixt View Post
    First establish whether the rain problem is due to atmospheric conditions or the change in wall material absorbing the signal. If it is the latter (it probably is) the only real solution is to mount the antenna outside the building. That in itself will give you a huge signal increase. I find here the biggest drop in signal when it rains is the damp layer on the outside of the wall rather than the field strength dropping.

    Brian.
    Thanks for your reply Brian. The only real structures between the signal source building and the Netgear extender antenna I am presently using are glass windows: a house kitchen window in which the extender is mounted and a porch window in a glassed in porch. The signal source building is clearly visible from the kitchen window that the extender is mounted in. For this reason I question the validity of the theory that signal strength is decreasing due to a change in wall material due to rain. But perhaps I do not fully understand the theory? If you think that the theory could still be a factor, please explain why.

    The new Ampedwireless extender I want to try has removable antennas that connect to the extender through Female RP SMA connectors, see Figure 2 in Wikipedia article here.

    If I were to mount the antenna outside, what type of coaxial cable (e.g., RG 174/U? or RG6?) would you use to connect the outdoor antenna to the extender?

    I presently have some small diameter coax cable (that I think may be RG 174/U) that has connectors that fit the connectors on the Ampedwireless extender.

    Would you mount both extender antennas outside or just one?

    (As you remember, there are Amazon links to pages describing details of each of the two extenders mentioned in this post in my first post.)

    Thank you,

    A.

    - - - Updated - - -

    Quote Originally Posted by volker@muehlhaus View Post
    Use a point to point wifi bridge with a truely directional antenna. The omnidirectional antennas are by design limited in gain, a directional antenna is more suited for the link between two buildings.

    Thanks Volker,

    The idea of using a directional antenna had occurred to me, in fact I tried to make a Yagi antenna as described in my first ever thread on this forum, see here . In addition to the fact that my homemade version does not work too well, I began to think of other reasons not to use a Yagi. These reasons are (1) I am already getting pretty good performance with the 3dBi omnidirectional antennas described in my first post, so I thought that I just need some marginal improvement in antenna gain to have good performance (2) I am afraid that the return transmitted signal from my extender back in the direction the signal source building might be unnecessarily strong and could cause interference. And I do not want to annoy the kind neighbor who is kindly letting us piggy back off his internet connection and (3) a directional antenna, such as a Yagi, might be unnecessarily large.

    QUESTIONS: Do you (or others) have any comments about my reasons given above?

    Can you or others recommend an online calculator for use in constructing a (directional) home made Yagi antenna?

    I may try a better home made construction of a Yagi antenna again. Several people on this forum have mentioned the VK5DJ Yagi calculator for home made construction here and I have been able to download it and get it to work. It says that people have used it to make 2.4 GHz wifi antennas, but it says that the calculator is preferably for lower frequencies.

    Thank you,

    A.
    Last edited by AmateurDIYAntenna; 5th September 2019 at 02:30.



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  5. #5
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    I know that looks a bit ugly, but a coffee-can antenna for 2.4GHz is the simplest directive antenna (with proved good performances) that you can get for low cost.
    On the net you can find a lot of information how to make it:

    https://en.wikipedia.org/wiki/Cantenna
    https://www.turnpoint.net/wireless/cantennahowto.html
    https://blog.jgc.org/2012/02/long-ra...from-illy.html



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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Quote Originally Posted by vfone View Post
    I know that looks a bit ugly, but a coffee-can antenna for 2.4GHz is the simplest directive antenna (with proved good performances) that you can get for low cost.
    On the net you can find a lot of information how to make it:

    https://en.wikipedia.org/wiki/Cantenna
    https://www.turnpoint.net/wireless/cantennahowto.html
    https://blog.jgc.org/2012/02/long-ra...from-illy.html
    Thanks vfone,

    Does this antenna have advantages over a Yagi?

    In terms of gain?

    In terms of size?

    In terms of ease of building?

    I have seen some people essentially combining both concepts: placing a Yagi with fewer elements in a parabolic reflector to increase range & gain.

    A.



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  7. #7
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Using a parabol for 300 feet WiFi link sounds like overkill. Industry standard directional flat antennas mounted outside the buildings should work well, if line of sight can be achieved.


    1 members found this post helpful.

  8. #8
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Gain of a coffee-can antenna is about 8dBd, which is equivalent with the gain of a (good) Yagi antenna with 5 elements.
    Size of the two antennas are pretty similar.
    Coffee-can antenna is easier to design and to build.
    From my experience Yagi antennas built for frequencies higher than about 1.8GHz, are not working very well. Or at least are not such simple to design compared to lower frequencies Yagi antennas.

    Here you can find some antenna calculators, at least to give you some idea about dimensions:
    https://www.changpuak.ch/electronics/cantenna.php
    https://www.changpuak.ch/electronics...enna_DL6WU.php


    1 members found this post helpful.

  9. #9
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    Quote Originally Posted by vfone View Post
    Gain of a coffee-can antenna is about 8dBd, which is equivalent with the gain of a (good) Yagi antenna with 5 elements.
    Size of the two antennas are pretty similar.
    Coffee-can antenna is easier to design and to build.
    From my experience Yagi antennas built for frequencies higher than about 1.8GHz, are not working very well. Or at least are not such simple to design compared to lower frequencies Yagi antennas.

    Here you can find some antenna calculators, at least to give you some idea about dimensions:
    https://www.changpuak.ch/electronics/cantenna.php
    https://www.changpuak.ch/electronics...enna_DL6WU.php
    Thanks vfone,

    I will think about a cantenna instead of a Yagi. My wireless extender has a female RP- SMA input (wikipedia link) for each detachable antenna, it looks like the N connector in the homemade Cantenna post above at link may fit a pigtail that is RG58 cable. If it is RG58 cable, I would have to use an adapter to go from RG58 to an SMA connector that fits the female RP-SMA input. I already have a coaxial cable that has a compatible RJ-SMA connector. The coaxial cable is about 0.109 inches in outside diameter. It might be RG-174/U.

    Do you know the size of the cable that will fit the N connector in the Cantenna link above?

    Edited Addition added later: It looks like there are several "n-type male connector to rp-sma female antenna pigtail cable" for sale at places like Amazon, see, e.g., see Amazon link so I will likely have to buy one of those pigtails.

    Thanks,

    A.

    - - - Updated - - -

    Quote Originally Posted by FvM View Post
    Using a parabol for 300 feet WiFi link sounds like overkill. Industry standard directional flat antennas mounted outside the buildings should work well, if line of sight can be achieved.
    Thanks FvM, I agree about the overkill.

    A.
    Last edited by AmateurDIYAntenna; 11th September 2019 at 01:41.



  10. #10
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    Re: Recommendation needed for gain of antenna for a 2.4 GHz wifi extender

    RG58 and RG174 are very bad coax cables to use at 2.4GHz.
    Cheap RG316 from any Chinese vendor is better:

    https://www.aliexpress.com/item/3282...chweb201603_55

    ...and use SMA-connector instead of N-connector...is more convenient:

    https://www.aliexpress.com/item/3300...chweb201603_55



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