I would like mount something more permanent to the mounting bracket with the 4 screws… Howerver this is not the base of the antenna and is about 40mm from the connector…
Or would it be better after the filter?
The second screen seem to help cut noise from the Pi, and its worked very well for 9m… low temp of 23c and High in summer of 63c (if you can call it summer)
Home grown success. FYI…switching power supplies like those used in small format chargers are famous for generating large amounts of noise due to the square wave architecture of the switching supply. Linear transformer supplies are far better.
I would install the ground plate at point 2 which is directly connected to the antenna’s ground. Then connect the other stuff below the plate. The plate will counter any noise.
I’d also be inclined to install it at A because that presents a ground plane for the antenna as it stands, regardless of what’s going on further down. This position will also have the happy side-effect of shielding the receiving elements from the electronics below. Given that it could be mounted such that 1 screws into a structure that forms part of a ground plane, I’d consider 1 part of it and thus deploy a ground plane at that level with good electrical contact with that plate (a short piece of wire with a lug on each attached to a screw and perhaps a locking washer).
Drill a hole in the center of the plate just large enough to fit over the antenna base threads. Then fasten the plate securely with a lock washer and nut. Finally attach the coax. The mast must be grounded as well.
At these frequencies, ground is a misnomer. It can be a DC electric ground, but the wire from the base of the antenna and other parts are many wavelengths away from anything like a RF ground. You already have a ground connection via the coax shield.
And hopefully you can mount the antenna so the top of the antenna is not near any of the metal braces connecting the roof beams and structures. This minimizes the mis-tuning of the antenna and reduces signal loss. Hope all goes well with the system move. Stay safe up there.
Thanks for the reply @astrodeveloper
You advised moving the top of the antenna away from the metal brace on the roof last March.
I have now been able to do this, the antenna is 280mm away from the metal brace at the top of the antenna. It is literally the top 40mm that is on the same horizontal plane. In all other directions its free from obstructions.
I have checked, and there is DC GND from Pi to Antenna Base. Will Try this for now.
PSU is located 2500mm away from the antenna base.
At the weekend hope to install the new ground plate, just waiting on some right-sized washers.
Evening, thought I would report back… Antenna moved and new plates installed. So far the signs are all positive…
All the measures in Graphs1090 have increased by 9-12%
Number of detections at over 200nm have increased a lot, around 50%
Signals now range form -1.3 to - 32dB
Not pretty, but it works.