Nearly a year ago I added a foil tray between my antenna and the FA Filter… This gave me 5-7x the number of detections, all has been good since.
I need to move the antenna, and looking to improve this. Looking at this antenna: 60cm 1090MHz Antenna for ADS-B | The Pi Hut
)Thanks
Trying to visualize this foil tray arrangement? Outdoors / attic or indoors?
good point:
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)
Thanks
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 have new ground plates to install… Thicker and more uniform in shape.
I was thinking of connecting the one closest to the Pi to the Ground of the House.
I use a $5 steel sheet pan from Walmart as a ground plane. I drilled a hole in the center for the antenna to mount securely.
Thanks for the reply. I do have some new ground plates to install. With access difficult, I just want to get it right.
In this quick diagram, I have a shield over the Pi, this has really helped cut the noise, presumably from the PSU, and the PI itself.
I have the option to install the true ground plate at A or B. Which would be best?
If its correct at A would it matter its installed at 1 or 2.
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.
Thanks will give it a try.
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.
Thanks.
As this is in the loft, the only ground I have access to is the Earth ground of the electrical system.
In the past people have advised against using this as grounding.
My plan was to connect the pi, the metal parts, to ground. This would then ground both of my grounding plates in the diagram shown above.
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.
It looks like you had to eat a couple of pies to make this work. If so, that’s a win!
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