3D Printed Helical Satcom Feed

With the advent of cheap software defined radios made popular by the RTL-SDR project a few years back, satellite communications are now within the budget of even the most modest hacker. For $20 USD you can get a USB SDR module that is more than capable of receiving signals from any number of geosynchronous satellites, but you’ll need something a little more robust than rabbit ears to pick up a signal broadcast from over 22,000 miles away.

Building a satellite-capable antenna isn’t necessarily difficult, but does involve a fair bit of arcane black magic and mathematics to do properly; something that can scare away those new to the hobby. But by using a 3D printed mandrel, [Tysonpower] has come up with a feed you can build and mount on a standard dish without having to take a crash course in antenna theory. [Tysonpower] reports the feed has a center frequency 1550 MHz, and works well for reception of Inmarsat, AERO and HRPT signals.

The channel in the 3D printed core of the feed ensures that the inserted wire is of the correct length and in the perfect position for optimal reception. All you need to do is print the core, wrap it with wire, and then solder the end to a connector on a ground-plane that’s nothing more than a sheet of aluminum. [Tysonpower] was even kind enough to model up a mount that will allow you to bolt this feed to a standard satellite dish.

We’ve previously covered using RTL-SDR to receive Inmarsat transmissions, and hardware for the Outernet project, both of which would be great applications for an antenna like this.

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See Satellites with a Simple Radio Telescope

Have you got a spare Dish Network antenna lying about? They’re not too hard to come by, either curbside on bulk waste day or perhaps even on Freecycle. If you can lay hands on one, you might want to try this fun radio telescope build.

Now, don’t expect much from [Justin]’s minimalist build. After all, you’ll be starting with a rather small dish and an LNB for the Ku band, so you won’t be doing serious radio astronomy. In fact, the BOM doesn’t include a fancy receiver  – just a hacked satellite finder. The idea is to just get a reading of the relative “brightness” of a radio source without trying to demodulate the signal. To that end, the signal driving the piezo buzzer in the sat finder is fed into an Arduino through a preamp. The Arduino also controls stepper motors for the dish’s azimuth and elevation control, which lets it sweep the sky and build up a map of signal intensity. The result is a clear band of bright spots representing the geosynchronous satellites visible from [Justin]’s location in Brazil.

Modifications are definitely on the docket for [Justin], including better equipment that will allow him to image the galactic center. There may be some pointers for him in our coverage of a tiny SDR-based radio telescope, or from this custom receiver that can listen to Jupiter.

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