thin air… based on my prior quick test with cardboard and shrinking a 2x4x8" long to a 2x4x4" long and getting decent results. Looking mainly to shore-up the mechanics of something that seemed to electrically / RF work ok.
After lining the horn cleanly with Aluminum duct tape, I seem to be able to reliably get 3-4dB improvement. The +5 stated earlier must’ve been a fluke or over-zealousness in observations or less-than-optimal baseline measurement on the bare LNB.
I’ve done some EMI/RFI testing before, and note that the GHz frequency antennas tend to have a flared/parabolic horn. With 3D printing a lot more is possible than linear shapes. If there is a good online resource anyone knows about (eg online calculator) I could try some other shapes or angles, etc.
With the same 4" opening, an 8" length gives +20dBi, and a 4" length gives +16dBi. I would call that the same ballpark. Losing 4dB to make it half as big seems like a fair trade
My latest try is using four printed circuit boards… cut in trapezoids … I can ‘unfold’ them to make shipping easier. The phenolic base material may get embrittled by UV exposure… probably will spray with rust-o-leum ( even have some ‘galvanic’ touch up spray )
I am attaching them to the lnb with just a gob / bead of RTV silicon
Is it double-sided copper-clad board? I guess that would help… only the edges would then be exposed.
I entertained the idea of a two-part horn assembly. A 3D printed clamp similar to what I printed the other day, that has a small angled flange to which an otherwise constructed horn screws into. eg use a flat-pack horn like the copper-clad you describe, which folds-out into shape and then screws into the flange on the clamp which then affixes and aligns the whole thing to the LNB.
I wonder about the feasibility of having the main LNB casting directly include a conical horn… at OEM volumes of course.
The cones and wave guides I have made were from aluminum flashing material picked up at a local hardware store. East to cut trapezoids and tape them together with aluminum duct tape. Ken
I just started testing with a 35cm. I’m getting -12 SNR through three walls. Less than 1% packet loss.
This is a similar trade as the cone. Larger device, it can now stay inside. And it was pretty easy to point, though the five degree beam width might be a nuisance for noobs.
That looks great for locations that ‘see’ the satellite through a side exterior wall. Some locations may have the satellite at the zenith… meaning the signal would have to penetrate the roof or possibly a ‘second floor’ and a roof.
Correct, at my house it’s on the first floor and the angle take the line of sight through vertical wall, a second floor, and then a roof. That’s what I meant by three walls.
I think 25cm would be ideal for us, but that is not a commercial size that I’m aware of. These guys do make one 30cm, but it has an integrated LNB and costs a lot.
My local ‘interior decorator’ has rejected the idea of an indoor dish.
Unless it is not visible … like in a closet on a shelf
In this case … size matters.
A dish on the floor in the living room is not going to be an approved installation.
Accommodating your “local interior decorator” is a problem we have all had, but from a different angle - - hiding your antenna so the police won’t find you in Middle East/Russian/Chinese venues is a large concern to many of us not living in North America we need to consider.
I can hardly wait until Othernet is broadcasting to those areas. Innovative stealth ku band antennas are something we all need to think about.
If we can please our “significant others” it might keep our future users alive. Ken
This is fantastic! Would you please share the STL files?
I had a thought about the metalic covering and I reckon some of that spray on copper shielding stuff might work well on top of either PETG or some ABS? Alternatively one could use that Aluminium tape for the heating ducts? Finally, there is such a thing as conductive filament. A chat with Mat at Printed Solid should yield a sample. Be warned however, it is very brittle (been there, done that).
I tried the aluminum tape for heating ducts. After a few days, it started to peel up. The PLA plastic I used to print the horn doesn’t provide the best grip for that type of tape it seems. If you try a liquid/spray coating, please let us know your results.
On the horn, the mounting flanges are sized for #6 hardware btw.
