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clanon

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Posts posted by clanon

  5. Posted

    I didn't want to make this antenna! The image was laid out as an example. Make a narrowband - no problem! I wanted a broadband antenna from AL. stripes.

    The same you built , BUT with FOLDED dipole DIRECTORS...Directional , high Gain , WIDEBAND

    s-l400.jpgAN220P.jpg

  6. Posted

    "As an example, consider two adjacent ports, both having reflection of -9.5 dB (VSWR=2:1), resulting in EVM=-19.0dB. From the Figure 1, error limits are +1.0/-0.9 dB and ± 6.4°.

    By reducing reflection of one of the ports to -20.8dB (VSWR=1.2:1), corresponding to EVM=-30.3dB, error limits reduce to ±0.3dB and ±1.8°.   It should be emphasized that amplitude and phase errors are exclusive, namely at a frequency where amplitude error peaks, the phase error is minimal and vice versa."

    "The effect of changed output VSWR with non-ideal load VSWR reflected by the system will cause additional amplitude and phase errors."

    PS: we tend to forget that THIS are NO OLD ANALOG RADIOS , Amplitud , PHASE and Frequency are USED for MODULATION (Higher the speed bigger the CONSTELLATION vg : 256QAM) and ALL are adversely affected by VSWR , impedance changes ,etc.You'll notice as a decreased speed due to the need for RE-TRANSMISSION...RXQ in LINUX

  13. Posted

    14 hours ago, Marcello971 said:

    If I understood well, this antenna should have a sufficient gain that I need (18 dBi). 

    I have to create 2 identical antennas with a parabolic disc (1 for TX and 1 for RX). The only think we shoud add in the design is the additional feed since the wirless router has 2 SMA connectors.

    Before to start to build the antennas I will wait the results from the simulation and a confirmation from Adim.

    Please correct me if I said something wrong.

    Thanks 

    if you choose parabolic dish reflector 

    you'll need 

    any good TWO PORTS feed for that dish (mimo 2Tx2Rx REQUIRES two cables , two antennas or one at 90 degrees between two ports) to get FULL SPEED it maight work okay with just ONE cable-port but NOT FULL SPEED  (depends on HOW it was configured , firmware settings)

    1 person likes this

  19. Posted

    shabra , what swarg is saying (i think) is that you should MAKE sure that the base of the MED sees a GND (center of grid) at the SAME point like in the BASE station (telecom antenna) which means HOLDING it from OUTSIDE and BEHIND with the circle (director) pointing in to the GRID...

    And that the lobe of this MED is FAT and goes in two directions (polarizations) meaning that you are spilling some radiation since your reflector (grid) is almost rectangular (Circular would be better to reflect both dipoles) which are at 90 degrees

    33-997-212-04.jpg

    2 people like this

  21. Posted

    if TOLERANCES (diameters on shield , leads , PCBs) are not maintained , impedance would change. I would solder straight from modem , card to antenna , if possible. Keeping distances as short as possible and impedance (cable shape ,curves) as minimum as possible. ALL connectors have loses imho

    2 people like this