linx 433 plannar

[ulianov]

I have reception problems with the linx 433 plannar antenna. I put two of them together in order to not use the ground plane required by them. The main problem is I have to put them in a receiver inside a wall plate, and I am using a not insulated power supply. The closest the antenna is to the wall plate the worse the reception is.

I used a thin 50 omhs coax cable to bring the signal to my circuit but the cable inside the insulation and the ground cable from the coax cable get joined at the antenna. So I really don´t have insulation. I guess that is causing such bad reception.

Any ideas?

You can see the picture of the antenna at

**broken link removed**

 

[JimB]

I am sorry but it is impossible to understand the antenna connection from the photograph.

What is the "wall plate" made from? Metal? That could be your problem.

The receiver is obviously some distance from the antenna, hence the use of coax cable.
Could you not just use a wire antenna, 17 cm long?
That way you have a simple quarter wave antenna which should work OK.

JimB

 

[RadioRon]

Seems to be a follow-on from this old thread:
https://www.electro-tech-online.com/threads/linx-plannar-antenna-433-mhz.33778/

 

[RadioRon]

I also can't see enough details in your photo. Can you please make a better photo showing connection details.

If you are connecting the two antenna pcbs back to back, then you need to connect the coax center conductor to one of the antennas and the coax ground to the other antenna where the center conductor would normally go.

I fear the idea of two antennas back to back is too sensitive to the capacitance of the nearby metal switchbox and so the antenna resonant frequency is being corrupted by this metal nearby. If it were possible for you to re-tune the antenna, then you might be able to do so and adapt but this kind of tuning is difficult. It might be better to use only one planar antenna pcb and attach it to the metal side of the switchbox so that the switchbox side wall is the ground plane. The planar pcb would be parallel to the switch cover plate and mounted in the center of the sidewall edge so that it is furthest away from other sidewalls.