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Harry36

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Posts posted by Harry36

  2. Posted

    3 hours ago, clanon said:

    without 90 degrees phase shift (at half wave center Feed)...two crossed dipoles are NOT Circular Polarized...

    This is all well and good, but what does this have to do with me? Did I say that's not true? The option that was originally posted by the Admin in the topic is not a circularly polarized antenna.  Without phase-shifting elements in this design it is impossible to obtain circular polarization. This is clear to me. in the initial version it is a regular mimo dipole. Perhaps the admin used a phase shift on the port when modeling. I have nothing to do with this.

  10. Posted

    12 hours ago, Dr. Pepper said:

    I found some motivation and tried to add a balun to the design to see if this works and with some calculation i found a solution:

    Side view (without legs to get a chance to look inside):

    slot 19-28-balun-2.jpg

     

    woks quite good, good broadband behavior and a good gain of 14.6 dBi. Its a bit like a batwing antenna 

    A good start! It remains to choose the sizes to expand the band 1700-2700. Once you do, I’ll give you another good idea.

    1 person likes this

  15. Posted

    18 hours ago, miloudsatdz said:

    What is the tool used for cutting?

     

    Use ordinary metal shears for cutting. use a drawing compass for marking.

    what was recommended to you by the message above applies to cutting ceramic tiles or plastic. when cutting metal with such a tool of metal sheets, very serious injuries can occur. do not use such cutters!

  20. Posted

    On 1/16/2023 at 4:10 PM, jbckdsav said:

    Here my small test similar result.

     

     

    Whatever the shape of the emitters, we still will not get a single phase center for the emitter to place it in the focus of the offset reflector.

    Leaving the focus of the phase center of the antenna will lead to a deviation of the radiation pattern beam from the main direction (this can be seen on the graphs: the beam deviates from the axis), this can be minimized by pressing the emitters to each other.
    as soon as we start to press the emitters to each other, then the isolation between the power ports begins to fall.
    if you carefully consider the article to which you refer, then on the graphs we will see the parameters S12, S13, S14. this is the isolation. she is on the verge of a foul. -10 is very little. the smaller the isolation between the power ports, the more difficult it is for the modem to parse the received signal. this results in slower speeds due to reduced modulation. There is such a document of one fairly authoritative organization in which engineers recommend having an isolation between power ports of at least -15 dB, although they say that it will most likely work at -8.
    how it will work, they do not say. (fig.3)

    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwj29t-_gc_8AhUX6CoKHbbTDhAQFnoECAcQAQ&url=https%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-AN214810_Antenna_Placement_Guidelines_For_2_2_MIMO_WLAN-ApplicationNotes-v03_00-EN.pdf%3FfileId%3D8ac78c8c7cdc391c017d0d27bb9962ec&usg=AOvVaw1Jgfoq-zGhnt_rMzvrDVj7

    well done, nice simulation! but do not repeat the mistakes of other users. for the overall picture in the initial calculation, it is necessary to show other users the graphics:

    1. gain - this will allow you to understand how the antenna behaves in the desired range.

    2. SWR. this gives the concept of a matched antenna in the original band. the SWR graph should be displayed in the range, or a little wider, to show others the margin of the antenna. the graph is displayed from 1, not from 0, as some do. don't make childish mistakes. SWR cannot be less than 1. The output of the graph from 0 is an indicator of the developer's illiteracy.

    3. radiation patterns, at the borders and in the middle of the range. this makes it possible to evaluate the distortion at different frequencies.

    p.s.

    you also need to understand that for different types of offset or direct-focus reflectors, you need to have different amplification of the irradiator.
    for F/D<=0.5, the gain should be about 10 dBi.

    for a ratio of ~=0.7, the gain should be about 12 dBi.

    these parameters are valid for any frequency and this is clearly seen from the factory feeds designed for different types of reflectors.

    good luck ;)

     

    1 person likes this

  21. Posted

    On 9/13/2021 at 4:36 PM, Admin said:

     

    open a video on YouTube, turn on subtitles and turn on auto-translate into English. In fact, the author did not say anything normal in this video. he has very little knowledge. this is a simple seller who does not understand anything about what he sells. in Runet, he is a laughing stock. one of his 28 dBi antennas has already become a meme.

    Screenshot_20230114-130636-551.png

    1 person likes this