Does A Radome Affect Radio?

Not too far away from where this is being written is one of Uncle Sam’s NATO outposts, a satellite earth station for their comms system. Its most prominent feature is a radome, a huge golf-ball-like structure visible for miles, that protects a large parabolic antenna from the British weather. It makes sense not just for a superpower to protect its antennas from the elements, and [saveitforparts] is doing the same with a geodesic dome for his radio telescope experiments. But what effect does it have on the received signal? He’s made a video to investigate.

The US military radome is likely constructed of special RF-transparent materials, but this smaller version has a fibreglass skin and an aluminium frame. When he compares internal and external sky scans made with a small motorised satellite TV antenna he finds that the TV satellites are just as strong, but that the noise floor is higher and the frame is visible in the scan. It’s particularly obvious with such small dish, and his planned larger array should improve matters.

We would be curious to know whether an offset-fed dish constructed to minimise ground noise reaching the LNB, would improve matters further. It’s no surprise that the frame doesn’t impede the TV satellites though, as it is many wavelengths wide at that frequency. The video is below the break, and meanwhile, we featured the antenna he’s using here in 2023.

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Interactive LED Dome Glows With The Best Of Them

With the price and availability of components these days, it’s easier than ever to throw a whole pile of LEDs at a build and get them flashing away. The hard part is doing it well. [Amy Goodchild] is an artist, and has a knack for producing rather beautiful LED projects. The When in Dome installation is no exception.

The build is based around a large geodesic dome, fitted with LED panels that glow and react to the occupants inside. Using the Microsoft Kinect as a sensor enables the dome to map out what’s happening in 3D space, and use this data to guide its animations. WS2812B LED strips were used, in combination with a Fadecandy controller along with Processing. This is a powerful combination which makes designing attractive LED effects easier, without forcing users to go to the effort of writing their own libraries or optimizing their microcontroller code.

For those more interested in the dome itself, you’ll be happy to know that [Amy] doesn’t skimp on the details there either. The build actually started as a commercially available kit, though there’s still plenty of manual cutting, screwing, and painting required. She does an excellent job documenting the dome build through a series of videos, and walks the reader through some of the design decisions she made (and would remake, if given the chance).

People love geodesic domes at the best of times; adding an interactive LED installation just takes things to the next level. We’ve seen them used as greenhouses too, and they make a great hackerspace project as well. Video after the break.

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Building A Geodesic Dome Greenhouse

Greenhouses are a great way to improve conditions for your plants, and are an absolute necessity for any serious gardening in colder climates. When the time came for [gentleworks] to build a new greenhouse, rather than going with a conventional design, they decided to go with a geodesic dome instead.

The greenhouse uses a few techniques that will be unfamiliar to those used to run-of-the-mill carpentry. The individual cedar struts meet at a series of hubs, constructed out of short lengths of Schedule 80 PVC pipe. The struts are attached to the pipe with steel straps, screwed into place. This doesn’t give the strongest of holds, but as most of the loads on the struts are compressive in nature, it works well in practice. Plastic sheeting is used as a covering to help let in plenty of light while keeping the cold out. The greenhouse is also heated, and can maintain a 40 deg F temperature differential with 14,000 BTUs.

It’s a build that has us wanting to throw up a dome or two in our own backyard. We’ve seen other geodesic structures before; if you’re working on one yourself, be sure to drop us a line.