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clanon

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Posts posted by clanon

  1. Posted · Edited by clanon

    You SHOULD start a NEW topic...

    LOVE HF , the ionosphere bouncing thing...Usually long WHIPS with correcting and load coils (maybe from front bumper side folded to cruise and free to rx or tx in a still)-slow position ...over here...

    but Long wire V and rhomboidals are best for RANGE PS: I could dig some ARRL info ...maybe (the older the better)

  6. Posted

    The lens antenna is an array consisting of 680 rectangular waveguides arranged rotationally symmetrically around the antenna axis. The antenna operates as a concave lens, with an index of refraction n<1, which focuses the satellite signals and a reverse image of the Clark belt is projected at a focal plane behind the antenna. The concave properties of the lens ensures that the received plane waves are focused at one point.

    The phase of the waves is shifted forward in the waveguide, and the properties of the waveguides determine the shift. (Dielectric) There are two Fresnel zones in the antenna and, for each zone, the signal path to the focus is one wavelength longer than the previous one. The result is that all signals transmitted through the antenna reaches the focal point in phase. The circular symmetry of the antenna eases the control of the electromagnetic behaviour and reduces cross polarization.

    The media inside the waveguides is dielectric technical EPS with the effective permittivity S=1,1.(Expanded PolyStyrene) The dielectric makes the extremely thin copper waveguide walls possible with good mechanical robustness and it also allows a more compact construction as compared to air-filled waveguides.

    Satellite signals in a span of 36° can be received, which theoretically allows reception from 18 satellites because the required spacing between consecutive satellites is 2°. The receivers (LNBs) are placed on a focal line behind the antenna. Offset angle reception is of course very important in multi-satellite communication and a graph of the amplitude for different offset angles, at 12.25 GHz for the North American model, is shown in the figure below. The very low side-lobe levels help reduce disturbance from neighbouring satellite reception.

     

    81.jpg

    2 people like this

  9. Posted

    Each wall (red brick) could take 5 db out , glass 2db s(depending on each glass) Cinder blocks (dry) up to 7dbs...You're supposed to rest this from Db of the router...or cover this losses with antenna GAIN...

    Sensitivity is much important than Power (is how good you listen and not how high you SCREAM)

    You could add a reflector on the back of your router...pointing to your area of interest...

    1 person likes this

  10. Posted

    2 hours ago, Carlos said:

    Esta antena fue la que cree pero no veo mejoria sera que esta solo funciona cono receptora por que no aumento la pontencia de la señal

    2 hours ago, Carlos said:

    Esta antena fue la que cree pero no veo mejoria sera que esta solo funciona cono receptora por que no aumento la pontencia de la señal

    RECIPROCITY  is the fact that any ANTENNA (passive NO electronics) (and every antenna) has same conditions on Rx and Tx...Power only could be incremented through amplification (electronics)

    More DBi means you concentrate more of that energy on a smaller ANGLE (and the need to point the antenna) directional...

    Esta es facil y esta cerca de los 16db Lipton modified Bester 15V4

     

    1 person likes this

  15. Posted · Edited by clanon

    19 hours ago, Kledi said:

    Hello guys, thanks for this amazing forum, im in antennas since 1 year but i have some questions!

    Antennas like this, are all grounded? I mean if i put the multimeter to check the conductivity, there is conductivity from the main patch to the reflector, or they are isolated?

     

    6881040.jpg

     

    I need to  build an antenna feed for 2.6ghz lte to put it on my off-set dish,  and also a 1.8ghz..

     

    thanks in advance 

    Usually if you put  a screw o rivet , etc right on a CURRENT MAX. right in the electrical MIDDLE Point (MAX CURRENT -ZERO VOLT) a node (point of zero RF voltage) at their centre, so they can be attached to a conductive metal support at that point without need of insulation, without disturbing their electrical operation (ANY metal or dielectric added to a design...CHANGES all characteristics and it must be simulated again...

    With the added benefit of  LIGHTING PROTECTION if you put the whole thing to GROUND (tower and all)

  16. Posted

    Theoretically  9dbi MAX 1 Patch , 12dbi MAX 2 Patchs , 15dbi 4 Patchs ,  8 patchs should give 18dbi but you need DISTANCE area ,(then box shape  and volume and reflectors directors (more volume)

    on 24 x 20 x 5mm (with PES) foam...(even 20 x 18 x 5mm) works

    LIPTON Panel15v4VMod1b...(bigger volume) and weight ...(more SIDELOBES)

    Marine 4 patchs with director (a pain in the ass to build) ...(more SIDELOBES)

    haven't seen it...

    this  

    gets close but bigger area (and some sidelobes)

    The thing with FA-20 PATCHES is that they get more gain with the FLAPS WINGS...at 30 degrees...(but they are really inductive and we need to correct reactivity Zi)

    Don't forget is a COVER of a Netbook (Intel clamshell Class PC)

    image_13791.jpg

    Captura.JPG

    1 person likes this

  18. Posted · Edited by clanon

    2 hours ago, BradleyAmirl said:

    Anyone here try to add an external antenna to an frs walkie talkie? Just wondering if its possible and if it is how is the best way to do it and does it work good? Thanks

    Any LONGER (more GAIN)antenna (for the Fr of interest , and BW , would get you Longer distances) you should start a Thread on this...(I used to connect two uhf 4w handys close to 20km away) making'em new antennas...