I would like to extend the edge of my 150cm satellite dish by 40-50cm all around with some aluminium mesh. This does not need to follow the parabolic as it’s job is to reduce ground noise. I have found some metal straps x6 which I have attached at 60 degree intervals all around the rim projecting out centrifugallly from centre of dish by the required extra 40 or 50cm. I would now like to attach plastic piping around the extended perimeter. How long a pipe do I need, what diameter will give me a rigid enough structure to hole the aluminium mesh taught, whilst still giving sufficient bendability to give me a circle around the perimeter? Can you give me links to appropriate pipes sold in UK?
Answer below by ChatGPT 7/6/2026:
For a 150 cm dish with a radial extension of 40-50 cm, the geometry is straightforward:
- Original diameter = 1.5 m
- Original radius = 0.75 m
If you extend:
- 40 cm all around -> new radius = 1.15 m -> new diameter = 2.30 m
- 50 cm all around -> new radius = 1.25 m -> new diameter = 2.50 m
The circumference of your perimeter ring will therefore be:
| Extension | New Diameter | Circumference |
|---|---|---|
| 40 cm | 2.30 m | 7.23 m |
| 50 cm | 2.50 m | 7.85 m |
I would buy at least 9 m of pipe to allow overlap, trimming, and adjustment.
What pipe diameter?
Your six aluminium radial straps are doing most of the structural work. The pipe only needs to:
- Maintain a circular shape.
- Keep the mesh under tension.
- Survive wind loading.
My recommendations:
| Pipe OD | Pros | Cons |
|---|---|---|
| 20 mm MDPE | Very easy to bend | Too floppy for a 2.3-2.5 m ring |
| 25 mm MDPE | Good compromise | May sag slightly in strong winds |
| 32 mm MDPE | Best choice | Slightly harder to bend |
| 40+ mm MDPE | Very rigid | Unnecessarily heavy and difficult to form |
For your application I would use 32 mm MDPE (alkathene) water pipe. It is flexible enough to form a 2.3-2.5 m diameter ring yet stiff enough that the mesh can be pulled reasonably taut. MDPE is designed to be coiled and has a very small minimum bend radius compared with the radius of your extension ring.
The bend radius of a 32 mm MDPE pipe is approximately 800 mm. Your proposed ring has a radius of 1150-1250 mm, so it should form comfortably without kinking.
Alternative that may be better
For maximum stiffness, many radio astronomers use:
- 20 mm or 25 mm aluminium electrical conduit
- 20 mm glass-fibre pole sections
- 25 mm uPVC electrical conduit
rather than water pipe.
However, because your ring is supported every 60 degrees by the six straps, 32 mm MDPE is probably the easiest and cheapest solution.
Suitable UK products
These are the most relevant options from current UK suppliers:
- — sold by Toolstation. A 25 m coil would leave plenty spare for experiments.
- — available through Drainage Superstore.
- — if you decide 25 mm is sufficient.
- — another widely available option.
One further possible suggestion
If the aim is primarily ground-noise reduction rather than aperture increase, you may find it advantageous to make the extension slightly conical (like a shallow “hat brim”) rather than flat. Even a 10-15° downward flare can improve spillover rejection compared with a flat extension, while being much easier to construct than a true parabolic continuation.
For 1420 MHz work on a 1.5 m dish, that often gives more benefit than the extra collecting area itself.
(ChatGPT): I had a look and there appears to be a snag with using Screwfix for this.
Screwfix
- They stock plenty of 32 mm MDPE fittings, but their current MDPE pipe range appears to be only 20 mm and 25 mm coils; I could not find a 32 mm pipe coil listed.
CEF
- CEF mainly stocks electrical conduit rather than MDPE water pipe. Their 32 mm heavy-gauge conduit is about £16.85 per 3 m length.
- Their flexible 32 mm conduit is around £159 for a 50 m coil.
For your dish extension, I would actually consider electrical conduit rather than MDPE water pipe:
- 25 mm heavy-duty PVC conduit is stiffer.
- Available in straight lengths.
- Joins easily with couplers.
- Easier to tension mesh against.
- Less “springy” than MDPE.
However, to form a 2.3-2.5 m diameter ring, 32 mm MDPE remains the easiest single-piece solution.
The best prices I found for 32 mm MDPE coils were:
| Supplier | Product | Price |
|---|---|---|
| JT Dove | 32 mm x 25 m | £38.59 ex VAT |
| BES | 32 mm x 25 m | £47.52 inc VAT |
| Pipetek | 32 mm x 25 m | £58.80 inc VAT |
| Toolstation | about £49.71 |
For a 50 cm extension on a 1.5 m dish, my own choice would be:
- Six aluminium radial straps (which you already have).
- One ring of 32 mm MDPE.
- Stainless self-tappers through the straps into the pipe.
- Aluminium insect mesh or aviary mesh tensioned between the dish rim and outer ring.
That should give a surprisingly rigid “ground shield” extension while remaining lightweight enough not to distort the dish.