DIY Antenna Reflectors and Horns

While not re: the L-band(I loved the DIY back in L-band days) I though this would be a thread for DIY horns, dishes, etc would be useful for those who are at the fringes or outside the published coverage areas. Maybe there is a better place for Ku band antennas and DIY.

I have arranged for an old offset Ku dish or two be available when I am down by the dead sea to try out the signal there. But I have been thinking about writing up designs for everything from space blanket umbrellas to a 1m dish made out of plastic plumbing pipe and window screen. People making the horns could post here too.

As many radio amateurs and DIY hackers here I expect the DIY enthusiasm crosses over. I am of the build the radio and especially the antenna from junk school of thought. Technology is at it’s most fun when you can make it yourself with only a few precision components purchased or recycled. I would love to help push the effort to bring back DIY and get people worldwide to overcome state censorship or poverty and lack of access to Othernet delivery alternate options.

Have you read this on the WiKi regarding Cones and Horns? Ken

Using a Conical shell to improve reception
Several users living on the fringe of SES-2’s ERIP area have discovered using a cone or horn around the Maverick LNB improves SNR by as much as 6 dB in some cases being the only way to close the link. The cones and horns being used are 8 inches tall with an upper diameter of 4 inches (either in diameter, or 4 inches by 4 inches square), and a lower diameter of 2 inches (either in diameter, or 2 inches by 2 inches square). Both martini shakers, solid aluminum or garden mesh wires are being effectively used. Pringles tubes (which are aluminum lined) offer free potato chips while you site your LNB. This has not been confirmed in Europe yet, but should also improve reception.

Yes, but I think making it easy to find in the forums is useful too, without promising anything I have a bit of ambition to write an antenna guide if I can gather enough DIY/hack content, this thread is a convenient place to lay out my scraps where others can see and search in the future even if I slack off.
It really needs a guide of it’s own with good blueprint type diagrams as I feel most antenna designs for commercial, military, and amateur radio need to be simplified while still retaining the required formulae to DIY especially off-band as well as a few no-math implementations.
I am actually surprised that I have not found more than a few K-band DIY designs as a LNB, solar cell, small flat screen, and receiver are pretty small and light but a stamped steel offset dish is big and wonky.

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I had good results using a large stainless steel bowl as a reflector. It was a little difficult to focus because of the flat bottom but I went from -12 snr to -2 snr. I might set this back up tomorrow and take some pictures.

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These bowl, wok, horn and other designs are great!
I want to try to collect as many cardboard/chloroplast & foil designs as possible along with improvised dishes like you are using, I am especially thinking of chloroplast to make the old 90degree horns you saw on the old microwave relay towers might be easier than a dish. Anyone who can do a technical cartoonish drawing like you see in wikihow would make such a guide much better. We need both exact measurements for most end users as well as plug-in formula to go off freq or improvise for stealth etc. as required by this similar projects in the future.
Also needed is creative and weather resistant stands and tripods for horns, dishes, and bare LNBs.
For the stands I think wood is the easiest material most people will have access to.

Good ideas, I always wanted to try and get something that is either common products, or that is flat for shipping… then easily assembled… and durable. My tin foil applied to a plastic cup lasted about one month until a rain storm blow it across the yard.

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That is the big downside to most of the ultralight foil and plastic DIY stuff, it is terrible in weather, the obvious reason why we see galvanized steel dishes.
Two designs I want to try are to get a 1m or larger beach ball and find a good high Al paint(or even a few hundred aluminum shiny dot stickers) for the reflector and elastic rigging inside to hold the LNB at focal point then glue patch shut the holes, I think there is also patent issues if sent out for mass production.
The other is to make a lightweight nomad dish from two identical stamped commercial steel dishes, lay down foil in the bottom dish, resin and a mat or two of fiberglass more foil then weigh down a second dish; trim and paint so we don’t get LNB sunburn.
The ball dish is very portable and the DIY dish factory one is pretty portable too, and can use regular pattern dish mounting hardware and LNB boom.
Both only partly solve portability for non LNB only Othernet areas but not being able to DIY from junk or local non specialized components with only basic tools; on the other hand the foil stuff is wrecked in days outside in most non-perfect weather…

Try the chicken wire mesh. It works as well as foil, but is wind and water resistant. Ken

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Horn?

Either the horn or the cone - -

The horn is 4 (top) x 2 (bottom) x 8 inches, and the cone is 4 inch diameter at the top and 2 inches at the bottom by 8 inches. Ken

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So on Ku band with wavelength at 2.5–1.67 cm the microwaves coming in at that angle the hole size is not a problem, probably get some loss though using same stuff for a dish or reflector.

Can you do a line art drawing with all dimensions before and after assembly?

Here’s the trapezoid pattern I used with both aluminum flashing or 1/4 inch chicken wire:

image

It is very hard to connect the chicken wire together as trapezoid panels, so I made a cone out of it which was easier to connect together as it only required one edge to be connected. Ken

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Here’s another idea I have implemented on my portable terminal - - a stainless steel collapsible drinking cup cut to securely snug over the LNB cover - -


It gives me about a 3 dB improvement in SNR (no effect on Rssi). The bottom is 2 3/8 " diameter, the top is 2 7/8" diameter, and the height is 3". Smaller than the cones and wave guides, but equally effective - - thou a lesser SNR improvement. Ken

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How did you make the case, looks to be a very naval grade rig.

Turns out the case was one of Othernet’s original cases shipped to early supporters who bought into the Crowd Funding a couple of years ago. What Syed did was offer the then “Lantern” device to those who wanted it, or told them to wait for the production model which they are still working on :roll_eyes:

Back then, the “Lantern” was thought to be a L-Band device with a patch antenna run by solar cells. Well that didn’t happen - - but I kept the case and modified it to hold the Dreamctcher board and the LNB which I fixed into the case thru a rubber gasket so I could change the skew. After I concluded a cone improved SNR on the Ku-band LNB (some of us used martini shakers), I though to get a collapsible drinking cup so the cone wouldn’t be so hard to pack. It worked out well. My little traveling Gnome has had a hard life falling of balconies in Europe and getting soaked in the rain.

The case fits nicely into my luggage when I travel, and the electronics don’t move around getting disconnected. Ken

It is very cool, I am trying to come up with an idealized portable othernet rig for some remote work I will be involved with in not too long a time; but like too many DIYish gadgets in my life it will probably end up a bare circuit board wrapped in chloroplast and kapton or something.

FWIW, I collected the results from the various designs I could find in the forums and it is here: https://drive.google.com/file/d/1sd3QmyjGJtz8tH7qSFf-ep6T0RIfjtKh/view

The file is also linked in the Wiki in the horn section.

Will

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I think this is my favorite post.

This is great!! Extra good for having dB improvement numbers; ideally we would have the dB numbers of a pool of users for each and average the improvement score for a given horn or dish design. Exactly this is the kind of stuff that needs to be in the back of the user manual.