Modification of 3x sector antennas

Question

Modification of 3x sector antennas

granbycools (Aeronautics)

(OP)

18 Aug 14 03:32

Hello everybody,

I have a question concerning a modification of 3x 900 MHz 13 dBi 120 Degree Sector Panel Antennas, which I have removed from their actual radomes.
Inside each radome the antenna consists of a aluminium sheet metal part with 4 actual antennas part, which I would like to rearrange onto a triangular sheet metal part where 4 actual antenna parts of each 900 MHz 13 dBi 120 Degree Sector Panel Antennas are placed on one side of the triangle.
My question is if I am going to have interference trouble between the 3x antenna sides if the distance and size of the aluminium sheet metal construction between the antennas is reduced? Could anybody think of other problems which might occur?

Best Regards,
granbycools

VEBill (Military) · Answer 1 · 2014-08-18 07:54:52

The panel behind the phased array of four dipole elements is part of the antenna; it's a reflector surface. It's normally spaced a bit less than one-quarter lambda behind the driven elements. It's a key part of the antenna design. You can't change it without impacting various aspects of the antenna system performance (impedance, directivity).

Disclaimer: the wording of your explanation is such that it's difficult to be certain that I've understood your intent. It's inherently difficult to describe in words, so you might need to post images or sketches.

IRstuff (Aerospace) · Answer 2 · 2014-08-18 09:12:21

$ does not go into 3 evenly. Note that each "sector" is going responsible for 90° coverage; there is overlap between sectors to eliminate holidays.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

VEBill (Military) · Answer 3 · 2014-08-18 10:12:58

I assumed that the four are an array of four elements. Normally four dipoles spaced 'above' a flat reflector plate. Making a single panel.

And the three are the three panels, aimed 120 degrees apart.

This is an assumption.

Higgler (Electrical) · Answer 4 · 2014-09-05 17:45:29

those are pretty high gains, 10 dB are 60x60 degree beamwiths. Show a pic or data of the antennas. In general higher gain antennas can be placed next to each other without problem, low gain ones are really touchy.
For a system to work, you need to have system requirements. List them with antenna parameters or pics of antennas.
Plan on absorber to help out if patterns are ugly.

Come Join Us!

Posting Guidelines

Modification of 3x sector antennas