Biquad and Grid Reflector

[rana75 4]

Hi Everyone,
I've just built a biquad antenna and it's working fine now, I could reach a target at 500m from my home. However, I'd like to improve its performance, so I may get better internet signal and speed. I've got a 2 halves Parabolic Grid Reflector (approx. 100cm*60cm) but I have no idea, how and where to place the biquad, if I decide to use it as a feed for the grid!
Thanks in advance,
 

[Admin 2729]

,,,show your  Parabolic Grid Reflector...!!!

[rana75 4]

[Admin 2729]

,,,try varying the distance of 355 mm for optimal reception...

 

[clanon 292]

Secondary Reflector (small one with similar angle and shape as MAIN reflector)  is of MOST IMPORTANCE and antenna should be BACKFIRING (looking back) otherwise you're JUST shielding it from back signals...

[Admin 2729]

Clanon, the boy has a biquad antenna...!!!

[rana75 4]

Trevor Marshall suggested two sidelips (up and down) of 20mm, and Andrew McNeil suggested a 30mm one,which one is better?

[Admin 2729]

,,,rana75,show what biquad you have...!!

[clanon 292]

2 hours ago, Admin said:

Clanon, the boy has a biquad antenna...!!!

is goin to be a BIG secondary reflector and Biquads have an almost spherical lobe IIRC (better suited for a DISH )

[clanon 292]

Trevor approach seems the Right on the money!  BUT it's using an OFFSET DISH...No SHADOW from feed and different focus F/D ratio spillage etc,

Edited June 30 by clanon

[rana75 4]

Here is the biquad, with what I'm connecting to you right now. The design is based of the model from martybugs.net website. The refletor dimension is about 154mm*143mm, I did it according to what I have. Everything is still experimental, luckily working but unfortunately with a fairly poor result.

[Admin 2729]

You need something like this....

[rana75 4]

Here is the built that I've just made. I attached the biquad into a PVC pipe, and I drew the coax from inside the pipe. The PVC pipe can slide inside the hole (see the 4th picture below). The last image showed the final work on its stand.
I've got no measuring equipment or anything similar, but just relying on the windows stuffs.
Tell me if there is something to adjust or to correct from my construction.

[rana75 4]

These are what I've got as an improvement, You can see the speed was increasing a little bit.

 

I've been expecting something better, however this is the best I can do and get so far!

[clanon 292]

Use THIS is more PRECISE (PS: also try rotating the tube  gradually to get the POLARIZATION in the SWEET SPOT) Good work!

[rana75 4]

On 30/06/2025 at 1:56 PM, Admin said:

,,,try varying the distance of 355 mm for optimal reception...

 

Can you tell me the max and the min depth of this 355?

 

[Admin 2729]

17 hours ago, rana75 said:

Can you tell me the max and the min depth of this 355?

 

355.....594 mm